A Novel Photosynthesis of Carboxymethyl Starch-Stabilized Silver Nanoparticles

Research ArticleA Novel Photosynthesis of Carboxymethyl Starch-StabilizedSilver Nanoparticles

M A El-Sheikh

National Research Centre Textile Research Division El-Behouth Street Dokki PO Box 12311 Giza Egypt

Correspondence should be addressed to M A El-Sheikh drmanalelsheikhgmailcom

Received 13 August 2013 Accepted 4 November 2013 Published 29 January 2014

Academic Editors A Jacquot Y-L Kuo Z Peng R-C Sun A Tonkikh and Z Zhou

Copyright copy 2014 M A El-Sheikh This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

The water soluble photoinitiator (PI) 4-(trimethyl ammonium methyl) benzophenone chloride is used for the first time in thesynthesis of silver nanoparticles (AgNPs) A new green synthesis method involves using PIUV system carboxymethyl starch(CMS) silver nitrate andwater Amechanism of the reduction of silver ions to AgNPs by PIUV system as well as by the newly bornaldehydic groups was proposed The synthesis process was assessed by UV-vis spectra and TEM of AgNPs colloidal solution Thehighest absorbance was obtained using CMS PI and AgNO

3concentrations of 10 gL 1 gL and 1 gL respectively 40∘C 60min

pH 7 and a material liquor ratio 1 20 AgNPs so-obtained were stable in aqueous solution over a period of three weeks at roomtemperature (sim25∘C) and have round shape morphology The sizes of synthesized AgNPs were in the range of 1ndash21 nm and thehighest counts of these particles were for particles of 6ndash10 and 1ndash3 nm respectively

1 Introduction

Silver nanoparticles have unique optical electrical and bio-logical properties that have attracted significant attention dueto their potential use in many applications such as catalysisbiosensing drug delivery and medical textiles [1ndash5]

Techniques used in the formation of nanosizedmetal par-ticles are Top-down and Bottom-up techniques Top-down ismechanically based on diminishing processes that start frombulk metals Bottom-up technique predominantly employsthe chemical or electrochemical reduction of metal salts insolutionThermolytic photolytic radiolytic laser irradiationmicrowave heating or sonochemical procedures as wellas the decomposition of appropriate metastable precursormolecules complete thewide spectrumof synthetic pathwaystometal nanoparticlesThe formation of nanoparticles occurswhen individual neutral atoms are subjected to collide withother atoms resulting in a nucleation to smaller or largerparticles [6]

Sodium borohydride hydroxylamine hydrochloridedimethylamine borane sodium citrate hydrazine monohy-drate sodium formate trimethylamine borane sodiumtrimethoxyborohydride and formaldehyde have all becomeroutine reducing agents for the generation of metal NPs

Among the various reducing agents BH4minus plays the domi-nant role These chemicals are highly reactive and causepotential environmental and biological risks [7 8]Utilizationof nontoxic chemicals environmentally gentle solvents andrenewable materials is one of the key issues that worthimportant consideration in a green synthesis policy

Direct photoreduction and photosensitization are power-ful approaches for the in situ synthesis in polymer matrixes[9ndash16] The heart of the photochemical approach is thegeneration of M0 (metal nanoparticles) in such conditionsthat their precipitation is thwarted Metal nanoparticles canbe formed through direct photoreduction of a silver sourcesilver salt or complex or reduction of silver ions using pho-tochemically generated intermediates such as radicals Thephotoreduction is often promoted by dyes dispersed or dis-solved in the polymer or present in the chemical structure ofthematrixThe visible light photoinitiator ldquocamphorquinonerdquowas used to generate electron-donating radicals upon pho-tolysis Subsequent oxidation of these radicals to the cor-responding cations in the presence of silver hexafluoroan-timonate (AgSbF

6) leads to the simultaneous formation of

silver nanoparticlesThe key step of the process is the reactionof silver cations with photogenerated transient species thatare able to reduce them to silver metal atoms Two classes of

Hindawi Publishing Corporatione Scientific World JournalVolume 2014 Article ID 514563 11 pageshttpdxdoiorg1011552014514563

2 The Scientific World Journal

photoinduced reactions were used to produce these primaryradicals The first one is based on the reaction of an electronrich molecule (eg amine thiol and ether) with the highlyoxidant triplet state of a sensitizer excited upon absorptionof the actinic photons The second one involves the directhemolytic photocleavage of a sigma bond (mainly CndashC bondsadjacent to a carbonyl) [17]

Since the polymers prevent agglomeration and precipi-tation of the particles they have been frequently employedas capping or stabilizing agents in the chemical synthesisof metal nanoparticles Among methods of green synthesisof silver nanoparticles water is used as an environmentallybenign solvent and polysaccharides as a capping agent or insome cases polysaccharides serve as both a reducing and acapping agent [4 8 18ndash27] In a case of dual polysaccharidefunction silver nanoparticles were synthesized by the reduc-tion of Ag+ inside of nanoscopic starch templates The exten-sive network of hydrogen bonds in the templates providessurface passivation or protection against nanoparticle aggre-gation [26] Biosynthesis is also an alternative green tech-nique for synthesis of silver nanoparticles [2 28ndash31]

The so-called ldquoalcohol reduction processrdquo is a very generalprocess for the production of metal nanoparticles oftenstabilized by organic polymers In general the alcohols whichwere useful reducing agents contained 120572-hydrogen and wereoxidized to the corresponding carbonyl compounds Theoxidation of primary alcohols (RndashCH

2OH) byAg+ is alsowell

established the reaction is slow and requires heating to beaccelerated as follows

2Ag+ + RndashCH2OH 997888rarr 2Ag0 + 2H+ + RndashCHO (1)

However such a reaction is a very slow process and con-stitutes a minor route for Ag+ reduction in comparison withthe photoinduced generation of AgNPs described hereafter[11 32]

Bottom et al [33 34] developed and assessed the effi-ciency of a novel water-soluble photosensitizer 4-(trimethylammonium methyl) benzophenone chloride and used it forthe photoinitiated graft copolymerization of 2-hydroxyethylacrylate onto cellulose El-Sheikh and coworkers [35ndash38]further utilized this efficient photoinitiator in the graft copol-ymerization of acrylic acid and acrylamide onto car-boxymethyl starch and in the photooxidation of starch Theabove cited references are the only ones found in the liter-ature about the using of 4-(trimethyla mmonium methyl)benzophenone chloride To the best of the authorrsquos knowledgeand according to literature survey the later has never beenused in the photosynthesis of AgNPs

Benzophenone compounds are powdersThey can absorband dissipate UV radiation Benzophenone compounds areused in bath products makeup products hair productssunscreens and skin care products They protect the skinfrom the harmful effects of the sun

According to the literature survey one can describe theprocess as a ldquonovelrdquo process According to the use of the ben-zophenone compounds in cosmetics one can describe thephotoinitiator used in this research work as a safe eco-friendly and green compound

In this work a novel green method was adopted to syn-thesize AgNPs using the water soluble 4-(trimethyl ammo-nium methyl) benzophenone chlorideUV system and silvernitrate as a precursor in the presence of a water soluble poly-mer (CMS)While PI photogenerate AgNPs CMS act as botha reducing and stabilizing agent All components are watersoluble the process is ldquosimple and easyrdquo and the synthesisconditions used are mild Parameters affecting the synthesisof AgNPs such as PI silver nitrate and CMS concentra-tions as well as reaction time and temperature are studiedThe synthesized AgNPs were assessed by measuring theabsorbance of the colloidal solution the size the shape andthe stability of the synthesized AgNPs

2 Experimental

21 Materials Native maize starch (St) was kindly suppliedby the Egyptian Company for Starch and Glucose Manufac-ture Cairo Egypt

4-(Trimethyl ammonium methyl) benzophenone chlo-ride a water soluble photoinitiator that belongs to the benzo-phenone series (UV Absorbers) was supplied by ldquoThe asso-ciated Octel Ltd Widnes UKrdquo and used without furtherpurification

Monochloroacetic acid sodium hydroxide sodium car-bonate silver nitrate hydrochloric acid acetic acid ethanoland isopropanol were laboratory grade chemicals

22 Equipment The irradiation reaction vessel consists of aquick fit water-cooled 125W medium-pressure Hg lampassembly as a UV irradiation source immersed in a quick fit150mL cylindrical tube The total dose of the UV irradiationwas controlled by controlling the time of exposure that is thereaction timeThe reaction temperature was controlled usinga thermostatic water bath

23 Method231 Carboxymethylation Water soluble carboxymethylstarch with DS = 02 was prepared according to a reportedmethod [39] In this method 100 g ofmaize starch was placedin a sealable bottle and mixed together with a known volumeof isopropanol An aqueous solution of sodium hydroxide(05molemole St) was added dropwise to the starchmdashisopropanol mixture under stirring until the whole amountof sodium hydroxide was added The sodium salt solutionof monochloroacetic acid (02molemole St) prepared bythe reaction of monochloroacetic acid with the equivalentamount of sodium carbonate was added dropwise to thestarchmdashisopropanolmdashsodiumhydroxidemixture under con-tinuous stirring until the complete addition of the sodiummonochloroacetate solution Stirring was then stoppedand the bottle was closed and kept at 30∘C for 24 hoursAfter carboxymethylation the CMS samples were washedwith ethanol water solution (80 20) while excess alkaliwas neutralized using acetic acid After washing the CMSsamples were filtered and oven-dried at 70∘C

The Scientific World Journal 3

232 Preparation of Silver Nanoparticles In a beaker aknown weight of CMS was mixed with certain volume ofdistilled water using a mechanical stirrer After completedissolution of CMS an aqueous solution of PI was added tothe CMS solution followed by adding silver nitrate solutionunder continuous stirring until completemixing of the wholecontents Doing so the beaker contents were poured in theirradiation tube and transferred to a thermostatic water bathwith a magnetic stirrer The UV lamp is now immersed inthe solution to just above the bottom of the tube to allow themagnet tomove and to allow thewhole solution to be exposedto the UV irradiation The temperature was then allowedto rise gradually until the required temperature is reachedFinally the UV lamp is switched on and the whole contentswere kept at the synthesis temperature for a known period oftime under continuous stirring After synthesis the yellowishbrown colloidal solution is kept in a sealable bottle at roomtemperature (25∘C)

24 Characterizations and Analyses The DS of the carbox-ymethylated starch samples was determined via the determi-nation of the carboxyl content according to a reportedmethod [40]

The UV-vis spectra of silver nanoparticles and PI wererecorded using UV-2401 UV-vis Spectrophotometer Shi-madzu Japan at wavelength range from 190 to 550 nm120582maxat 256 nm is characteristic of PI whereas 120582max at 390ndash420is characteristic of silver nanoparticles Synthesis of silvernanoparticles is expressed as the absorbance of the colloidalsolution of the samples under testThe absorbance the broad-ening and the wavelength of the band measure the intensityof the colloidal solution that is the conversion of silverions to AgNPs Very concentrated AgNPs samples did notshow one smooth band (either sharp or broad) but showeda number of crowded sharp bands This behavior leads tofalse readings So concentrated samples which showed thisbehavior were diluted ldquo119909rdquo times and the obtained absorbancevalue was then multiplied by ldquo119909rdquo to obtain the actualabsorbance value The accuracy of this dilution techniquewas tested by comparing the absorbance readings of certainsamples with moderate concentration before and after dilu-tion The readings were found approximately the same aftermultiplying by ldquo119909rdquo times of dilutions

Transmission Electron Microscope was used to charac-terize AgNPs Thus the shape and size of the synthesizedsilver nanoparticles were characterized by means of a JEOL-JEM-1200 Transmission Electron Microscope The sampleswere prepared by placing a drop of the colloidal solutionon a 400-mesh copper grid coated by an amorphous carbonfilm and evaporating the solvent in air at room temperatureThe average diameter of the silver nanoparticles was deter-mined from the diameter of nanoparticles found in severalchosen areas in enlarged microphotographs The particlesize was measured from the TEM image using the softwareldquoRevolution v160b195rdquo a simple electron microscope toolfor acquiring images maps and spectra using the SpectralEngine 1999ndash2002 4pi analysis Inc

Stability of the silver nanoparticles was tested by storingsamples in sealed glass bottles in a dark place at room

temperature (sim25∘C) and then recording the spectra of thecolloidal solutions after oneweek twoweeks and threeweeksof storing using UV-vis Spectrophotometer

3 Results and Discussions

31 Mechanism of Photosynthesis of AgNPs 4-(Trimethylammonium methyl) benzophenone chloride structure isrepresented in Scheme 1(a) Under UV light excitation 4-(trimethyl ammonium methyl) benzophenone chloride (inan aqueous medium) is first promoted to its excited singletstate (1) then via fast intersystem crossing (ISC) it convertsinto triplet state (2) In the presence of CMS which acts asa H-donor the triplet transient state can undergo hydrogenabstraction with CMS to yield reactive radical species (3)Inactive species formation could take place by the combina-tion of two radicals of PI (4) forming the pinnacol derivative(I) (Scheme 1(b)) The greater the extent of formation ofcompound I is the more pronounced the inactivation of thephotosynthesis process is [35ndash37] The formation of CMS∙radical (3) initiates a photooxidation reaction which leads tothe generation of new aldehydic end groups in theCMSchainThe hydroxyl and carboxyl groups originally present in theCMS molecules in addition to the newly generated aldehydicend groups due to the photooxidation reaction all can act asreducing groups of the Ag+ to Ag0 ((6) and (7)) In additionthe radical of the PI formed according to (3) can furtherreduce the silver ions to AgNPs as shown in (5) Accordinglyone can expect a very efficient reducing system that arosefrom (a) reducing groups of CMS molecules (b) radicalsof CMS and (c) radicals of PI At the same time while thereduction is keeping on and AgNPs grow gradually CMS willfurther form a stable protection layer on the AgNPs surface

Factors affecting the reduction and stability as well asthe shape and size of the formed AgNPs along with reactionmechanism are given below

32 Effect of Photoinitiator Concentration on the Formationof Silver Nanoparticles Different concentrations of PI (from05 to 2 gL) were used to study the effect of increasingthe concentration of PI on the extent of photosynthesis ofAgNPs Thus photosynthesis was carried out using PIUVsystem for one hour of UV irradiation at 30∘C using CMSand AgNO

3concentrations of 50 gL and 1 gL respectively

and a material liquor ratio (M L ratio) 1 20 at pH 7 Thedependence of the absorbance of the colloidal solution of thesynthesized AgNPs on the concentration of PI is shown inFigure 1 Figure 1 shows that regardless of the concentrationof PI four intensive bands with symmetrical bell shapesand high absorbance values at 390ndash420 nm are formed Thisindicates the formation of AgNPs [26 41] and reflects theefficiency of the current system in synthesizing AgNPs atthe synthesis conditions The results obtained from Figure 1shows also that increasing the concentration of PI from 05 to1 gL is accompanied by a dramatic increase in the absorbanceof the colloidal solution Maximum absorbencies (at 120582 =410 nm) of the colloidal solutions ofAgNPs synthesized using05 gL and 1 gL were 409 and 558 respectively Incorpo-ration of PI into the PIUV system enhances the formation


I

C

O

2Ag+ + R998400-CH2OH + 2H+ + R998400-CHO2Ag0

OHHO C C

R R

C

O

R

lowast3

(in aqueous solution) 2 radicals

HO

C R CMS∙+

HO

C R + Ag+ R + H++ Ag0

ISC

h

h

C

O

R

lowast3

C

O

R

lowast1

(in aqueous solution)

C

O

R

1

hC

O

R

lowast1


(1)

(2)

(3)

(4)

(5)

(6)

(7)

CMS

∙

∙

C

O

Where R =

C

O

ROr

CH2ndashNndash(CH3)3Clminus+


(a)

(b)

2Ag0 + 2H+ + R998400-COOH2Ag+ + R998400-CHO + H2O

Scheme 1 (a) Chemical structure of PI (b) Mechanism of photosynthesis of AgNPs


0

20

40

60

80

100

120

140

160

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

05 gL1gL

15 gL2gL

Figure 1 Effect of photoinitiator concentration on the synthesis ofsilver nanoparticles [CMS] 50 gL [PI] 05ndash2 gL [AgNO

3] 1 gL

temp 30∘C time 60min M L ratio 1 20 pH 7

of CMS∙ radical (3) Consequently initiates a photooxidationreaction resulting in the generation of new aldehydic endgroups in the CMS chain In their turn the newly bornaldehydic groups reduce theAg+ to Ag0 At the same time theformation of PI∙ radical (3) and the interaction of this radicalwith AgNO

3(5) can further reduce silver ions to AgNPs Fur-

ther increase in PI concentration from 1 to 2 gL was accom-panied by marginal decrease in the absorbance (nearly level-ing off state is achieved) This could be due to the formationof the pinnacol derivative (I) (4) which in its turn leads tothe inactivation of the photosynthesis of AgNPs

The four sharp bands at 256 nm are representing the PIAs is clear (Figure 1) the intensity of the bands increases withincreasing the concentration of PI from 05 to 2 gL reflectinga steady state of concentration of PI The consumption of thePI in formation of PI∙ radical (3) or the pinnacol derivative(I) (4) is amended by the reformation of PI (5) according toits ldquolife circlerdquo shown in (1)ndash(5)

33 Effect of Silver Nitrate Concentration on the Synthesis ofSilver Nanoparticles To study the effect of increasing theconcentrations of AgNO

3on the photosynthesis of AgNPs

different concentrations of AgNO3(from 05 to 2 gL) were

used Thus photosynthesis was carried out using PIUVsystem for one hour of UV irradiation at 30∘Cusing CMS andPI concentrations of 50 gL and 1 gL respectively and aM Lratio 1 20 at pH 7 The dependence of the absorbance of thecolloidal solution of the synthesizedAgNPs on the concentra-tion of AgNO

3is shown in Figure 2 It shows three intensive

bell shaped bands at AgNO3concentration of 05 gL 1 gL

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

05 gL1gL

15 gL2gL

Figure 2 Effect of silver nitrate concentration on the synthesis ofsilver nanoparticles [CMS] 50 gL [PI] 1 gL [AgNO

3] 05ndash2 gL


and 15 gLThe fourth band representing AgNO3concentra-

tion of 2 gL band is broad without the bell shape characteris-ticsThe figure also shows that the absorbance of the colloidalsolution increases by increasing the concentration of AgNO

3

from 05 to 1 gL after which it decreases It seems from theabove findings that incorporation of PI into the PIUV systemin a concentration of 1 gL enhances the formation of CMS∙radical and PI∙ (3) in an amount just enough for the conver-sion of the Ag+ to Ag0 when the concentration of AgNO

3

is in the range of 05ndash1 gL More reducing groups and moreradicals are required to guarantee the conversion of all Ag+ toAg0 when AgNO

3concentration is to be increased to more

than 1 gL This could be achieved by increasing both PI andAgNO

3concentration together in a parallel way It is also

likely that higher concentration of AgNO3acts in favor of

agglomeration of the silver particles rather than in the for-mation of capped silver nanoparticles in a colloidal solution[5]

34 Effect of Carboxymethyl Starch Concentration on theSynthesis of Silver Nanoparticles Figure 3 shows the UV-vis absorption spectra of the colloidal solution of AgNPsprepared using different concentrations of CMS (10ndash40 gL)The data reveal that regardless of the CMS concentrationused four similar bands are formed at the four concentrationsof CMS with a symmetrical bell shape which is characteristicof the formation of AgNPs It is clear also that there is agradual decrease in the absorption intensity by increasingthe CMS concentration from 10 to 40 gL It should bementioned that the least amount of CMS in the reaction


0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

10 gL20 gL

30gL40gL

Figure 3 Effect of carboxymethyl starch concentration on thesynthesis of silver nanoparticles [CMS] 10ndash40 gL [PI] 1 gL[AgNO

3] 1 gL temp 30∘C time 60min M L ratio 1 20 pH 7

medium (10 gL) together with 1 gL of PI is enough for fullreduction of the Ag+ to Ag0 and efficient for stabilization ofthe formed AgNPsThe decrease in the absorbance as a resultof increasing the concentration of CMS could be ascribed tothe very concentrated mixture which decreases the mobilityof PI and AgNO

3and hinders the conversion of Ag+ to Ag0

35 Effect of Irradiation Time on the Synthesis of SilverNanoparticles The irradiation dose was controlled by con-trolling the irradiation time this is also the time of the photo-synthesis reaction A study of the irradiation time took placeusing irradiation duration from 30 to 120min The depen-dence of the absorbance of the colloidal solution of the syn-thesized AgNPs on the irradiation time is shown in Figure 4Results in Figure 4 reveal that regardless of irradiation timefour similar bands are formed at the four irradiation dura-tions with a symmetrical bell shape which is characteristicof the formation of AgNPs It can also be seen from thefigure that increasing the irradiation time from 30 to 60minis accompanied by an increase in the absorbance It is alsoclear that absorbance values at 60ndash120min are nearly thesame showing a state of leveling off The favorable effect ofincreasing the irradiation time on the synthesis of AgNPs isdue to the formation of PI∙ radicals which in turn producethe CMS∙ radicals by H-abstraction from CMS The roleof these radicals in the conversion of Ag+ to Ag0 is clearlydescribed in Section 32 Leveling off at 60ndash120min meansthat nomore conversion to silver nanoparticles will take placeat the set of reaction conditions It should be mentioned that

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

30 min60 min

90 min120 min

Figure 4 Effect of irradiation time on the synthesis of silvernanoparticles [CMS] 10 gL [PI] 1 gL [AgNO

3] 1 gL temp 30∘C

time 30ndash120min M L ratio 1 20 pH 7

30∘C

40∘C

50∘C

60∘C

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

Temperature (∘C)

Figure 5 Effect of reaction temperature on the synthesis of silvernanoparticles [CMS] 10 gL [PI] 1 gL [AgNO

3] 1 gL temp 30ndash

60∘C time 60min M L ratio 1 20 pH 7


0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

After synthesisAfter one week

After two weeksAfter three weeks

(a)

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)



(b)

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)



(c)

Figure 6 Stability of silver nanoparticles synthesized at different conditions after one week two weeks and three weeks of storing (a) [CMS]50 gL [PI] 1 gL [AgNO

3] 1 gL temp 30∘C time 60min M L ratio 1 20 pH 7 (b) [CMS] 50 gL [PI] 1 gL [AgNO

3] 15 gL temp

30∘C time 60min M L ratio 1 20 pH 7 (c) [CMS] 10 gL [PI] 1 gL [AgNO3] 1 gL temp 30∘C time 60min M L ratio 1 20 pH 7


0

10

20

30

40

50

60

70

Cou

nt (

)

Particle size (nm)1ndash5

M 100 kx

6ndash10 11ndash15 16ndash20

(a)

M 300kx0

10

20

30

40

50

60

70

Cou

nt (

)

Particle size (nm)1ndash3 4ndash6 7ndash8

(b)

0

10

20

30

40

50

60

Cou

nt (

)

Particle size (nm)

M 200 kx


(c)

Figure 7 TEM micrograph and particle size distribution histogram of silver nanoparticles synthesized at different synthesis conditions (a)[CMS] 50 gL [PI] 1 gL [AgNO


3] 15 gL

temp 30∘C time 60min M L ratio 1 20 pH 7 (c) [CMS] 10 gL [PI] 1 gL [AgNO3] 1 gL temp 30∘C time 60min M L ratio 1 20

pH 7


60min of irradiation is enough for full reduction of the Ag+to Ag0 nanoparticles

36 Effect of Reaction Temperature on the Synthesis of SilverNanoparticles To study the effect of increasing the synthesistemperature on the photosynthesis of AgNPs different tem-peratures (from 30 to 60∘C) were applied The dependenceof the absorbance of the colloidal solution of the synthesizedAgNPs on the synthesis temperature is shown in Figure 5Results in Figure 5 show that regardless of photosynthesistemperature similar bands are formed at all the photosynthe-sis temperatures under study with a symmetrical bell shapewhich is characteristic of the formation of AgNPsThe resultsobtained from Figure 5 also show that increasing the photo-synthesis temperature from 30∘C to 40∘C is accompanied byan increase in the absorbance followed by a decrease in theabsorbance by raising the temperature to 50ndash60∘C Increasingthe temperature favors the formation of PI∙ radicals whichin turn produce the CMS∙ radicals by H-abstraction fromCMS The role of these radicals in the conversion of Ag+to Ag0 is clearly described in Section 32 Further increasein the reaction temperature (50ndash60∘C) favors the formationof the pinnacol derivative (I) according to (4) Consequentlythe inactivation of the photosynthesis process is more pro-nounced

37 Stability of Silver Nanoparticles Synthesized at DifferentConditions after One Week Two Weeks and Three Weeksof Storing Stability of photosynthesized AgNPs was testedby measuring the absorbance of the colloidal solution aftersynthesis after one week after two weeks and after threeweeks of storing Figure 6 shows absorbance of the colloidalsolution of samples synthesized at different conditions

Figure 6 reveals that regardless of storing duration andthe set of the synthesis conditions similar bands are formedfor all samples with a symmetrical bell shape which is charac-teristic of the AgNPs Figure 6(a) shows that the absorbancecurves and the absorbance maxima after one two and threeweeks of storing are identical with an even higher absorbancevalue than that after synthesisThese data reveal that up to oneweek of storing the reaction was continued at room temper-ature until all silver ions are converted to AgNPs followed bystability of the colloidal solution after such a long period ofstoring Figure 6(b) confirms the findings of Figure 6(a) thatthe lowest absorbance is related to the AgNPs of the freshlyprepared sample and that storing even enhances the completeconversion of silver ions to AgNPs In Figure 6(c) the case isdifferent and the highest absorbance was related to the freshlyprepared sample Marginal decrease was noticed in theabsorbance of samples stored for one two and three weeksrespectively The decrease in the absorbance is very littleand does not seem to affect the stability of the synthesizedAgNPsThe only affecting parameter among samples a b andc is the concentration of CMS CMS concentration in samplesa and b is 50 gL while it is 10 gL for sample c This mayexplain the continuity of the synthesis reaction for samplesldquoardquo and ldquobrdquo but not for sample ldquocrdquo where the initiation stepsuccessfully generated the CMS∙ radical which in its turninitiates an oxidation reaction resulting in the generation of

new aldehydic end groups capable of reducing Ag+ to Ag0Although such a reaction is very slow and constitutes aminorroute for Ag+ reduction at such a set of reaction conditions(room temperature and pH 7) the long storing time canfinally lead to the formation of AgNPs

38 TEMMicrograph and Particle Size DistributionHistogramof Silver Nanoparticles Synthesized at Different Synthesis Con-ditions The same AgNPs samples used for the stability testwere again used to establish theTEMmicrograph andparticlesize distribution histogram Figure 7 shows that regardlessof the reaction conditions the three micrographs show thatsilver nanoparticles have round shape morphology and finedispersion Some aggregates were noticed in the micrographof sample a The mean particle sizes are between 1ndash20 nm 1ndash8 nm and 1ndash21 nm for samples a b and c respectively Someirregularly shaped particles were found in Figure 7(a) whichcould be due to aggregations of some nanoparticles Thehighest count was found for AgNPs between 6ndash10 1ndash3 and1ndash5 for samples a b and c respectively

4 Conclusions

4-(Trimethyl ammonium methyl) benzophenone chloride (awater soluble photoinitiator) PIUV system carboxymethylstarch (a water soluble ecofriendly polymer) and water (asolvent) were used to synthesis AgNPs using silver nitrate asa precursor Thus the chemicals and the process are greenThe reduction of Ag+ to Ag0 was successfully achieved viathe generation of active PI∙ and CMS∙ free radicals Optimalreaction conditions that yield the highest absorbance valueswere CMS PI and AgNO

3concentrations of 10 gL 1 gL

and 1 gL respectively at 40∘C for 60min at pH 7 using aM L ratio of 1 20 AgNPs so-obtainedwere stable in aqueoussolution over a period of three weeks at room temperature(sim25∘C) and they have a round shape morphology The sizesof synthesized AgNPs were found in the range of 1ndash21 nm andthe highest counts of these particles were for particles of 6ndash10 and 1ndash3 nm respectively

Conflict of Interests

The author declares that there is no conflict of interestsregarding the publication of this paper

References

[1] M H El-Rafie A A Mohamed T I Shaheen and A HebeishldquoAntimicrobial effect of silver nanoparticles produced by fungalprocess on cotton fabricsrdquo Carbohydrate Polymers vol 80 no3 pp 779ndash782 2010


[3] A Hebeish F A Abdel-Mohdy M M G Fouda et al ldquoGreensynthesis of easy care and antimicrobial cotton fabricsrdquo Carbo-hydrate Polymers vol 86 no 4 pp 1684ndash1691 2011


[4] A Hebeish M E El-Naggar M M G Fouda M A RamadanS S Al-Deyab and M H El-Rafie ldquoHighly effective antibacte-rial textiles containing green synthesized silver nanoparticlesrdquoCarbohydrate Polymers vol 86 no 2 pp 936ndash940 2011

[5] A Hebeish A El-Shafei S Sharaf and S Zaghloul ldquoNovel pre-cursors for green synthesis and application of silver nanopar-ticles in the realm of cotton finishingrdquo Carbohydrate Polymersvol 84 no 1 pp 605ndash613 2011

[6] G Schmid ldquoSyntheses and Characterizations 33 Synthesisof Metal Nanoparticlesrdquo in Nanoparticles From Theory ToApplication G Schmid Ed pp 214ndash239 Wiley-VCH VerlagGmbH amp Co KGaA Weinheim Germany 2010

[7] P Dallas V K Sharma and R Zboril ldquoSilver polymeric nano-composites as advanced antimicrobial agents classificationsynthetic paths applications and perspectivesrdquo Advances inColloid and Interface Science vol 166 no 1-2 pp 119ndash135 2011

[8] N Vigneshwaran R P Nachane R H Balasubramanya and PV Varadarajan ldquoA novel one-pot rsquogreenrsquo synthesis of stable silvernanoparticles using soluble starchrdquo Carbohydrate Research vol341 no 12 pp 2012ndash2018 2006

[9] L Balan and D Burget ldquoSynthesis of metalpolymer nanocom-posite by UV-radiation curingrdquo European Polymer Journal vol42 no 12 pp 3180ndash3189 2006

[10] L Balan M Jin J-P Malval H Chaumeil A Defoin and LVidal ldquoFabrication of silver nanoparticle-embedded polymerpromoted by combined photochemical properties of a 27-diaminofluorene derivative dyerdquoMacromolecules vol 41 no 23pp 9359ndash9365 2008

[11] L Balan J-PMalval R SchneiderD LeNouen andD-J Loug-not ldquoIn-situ fabrication of polyacrylate-silver nanocompositethrough photoinduced tandem reactions involving eosin dyerdquoPolymer vol 51 no 6 pp 1363ndash1369 2010

[12] L Balan R Schneider and D J Lougnot ldquoA new and con-venient route to polyacrylatesilver nanocomposites by light-induced cross-linking polymerizationrdquo Progress in OrganicCoatings vol 62 no 3 pp 351ndash357 2008

[13] C Decker L Keller K Zahouily and S Benfarhi ldquoSynthesisof nanocomposite polymers by UV-radiation curingrdquo Polymervol 46 no 17 pp 6640ndash6648 2005

[14] L Keller C Decker K Zahouily S Benfarhi J M Le Meinsand J Miehe-Brendle ldquoSynthesis of polymer nanocompositesbyUV-curing of organoclay-acrylic resinsrdquo Polymer vol 45 no22 pp 7437ndash7447 2004

[15] Y Yagci O Sahin T Ozturk S Marchi S Grassini andM Sangermano ldquoSynthesis of silverepoxy nanocomposites byvisible light sensitization using highly conjugated thiophenederivativesrdquo Reactive and Functional Polymers vol 71 no 8 pp857ndash862 2011

[16] Y Yagci M Sangermano and G Rizza ldquoA visible light photo-chemical route to silver-epoxy nanocomposites by simultane-ous polymerization-reduction approachrdquo Polymer vol 49 no24 pp 5195ndash5198 2008

[17] L Balan J PMalval andD J Lougnot ldquoIn situ photochemicallyassisted synthesis of silver nanoparticles in polymer matrixesrdquoin Silver Nanoparticles D P Perez Ed pp 79ndash92 In-TechCroatia 2010

[18] J Chen J Wang X Zhang and Y Jin ldquoMicrowave-assistedgreen synthesis of silver nanoparticles by carboxymethyl cellu-lose sodium and silver nitraterdquoMaterials Chemistry and Physicsvol 108 no 2-3 pp 421ndash424 2008

[19] V Djokovic R Krsmanovic D K Bozanic et al ldquoAdsorptionof sulfur onto a surface of silver nanoparticles stabilized with

sago starch biopolymerrdquo Colloids and Surfaces B vol 73 no 1pp 30ndash35 2009

[20] M H El-Rafie M E El-Naggar M A Ramadan M M GFouda S S Al-Deyab and A Hebeish ldquoEnvironmental syn-thesis of silver nanoparticles using hydroxypropyl starch andtheir characterizationrdquo Carbohydrate Polymers vol 86 no 2pp 630ndash635 2011

[21] A A Hebeish M H El-Rafie F A Abdel-Mohdy E S Abdel-Halim and H E Emam ldquoCarboxymethyl cellulose for greensynthesis and stabilization of silver nanoparticlesrdquo Carbohy-drate Polymers vol 82 no 3 pp 933ndash941 2010

[22] HHuangQ Yuan andX Yang ldquoPreparation and characteriza-tion of metal-chitosan nanocompositesrdquo Colloids and SurfacesB vol 39 no 1-2 pp 31ndash37 2004

[23] M Z Kassaee A Akhavan N Sheikh and R Beteshobabrudldquo120574-Ray synthesis of starch-stabilized silver nanoparticles withantibacterial activitiesrdquoRadiation Physics andChemistry vol 77no 9 pp 1074ndash1078 2008

[24] W Liu Z Zhang H Liu W He X Ge and M Wang ldquoSilvernanorods using HEC as a template by 120574-irradiation techniqueand absorption dose that changed their nanosize and morphol-ogyrdquoMaterials Letters vol 61 no 8-9 pp 1801ndash1804 2007

[25] P Raveendran J Fu and S L Wallen ldquoA simple and ldquogreenrdquomethod for the synthesis of Au Ag and Au-Ag alloy nanopar-ticlesrdquo Green Chemistry vol 8 no 1 pp 34ndash38 2006

[26] V K Sharma R A Yngard and Y Lin ldquoSilver nanoparticlesgreen synthesis and their antimicrobial activitiesrdquo Advances inColloid and Interface Science vol 145 no 1-2 pp 83ndash96 2009

[27] M Valodkar A Bhadoria J Pohnerkar M Mohan and SThakore ldquoMorphology and antibacterial activity of carbohy-drate-stabilized silver nanoparticlesrdquo Carbohydrate Researchvol 345 no 12 pp 1767ndash1773 2010

[28] S Kaviya J Santhanalakshmi and B Viswanathan ldquoBiosynthe-sis of silver nano-flakes by Crossandra infundibuliformis leafextractrdquoMaterials Letters vol 67 no 1 pp 64ndash66 2012

[29] Z Sadowski ldquoBiosynthesis and application of silver and goldnanoparticlesrdquo in Silver Nanoparticles D P Perez Ed pp 257ndash276 In Tech 2010

[30] A Saxena R M Tripathi F Zafar and P Singh ldquoGreensynthesis of silver nanoparticles using aqueous solution of Ficusbenghalensis leaf extract and characterization of their antibac-terial activityrdquoMaterials Letters vol 67 no 1 pp 91ndash94 2012

[31] P Vankar and D Shukla ldquoBiosynthesis of silver nanoparticlesusing lemon leaves extract and its application for antimicrobialfinish on fabricrdquo Applied Nanoscience vol 2 no 2 pp 163ndash1682012

[32] J S Bradley G Schmid D V Talapin E V Shevchenko and HWeller ldquoSyntheses and characterizations 32 synthesis of metalnanoparticlesrdquo inNanoparticles FromTheory ToApplication pp185ndash238 Wiley-VCH Verlag GmbH amp Co KGaA 2005

[33] R A Bottom J T Guthrie and P N Green ldquoThe influence ofH-donors on the photodecomposition of selected water-solublephotoinitiatorsrdquoPolymer Photochemistry vol 6 no 1 pp 59ndash701985

[34] R A Bottom J T Guthrie and P N Green ldquoThe photo-chemically induced grafting of 2-hydroxyethyl acrylate ontoregenerated cellulose films from aqueous solutionsrdquo PolymerPhotochemistry vol 6 no 2 pp 111ndash123 1985

[35] M A El-Sheikh Synthesis of New Polymeric Materials Basedon Water-Soluble Starch Composites [PhD thesis] Faculty ofScience Cairo University Egypt 1999


[36] M A El-Sheikh ldquoPhoto grafting of acrylamide onto carboxy-methyl starch I Utilization of the product in easy care finishingof cotton fabricrdquo in Proceedings of the 3rd Aachen-DresdenInternational Textile Conference pp 1ndash30 Aachen 2009

[37] M A El-Sheikh M A Ramadan and A El-Shafie ldquoPhotooxidation of rice starch II Using a water soluble photo initiatorrdquoCarbohydrate Polymers vol 78 no 2 pp 235ndash239 2009

[38] M A ElSheikh and J T Guthrie ldquoGraft copolymerization ofacrylic acid onto carboxymethyl starch using UV-irradiationrdquoin Proceedings of the 213th National Meeting A C Society Edvol 213 ACS San Francisco Calif USA 1997

[39] M A El-Sheikh ldquoCarboxymethylation of maize starch at mildconditionsrdquo Carbohydrate Polymers vol 79 no 4 pp 875ndash8812010

[40] G C Daul R M Reinhardt and J D Reid ldquoPreparation ofsoluble yarns by the carboxymethylation of cottonrdquo TextileResearch Journal vol 23 no 10 pp 719ndash726 1953

[41] E S Abdel-Halim M H El-Rafie and S S Al-Deyab ldquoPoly-acrylamideguar gum graft copolymer for preparation of silvernanoparticlesrdquo Carbohydrate Polymers vol 85 no 3 pp 692ndash697 2011

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

The Scientific World Journal

Impact Factor 173028 Days Fast Track Peer ReviewAll Subject Areas of ScienceSubmit at httpwwwtswjcom


photoinduced reactions were used to produce these primaryradicals The first one is based on the reaction of an electronrich molecule (eg amine thiol and ether) with the highlyoxidant triplet state of a sensitizer excited upon absorptionof the actinic photons The second one involves the directhemolytic photocleavage of a sigma bond (mainly CndashC bondsadjacent to a carbonyl) [17]

Since the polymers prevent agglomeration and precipi-tation of the particles they have been frequently employedas capping or stabilizing agents in the chemical synthesisof metal nanoparticles Among methods of green synthesisof silver nanoparticles water is used as an environmentallybenign solvent and polysaccharides as a capping agent or insome cases polysaccharides serve as both a reducing and acapping agent [4 8 18ndash27] In a case of dual polysaccharidefunction silver nanoparticles were synthesized by the reduc-tion of Ag+ inside of nanoscopic starch templates The exten-sive network of hydrogen bonds in the templates providessurface passivation or protection against nanoparticle aggre-gation [26] Biosynthesis is also an alternative green tech-nique for synthesis of silver nanoparticles [2 28ndash31]

The so-called ldquoalcohol reduction processrdquo is a very generalprocess for the production of metal nanoparticles oftenstabilized by organic polymers In general the alcohols whichwere useful reducing agents contained 120572-hydrogen and wereoxidized to the corresponding carbonyl compounds Theoxidation of primary alcohols (RndashCH

2OH) byAg+ is alsowell

established the reaction is slow and requires heating to beaccelerated as follows

2Ag+ + RndashCH2OH 997888rarr 2Ag0 + 2H+ + RndashCHO (1)

However such a reaction is a very slow process and con-stitutes a minor route for Ag+ reduction in comparison withthe photoinduced generation of AgNPs described hereafter[11 32]

Bottom et al [33 34] developed and assessed the effi-ciency of a novel water-soluble photosensitizer 4-(trimethylammonium methyl) benzophenone chloride and used it forthe photoinitiated graft copolymerization of 2-hydroxyethylacrylate onto cellulose El-Sheikh and coworkers [35ndash38]further utilized this efficient photoinitiator in the graft copol-ymerization of acrylic acid and acrylamide onto car-boxymethyl starch and in the photooxidation of starch Theabove cited references are the only ones found in the liter-ature about the using of 4-(trimethyla mmonium methyl)benzophenone chloride To the best of the authorrsquos knowledgeand according to literature survey the later has never beenused in the photosynthesis of AgNPs

Benzophenone compounds are powdersThey can absorband dissipate UV radiation Benzophenone compounds areused in bath products makeup products hair productssunscreens and skin care products They protect the skinfrom the harmful effects of the sun

According to the literature survey one can describe theprocess as a ldquonovelrdquo process According to the use of the ben-zophenone compounds in cosmetics one can describe thephotoinitiator used in this research work as a safe eco-friendly and green compound

In this work a novel green method was adopted to syn-thesize AgNPs using the water soluble 4-(trimethyl ammo-nium methyl) benzophenone chlorideUV system and silvernitrate as a precursor in the presence of a water soluble poly-mer (CMS)While PI photogenerate AgNPs CMS act as botha reducing and stabilizing agent All components are watersoluble the process is ldquosimple and easyrdquo and the synthesisconditions used are mild Parameters affecting the synthesisof AgNPs such as PI silver nitrate and CMS concentra-tions as well as reaction time and temperature are studiedThe synthesized AgNPs were assessed by measuring theabsorbance of the colloidal solution the size the shape andthe stability of the synthesized AgNPs

2 Experimental

21 Materials Native maize starch (St) was kindly suppliedby the Egyptian Company for Starch and Glucose Manufac-ture Cairo Egypt

4-(Trimethyl ammonium methyl) benzophenone chlo-ride a water soluble photoinitiator that belongs to the benzo-phenone series (UV Absorbers) was supplied by ldquoThe asso-ciated Octel Ltd Widnes UKrdquo and used without furtherpurification

Monochloroacetic acid sodium hydroxide sodium car-bonate silver nitrate hydrochloric acid acetic acid ethanoland isopropanol were laboratory grade chemicals

22 Equipment The irradiation reaction vessel consists of aquick fit water-cooled 125W medium-pressure Hg lampassembly as a UV irradiation source immersed in a quick fit150mL cylindrical tube The total dose of the UV irradiationwas controlled by controlling the time of exposure that is thereaction timeThe reaction temperature was controlled usinga thermostatic water bath

23 Method231 Carboxymethylation Water soluble carboxymethylstarch with DS = 02 was prepared according to a reportedmethod [39] In this method 100 g ofmaize starch was placedin a sealable bottle and mixed together with a known volumeof isopropanol An aqueous solution of sodium hydroxide(05molemole St) was added dropwise to the starchmdashisopropanol mixture under stirring until the whole amountof sodium hydroxide was added The sodium salt solutionof monochloroacetic acid (02molemole St) prepared bythe reaction of monochloroacetic acid with the equivalentamount of sodium carbonate was added dropwise to thestarchmdashisopropanolmdashsodiumhydroxidemixture under con-tinuous stirring until the complete addition of the sodiummonochloroacetate solution Stirring was then stoppedand the bottle was closed and kept at 30∘C for 24 hoursAfter carboxymethylation the CMS samples were washedwith ethanol water solution (80 20) while excess alkaliwas neutralized using acetic acid After washing the CMSsamples were filtered and oven-dried at 70∘C















I

C

O

2Ag+ + R998400-CH2OH + 2H+ + R998400-CHO2Ag0

OHHO C C

R R

C

O

R

lowast3


HO

C R CMS∙+

HO

C R + Ag+ R + H++ Ag0

ISC

h

h

C

O

R

lowast3

C

O

R

lowast1


C

O

R

1

hC

O

R

lowast1


(1)

(2)

(3)

(4)

(5)

(6)

(7)

CMS

∙

∙

C

O

Where R =

C

O

ROr



(a)

(b)




0

20

40

60

80

100

120

140

160

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

05 gL1gL

15 gL2gL


3] 1 gL












0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

05 gL1gL

15 gL2gL


3] 05ndash2 gL




3


3









0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

10 gL20 gL

30gL40gL






0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

30 min60 min

90 min120 min


3] 1 gL temp 30∘C


30∘C

40∘C

50∘C

60∘C

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

Temperature (∘C)





0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)



(a)

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)



(b)

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)



(c)



3] 15 gL temp



0

10

20

30

40

50

60

70

Cou

nt (

)


M 100 kx


(a)

M 300kx0

10

20

30

40

50

60

70

Cou

nt (

)


(b)

0

10

20

30

40

50

60

Cou

nt (

)

Particle size (nm)

M 200 kx


(c)



3] 15 gL


pH 7








4 Conclusions






References






























































I

C

O

2Ag+ + R998400-CH2OH + 2H+ + R998400-CHO2Ag0

OHHO C C

R R

C

O

R

lowast3


HO

C R CMS∙+

HO

C R + Ag+ R + H++ Ag0

ISC

h

h

C

O

R

lowast3

C

O

R

lowast1


C

O

R

1

hC

O

R

lowast1


(1)

(2)

(3)

(4)

(5)

(6)

(7)

CMS

∙

∙

C

O

Where R =

C

O

ROr



(a)

(b)




0

20

40

60

80

100

120

140

160

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

05 gL1gL

15 gL2gL


3] 1 gL












0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

05 gL1gL

15 gL2gL


3] 05ndash2 gL




3


3









0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

10 gL20 gL

30gL40gL






0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

30 min60 min

90 min120 min


3] 1 gL temp 30∘C


30∘C

40∘C

50∘C

60∘C

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

Temperature (∘C)





0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)



(a)

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)



(b)

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)



(c)



3] 15 gL temp



0

10

20

30

40

50

60

70

Cou

nt (

)


M 100 kx


(a)

M 300kx0

10

20

30

40

50

60

70

Cou

nt (

)


(b)

0

10

20

30

40

50

60

Cou

nt (

)

Particle size (nm)

M 200 kx


(c)



3] 15 gL


pH 7








4 Conclusions






References

















































0

20

40

60

80

100

120

140

160

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

05 gL1gL

15 gL2gL


3] 1 gL












0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

05 gL1gL

15 gL2gL


3] 05ndash2 gL




3


3









0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

10 gL20 gL

30gL40gL






0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

30 min60 min

90 min120 min


3] 1 gL temp 30∘C


30∘C

40∘C

50∘C

60∘C

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

Temperature (∘C)





0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)



(a)

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)



(b)

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)



(c)



3] 15 gL temp



0

10

20

30

40

50

60

70

Cou

nt (

)


M 100 kx


(a)

M 300kx0

10

20

30

40

50

60

70

Cou

nt (

)


(b)

0

10

20

30

40

50

60

Cou

nt (

)

Particle size (nm)

M 200 kx


(c)



3] 15 gL


pH 7








4 Conclusions






References

















































0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

10 gL20 gL

30gL40gL






0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

30 min60 min

90 min120 min


3] 1 gL temp 30∘C


30∘C

40∘C

50∘C

60∘C

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)

Temperature (∘C)





0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)



(a)

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)



(b)

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)



(c)



3] 15 gL temp



0

10

20

30

40

50

60

70

Cou

nt (

)


M 100 kx


(a)

M 300kx0

10

20

30

40

50

60

70

Cou

nt (

)


(b)

0

10

20

30

40

50

60

Cou

nt (

)

Particle size (nm)

M 200 kx


(c)



3] 15 gL


pH 7








4 Conclusions






References

















































0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)



(a)

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)



(b)

0

20

40

60

80

100

120

140

190 220 250 280 310 340 370 400 430 460 490 520 550

Abso

rban

ce

Wavelength (nm)



(c)



3] 15 gL temp



0

10

20

30

40

50

60

70

Cou

nt (

)


M 100 kx


(a)

M 300kx0

10

20

30

40

50

60

70

Cou

nt (

)


(b)

0

10

20

30

40

50

60

Cou

nt (

)

Particle size (nm)

M 200 kx


(c)



3] 15 gL


pH 7








4 Conclusions






References

















































0

10

20

30

40

50

60

70

Cou

nt (

)


M 100 kx


(a)

M 300kx0

10

20

30

40

50

60

70

Cou

nt (

)


(b)

0

10

20

30

40

50

60

Cou

nt (

)

Particle size (nm)

M 200 kx


(c)



3] 15 gL


pH 7








4 Conclusions






References























































4 Conclusions






References
















































A Novel Photosynthesis of Carboxymethyl Starch-Stabilized Silver Nanoparticles

Documents

Transcript of A Novel Photosynthesis of Carboxymethyl Starch-Stabilized Silver Nanoparticles