SYNTHESIS AND CHARACTERIZATIONS OF COPPER NANOPARTICLES MATERIAL

MINISTRY OF EDUCATION AND TRAINING VIETNAM ACADEMY SCIENCE AND TECHNOLOGY GRADUATE UNIVERSITY OF SCIENCE AND TECHNOLOGY CAO VAN DU SYNTHESIS AND CHARACTERIZATIONS OF COPPER NANOPARTICLES MATERIAL Specialization: inorganic chemistry Code number: 62 44 01 13 DOCTORAL THESIS ABSTRACTS’ INORGANIC CHEMISTRY Ho Chi Minh City – 2016 The work was completed at: Laboratory nano Lac Hong University, Laboratory of nano University of Natural Sciences, Institute for Materials Science Applications, Vietnam Academy of Science and Technology Scientific guidance: Assoc Prof Dr Nguyen Thi Phuong Phong Dr Nguyen Thi Kim Phuong 1st Peer Reviewer: 2nd Peer Reviewer: 3rd Peer Reviewer: The theeesis dissertation will be defended in front of doctoral thesis judgement, held at the Academy of Sciences Institute of Applied Materials, Graduate University of Science and Technology , No , Mac Dinh Chi , District 1, HCMC city, Viet Nam At , ……………, 2016 Can learn dissertation at the library: National Library of Vietnam, Library of Vietnam Academy of Science and Technology INTRODUCTION In recent years, metal nanoparticles have attracted the attention of scientists due to their special properties that differ distinctly from the corresponding bulk materials by surface area to volume ratio and small size of them The ability to synthesize metal nanoparticles with different shapes and sizes is important to explore their applications in electronics, catalysis, sensors, optical and biological devices As most of these applications were governed by silver, gold and platinum However, the high cost constraint of these metals restricted their applications in high volume production Presently, copper nanoparticles provided a good alternative of silver, gold and platinum nanoparticles because of their lower cost and catalytic activity, novel electronic, optical and magnetic properties or have antibacterial and antifungal properties Compared to other metal nanoparticles materials, the synthesis of copper nanoparticles are more difficult because of surface easy oxidizing of copper Therefore, the synthesis of copper nanoparticles with high purity would be a prerequisite for many application areas such as electricity electronics, optics, catalysis, chemistry, biology Up to now, several methods have been developed for the preparation of copper nanoparticles, such as electron irradiation, the plasma process, chemical reduction method, in situ methods, two-step reduction method, thermal decomposition, electro-chemical reduction, reduction with ultrasound, microwave heating, supercritical methods, Methods for the preparation of copper nanoparticles often common aim is to create nanoparticles at small sizes, high-stability for maximize applications However, a large number of published on synthetic of copper nanoparticles still has many disadvantages, such as long time or high temperatures to complete the reaction, copper salts were chemically reduced in organic solvents under strict conditions, complex equipment systems, using capping agents not guarantee for the stability of the copper nanoparticles colloidal solutions Moreover, in the most recent published works, one of the most important applications of the copper nanoparticles was tested for antibacterial to treat and kill drug-resistant microorganisms The results showed that copper nanoparticles colloidal solutions shown bactericidal activity with various gram (-), gram (+) cause disease in humans and animals Antifungal activity has not been mentioned much, only published work of Sahar M Ouda (2014) showed results in resistance against two strains of plant pathogenic fungi on Botrytis cinerea is Alternaria alternate and Botrytis cinerea On this basis, to overcome the disadvantages of synthetic copper nanoparticles with traditional chemical reaction system The content of the thesis is performed primarily with the synthesis of copper nanoparticles from the basic reaction systems including precursor, protection and reducing agent The limitations of these reaction system will be improved by the synthesis of the new systems that is a combination of two or three protections The combination of protective substances include protection of large molecular weight (PVA) and the protection of small molecular weight (trisodium citrate, ascorbic acid, CTAB) will make new rules of the synergistic effect in order to control the size and ensure the stability of copper nanoparticles The thesis also clarified the physicochemical and biological characteristics of copper nanoparticles materials forming The main contents of the thesis: - Synthesis of the copper nanoparticles colloidal solutions by chemical reduction method with various precursors including copper oxalate, CuCl2, CuSO4, Cu(NO3)2 with hydrazine hydrate reducing agent, NaBH4; solvent glycerin and water, PVA and PVP protection, dispersants and protective agents: including trisodium citrate, ascorbic acid, CTAB - Investigating the influence of the parameters in the synthesis to the shape, size and distribution of copper nanoparticles forming such as reaction temperature, concentration of reducing agent, the ratio of precursors and capping agent, solution pH - Investigating the effect of the protective agent PVA, PVP, dispersants trisodium citrate, ascorbic acid protect auxiliaries, CTAB surfactant to the size and distribution of copper nanoparticles forming - Investigating the specific physicochemical properties of copper nanoparticles forming by the modern analytical methods such as UV-Vis spectrum, X-ray diffraction (XRD), transmission electron microscopy (TEM) - Investigating the antifungal activity and high killing ability against Corticium salmonicolor of the copper nanoparticles colloidal solutions in the laboratory Meaning of science and practice of the thesis The thesis provides the basis for the study a systematic process of synthetic copper nanoparticles material overview domestic and foreign researches The results of the thesis will make clarify the rules of relationship between the size of copper nanoparticles forming with their special characteristic is surface plasmon resonance via UV-Vis spectrum By using a various of precursors, reducing agents, protective agents, the synthesis was performed with the survey parameters which control the size of copper nanoparticles forming, from that explore best bioavailability of the copper nanoparticles colloidal solutions This is also the scientific basis for subsequent applied research The layout of the thesis: The thesis has 128 pages with tables, 108 figures Besides the introduction (3 pages), conclusions (2 pages), list of publications (2 pages) and references is updated to 2015 (9 pages), Annex (11 pages) The thesis is divided into chapters as follows: Chapter : Overview 28 pages Chapter : Experimental 10 pages Chapter : Results and discussions 74 Pages New contributions of the thesis The first time thesis presented a systematic synthesis of the copper nanoparticles colloidal solutions base on chemical process with various precursors including copper oxalate, CuCl2, CuSO4, Cu(NO3)2, various reducing agents: hydrazine hydrate, NaBH4; protective agents: PVA and PVP, dispersant and protective agents: trisodium citrate, ascorbic acid, CTAB in solvent: glycerin and water The novelty of the thesis was use glycerin solvent and protective agents (PVP, PVA, trisodium citrate) to ensure the formation of colloidal solutions with high stability Rules, relationships between the size of copper nanoparticles with absorption peak shift through surface plasmon resonance from UV-Vis analysis were characterised and clarified Characterization: Using the chemical reduction method with reducing agent hydrazine hydrate, NaBH4 to synthesize the copper nanoparticles colloidal solutions from precursors (copper nitrate, copper chloride, copper sulfate) Using thermal reducing method with the used glycerol both solvent and reduction to synthesis the copper nanoparticles colloidal solutions from copper oxalate precursors Using thermal analysis DTA-TG to determine temperature ranges that CuC2O4 changes volume, creating the basis for the synthesis of copper nanoparticles from copper oxalate precursors Using UV-Vis to determine the optical properties, the shift plasmon absorption peaks of copper nanoparticles Predicting the size of copper nanoparticle forming Using X-ray diffraction (XRD) to determine the crystal structure, the purity of the copper nanoparticles Using TEM to determine the morphology, size, combined with IT3 software to perform particle size distribution of copper nanoparticles Using invitro testing method and spray directly method for testing antifungal activity and high killing ability against C salmonicolor RESULTS AND DISCUSSION 3.1 Synthesis of copper nanoparticles from copper oxalate precursors 3.1.2 Investigating the influence of the parameters on the size of copper nanoparticles 3.1.2.1 Effect of temperature Figure 3.5 is the result UV-Vis spectrum of the copper nanoparticles colloidal solutions, the results showed: - Curve (a): UV-Vis spectrum of the mixture CuC2O4 dispersed in glycerin, only show an absorbance peak at 305 nm wavelength; this is the absorbance peak of the copper oxalate - Curve (b): UV-Vis spectrum of the samples was prepared at reaction temperature of 220 oC, reaction time was minutes The results show that besides the absorbance peak at 305 nm wavelength, There is an absorbance peak appears at wavelength 580 nm This is the absorbance peak of copper nanoparticles, this phenomenon was result of the surface plasmon resonance that occurs with copper nanoparticles This result indicates that the reaction had occurred to form copper nanoparticles, but the reaction did not occur completely, therefor still has copper oxalate in solution This result compare with the result of the thermal analysis DTA - TG Figure 3.4 could conclude that the reaction did not occur by the thermal decomposition mechanism, because the reaction of thermal decomposition copper oxalate only occurs at temperatures of 270 °C Thus, with the result obtained, it can be concluded that the reaction formed copper nanopaticles occurs in both thermal reduction and chemical reduction mechanism with glycerin acts as both solvent and reduction - Curve (c): Samples were prepared at temperature of 230 oC, UV-Vis results showed that there was only the absorbance peak at 584 nm wavelength; not appears absorbance peak of copper oxalate Thus, the reduction of copper oxalate has occurred almost completely Figure 3.5: UV-Vis spectra of (a) copper oxalate, (b) CuNPs + copper oxalate (220 °C, (c) and CuNPs (230 oC) Figure 3.6: TEM and particle size distribution of CuPNs were synthesized at 230 oC) Figure 3.6: TEM and particle size distribution of CuPNs were synthesized at 240 oC) Copper nanoparticles were synthesized at 240 °C with unchanged reaction conditions Figure 3.6 and 3.7 are TEM images and particle size distributions of copper nanoparticles were synthesized at temperature of 230 °C and 240 °C At temperatures of 230 °C, the copper nanoparticles were created in spherical, had average diameter in range of 12 ± 3.6 nm (Figure 3.6) At temperature of 240 °C, copper nanoparticles have spherical with the average size in range of 29.6 ± 4.2 nm (Figure 3.7) 3.1.2.2 Effect of ratio CuC2O4/PVP Table 3.1: Data and results of the copper nanoparticles were synthesized via ratio CuC2O4/PVP Samples ratio (%) CuC2O4/PVP PVP (g) K1 0.002 580 5.5 ± 2.3 K2 0.006 585 … K3 0.010 592 36 ± K4 598 … K5 0.018 600 68 ± 6.3 K6 11 0.022 614 … K7 15 0.030 623 … 0.2 CuC2O4 (g) 0.014 Temperature Absorbance Average size via (oC) peak (nm) TEM (nm) 230 Table 3.1 shows summarily UV-Vis and TEM results of the copper nanoparticles colloidal solutions The results showed that all samples had phenomenon of surface plasmon resonance which occurs with copper nanoparticles at the position of maximum absorbance peaks were K1 (580 nm), K2 (585 nm ), K3 (592 nm), K4 (598 nm), K5 (600 nm), K6 (614nm), K7 (623 nm) corresponding to ratio CuC2O4 / PVP is 1, 3, 5, 7, 9, 11 , 15%, respectively The absorbance peaks of the copper nanoparticles colloidal solutions shift to larger wavelengths (redshift) from 580 to 623 nm, while the intensity of the absorance peaks also increased According to Mie theory, it could be predicted that the size of copper nanoparticles increase when the ratio CuC2O4/PVP increases from to 15 % The results of TEM images in Figure 3.11 to Figure 3.13 show that, at concentration % of CuC2O4 compared to PVP, copper nanoparticles were created mostly in spherical and distributed with the average size was 5.5 ± 2.3 nm (Figure 3.11) When concentration of CuC2O4 increase to % (Figure 3.12) and % (Figure 3.13) compared to PVP, copper nanoparticles forming were distributed in a wide range and agglomerated, with the average size 36 ± nm and 68 ± 6.3 nm, respectively These results were consistent entirely compared to the shift position of maximum absorance peaks of copper nanoparticles in the UV-Vis spectrum from 580 to 600 nm Figure 3.11: TEM image and particle size distribution of CuNPs were synthesized in the weight ratio CuC2O4 /PVP = % Figure 3.12: TEM image and particle size distribution of CuNPs were synthesized in the weight ratio CuC2O4 /PVP = % Figure 3.13: TEM image and particle size distribution of CuNPs were synthesized in the weight ratio CuC2O4 /PVP = % 3.1.2.3 Effect of pH Initial solution has neutral pH values, to investigate the influence of solution pH to the formation of copper nanoparticles colloidal solutions, the reaction solution was controlled pH by NaOH 0.1 M All samples were prepared with the same condition such as CuC2O4/PVP = %, the reaction time was minutes Preliminary experiments showed that when the solution pH of the mixture increases, the reaction to form copper nanoparticles occurs at lower temperatures (140 °C) Observe the change of color in the solution pH adjustment process as well as the actual reaction occured, the synthesis mechanism was changed and can be explained as follows: when adding NaOH to the mixture along with mixing, the mixture of copper oxalate in glycerol changed the color from light blue to dark blue, this could be the formation of complex [Cu(OH)4]2+, this complex could be bonded with PVP at the position of nitrogen and oxygen in a chain of molecule PVP Thus, potential redox (ECu2+/Cu) changed and made the ΔG value of reaction was more negative, therefor the temperature of the reaction in the case of high solution pH ( 8) will be lower (140 °C) compared to the reaction occurs at neutral solution pH (230 oC) Table 3.2: Data and results of the copper nanoparticles were synthesized via solution pH Samples pH Ratio (%) Temperature Absorbance Value CuC2O4/PVP (oC ) peak (nm) K3 D1 D2 D3 D4 10 11 D5 12 230 140 Average size via TEM (nm) Particle shape 592 36 ± spherical 596 600 601 601 … 77 ± 5.3 82 ± 4.2 … spherical, polygon spherical, polygon 600 96 ± 5.6 spherical, cubic, triangle, rod The results were summarized in Table 3.2 shows that, when the pH value increases in ÷ 12, the copper nanoparticles had phenomenon of surface plasmon resonance corresponding to maximum absorbance peaks at wavelengths 596; 600; 601; 601; 600 nm, respectively TEM images showed that, when the solution pH increases, the size of copper nanoparticles forming also increases Specific, the average size of the copper nanoparticles at pH = 9, pH = 10, pH = 12 in range of 77 ± 5.3 nm (Figure 3.16), 82 nm ± 4.2 (Figure 3.17), 96 ± 5.6 nm (Figure 3.18), respectively In particular, copper nanoparticles were formed not only spherical but also cubic, triangle, rod, polygon Figure 3.16: TEM image and particle size distribution of CuNPs were synthesized at solution pH = Figure 3.17: TEM image and particle size distribution of CuNPs were synthesized at solution pH = 10 Figure 3.18: TEM image and particle size distribution of CuNPs were synthesized at solution pH = 12 3.2 Synthesis of copper nanoparticles from copper salt precursors 3.2.1 Synthesis of copper nanoparticles from copper nitrate precursors 3.2.1.1 Effect of the concentration of reducing agent Figure 3.22 to Figure 3.24 were TEM images and the particles size distribution of copper nanoparticles were synthesized at different concentrations of reducing agent Figure 3.22 shows that, at HH concentration 0.1 M, the copper nanoparticles forming had smallest average size (14 ± nm) However, the particle size distribution was created in the wide range from ÷ 47 nm, mostly in spherical and combined of smaller particle size When increases HH concentrations from 0.2 to 0.5 M, the copper nanoparticles were created in spherical and monodisperse with average size 25 ± nm (Figure 3.23) and 67 ± nm (Figure 3.24) respectively Figure 3.22: TEM image and particle size distribution of CuNPs were synthesized at HH concentration 0.1 M Figure 3.23: TEM image and particle size distribution of CuNPs were synthesized at HH concentration 0.2 M Figure 3.24: TEM image and particle size distribution of CuNPs were synthesized at HH concentration 0.5 M 3.2.1.2 Effect of temperature Figure 3.27: TEM image and particle size distribution of CuNPs were synthesized at 110 oC Figure 3.28: TEM image and particle size distribution of CuNPs were synthesized at 130 oC Figure 3.29: TEM image and particle size distribution of CuNPs were synthesized at 150 oC Figure 3.27 to 3.29 were TEM images and particle size distribution of the copper nanoparticles were synthesized at different temperatures At temperatures of 110 °C (Figure 3.27), the copper nanoparticles were created in spherical, monodisperse with average size of 17 ± nm As the temperatures were higher, at 130 °C (Figure 3.28) and 150 °C (Figure 3.29) the copper nanoparticles forming had larger size, in a wide range with the average size 33 ± nm and 50 ± 20 nm respectively 3.2.1.3 Effect of ratio Cu(NO3)2/PVP Figure 3.32: TEM image and particle size distribution of CuNPs were synthesized with ratio of Cu(NO3)2/PVP =1% Figure 3.33: TEM image and particle size distribution of CuNPs were synthesized with ratio of Cu(NO3)2/PVP =3% Figure 3.33: TEM image and particle size distribution of CuNPs were synthesized with ratio of Cu(NO3)2/PVP =7% The results of TEM images from Figure 3:32 to 3:34 shows, as ratio of Cu(NO3)2/PVP was %, the copper nanoparticles were formed mainly in spherical, monodisperse in range of ± nm (Figure 3.32) When the ratio of Cu(NO3)2/PVP increased to 3% and 7%, the copper nanoparticles were formed still in spherical and had diameter with average size of 15 ± nm (Figure 3:33) and 22 ± nm (Figure 3:34) respectively, the copper nanoparticles were agglomerated  Summary and general discussion about the results of copper nanoparticles were synthesized from copper oxalate and copper nitrate precursors when using only PVP as protective agent: Table 3.4: Summary the results of copper nanoparticles were synthesized from copper oxalate and copper nitrate precursors Precursors/ synthetic conditions Agents Synthetic conditions Results of UVVis (nm) The best synthesis conditions copper oxalate Copper oxalate Glycerol PVP 1.000.000 g/mol Copper nitrate Glycerol Temp (oC) Concentra tions of reducing agents Ratio Copper oxalate/ PVP Temp (oC) Concentrations of reducing agents HH (M) … ÷ 15% … 580 ÷ 600 210 ÷ 240 580 ÷ 584 Temp 230 oC Results of TEM Copper nitrate Concentra tions of reducing agents … 110 ÷ 160 573 ÷ 602 01 ÷ 0,5 ÷ 9% 580 ÷ 590 568 ÷ 600 Ratio Copper oxalate/ PVP Temp Concentrations of reducing agents 1% 110 0,2 M 5,5 ± 2,3 nm Hydrazine hydrate Ratio Copper nitrate/ PVP Ratio Copper nitrate/ PVP 1% ± nm Table 3.4 are the results of copper nanoparticles which were synthesized by using PVP as a protective agent The results could be more explained as follows: - The size of copper nanoparticles forming are difficult to control through the survey parameters Specifically, position of the plasmon absorbance peaks shifted in large range of wavelengths when the temperature, concentration of reducing agent, ratio of precursor/protective agent were changed These could be predicted that the size of nanoparticle were changed and distributed in the wide range of sizes Through TEM images analysis, the prediction was confirmed and clarified - At the best conditions, copper nanosparticles formming had the smallest average size (2.3 ± 5.5 nm from copper oxalate precursor and ± nm from copper nitrate precursor) However, these results were achieved by using with small amount of precursor (ratio precursor/protectant = %), corresponding to low concentration of copper nanoparticles were obtained in this procedure Thus, it can be concluded that the copper nanoparticles were produced by using PVP (Mw: 1,000,000 g/mol) as a protective agent The steric stabilisation of copper nanoparticles were achieved in this procedure However, because of the large size of polymer molecules so it is difficult to coat all generated mainly in the spherical, with narrow distribution, the average size of copper nanoparticles are ± and ± nm respectively b Effect of ratio Cu(NO3)2/PVP in the presence of trisodium citrate Figure 3.41: UV–Vis spectra of copper nanoparticles were synthesized by using ratio of Cu(NO3)2/PVP from to 15 % Figure 3.42: TEM image and particle size distribution of CuNPs were synthesized by using ratio of Cu(NO3)2/PVP = % Figure 3.43: TEM image and particle size distribution of CuNPs were synthesized by using ratio of Cu(NO3)2/PVP = % The copper nanoparticles colloidal solution were synthesized in the presence of trisodium citrate, the results of the UV-Vis analysis were shown in figure 3.41 The results shown that, the increase in the ratio of Cu(NO3)2/PVP, the intensity of absorbance peak also increased However, the shift of the maximum absorbance peak changed in narrow wavelength Specifically, when the ratio of Cu(NO3)2/PVP increased from to 13 %, the position of the maximum absorbance peak was displayed at the wavelength from 562 to 564 nm As the ratio of Cu(NO3)2/ PVP increased to 14 and 15 %, the position of maximum absorbance peak shifted to longer wavelengths (two the tallest peaks) at 566 and 568 nm respectively These signals indicated that the larger of the particles were prepared by using the ratio of Cu(NO3)2/PVP greater than 13 % Figure 3.42, 3.38 and 3.43 are TEM images of copper nanoparticles colloidal solutions which were prepared by using the ratio of Cu(NO3)2/PVP = %, % and % in the presence of trisodium citrate The results shown that, with the ratio of Cu(NO3)2/PVP = %, the copper nanoparticles were generated mainly in the spherical, with narrow distribution, its diameter appears in a range of the average size of ± nm (Figure 3.42) Copper nanoparticles were created with similar results by using the ratio of Cu(NO3)2/PVP = % and %, its diameter appears in a range of the average size of ± nm (Figure 3.38 ) and ± nm (Figure 3.43) respectively These results fited perfectly with the results of UV-Vis analysis in Figure 3.41 This study will be the basis for the syntheis of copper nanoparticles with narrow distribution, small size and high performance 3.2.2 Synthesis of copper nanoparticles from copper cloride precursors 3.2.2.1 The basis on the synthesis of copper nanoparticles from copper chloride precursors Based on the results from the synthesis of copper nanoparticles from copper nitrate salt, this study will focus on the synthesis of copper nanopaticles colloidal solution from copper chloride sprecursor The process was performed according to the synthesis of copper nitrate precursor, the parameters of the investigating will be prepared with the reaction agents including copper chloride precursor, hydrazine 10 hydrate reducing agent, protective agent PVP (MW = 58,000 g/mol), solvent glycerol, trisodium citrate dispersant agent The best parameters were used to synthesize copper nanoparticles colloidal solution by using PVA (Mw = 60,000 g/mol) as protective agent The results from these investigating will be collated with the result of the synthesis copper nanoparticles from copper nitrate precursors From that, the rules of the synergistic effect of large molecular weights (PVP, PVA) and small molecular weight (trisodium citrate) will be made clearly, the best system protection for the synthesis of copper nanoparticles from this conclution will be clarified 3.2.2.2 investigating of parameters on the size of copper nanoparticles According to the results of Xiao-Feng Tang [13], Mustafa BICER [16], Mohammad Vaseem [18], ZHANG Qiu-li [21] as they synthesized copper nanoparticles by chemical reduction method with the different of reaction agents (table 1.1) or in the study with copper xalate and copper nitrate precursors of the thesis The parameters such as temperature or concentration of the reducing agent has strong influence on the size and distribution of the copper nanoparticles forming However, the relationship between the size, the distribution of particles with the parameters of the synthesis in various reaction systems still need to clarify In this study, the effect of various parameters on the size and distribution of copper nanoparticles will be clarified when the protective polymer (PVP, PVA) and trisodium citrate were used together a Effect of temperature Figure 3.45: UV–Vis spectra of copper nanoparticles were synthesized from copper chloride at diffirent temp from 100 to 160 oC Hình 3.47: UV–Vis spectra of copper nanoparticles were synthesized with various of reducing agent concentration hydrazinezin hydrate from 0,1 to 0,7M Figure 3:45 is UV-Vis spectra of copper nanoparticles colloidal solution which were synthesized at different temperatures The results shown that, when the temperature increased from 100 to 160 °C, the position of the maximum absorbance peak unchanged or changed very little The absorbance peak appeared at the wavelength from 562 to 564 nm These results predicted that the size of copper nanoparticles forming changed a little when temperature were controlled from 100 to 160 °C In addition, in the range of wavelength 400 ÷ 500 nm does not appear strange peaks, which may be concluded that the copper nanoparticles were created by protected surface, not oxidized, the product has high purity and not has Cu2O On other hand, compared to the the results of the investigating according to the temperature from copper nitrate It could be confirmed the role of trisodium citrate as dispersant agent to controll the 11 size of copper nanoparticles forming: when trisodium citrate was used with appropriate content, the copper nanoparticles were synthesized with small size and uniformity in the range of temperature 100 ÷ 160 oC or larger b Effect of the concentration of reducing agent Figure 3.48: TEM image and particle size distribution of CuNPs were synthesized at HH concentration 0.2 M Figure 3.49: TEM image and particle size distribution of CuNPs were synthesized at HH concentration 0.5 M Figure 3.50: TEM image and particle size distribution of CuNPs were synthesized at HH concentration 0.7 M Figure 3.47 is UV-Vis spectra of copper nanoparticles colloidal solution which were synthesized at diffirent concentration of reducing agent The results shown that, the position of the maximum absorbance peak was shifted to longer wavelengths when the concentration of reducing agent increased from 0.1 to 0.7 M Specifically, the position of the absorbance peaks are 562 nm (0.1 M; 0.2 M; 0.3 M); 563 nm (0.4 M); 567 nm (0.5 M); 572 nm (0.6 M); 580 nm (0.7 M) respectively This result could be predicted that the copper nanoparticles with small size and hight stable were prepared by using the concentrations of reductant from 0.1 to 0.4 M When the concentration of reducing agent increased from 0.5 to 0.7 M, the reaction happen faster, the formation of nucleation was greater in the short time There for, the protective agent trisodium citrate and PVP could not cover the surface of copper nanoparticles Thus, the aggregation of nanoparticles occurred to perform larger size Figure 3.48, 3.49, 3.50 are TEM images and size distribution of copper nanoparticles that were synthesized at different concentration of reducing agent The results shown that, at concentration of reducing agent HH 0.2 M, the copper nanoparticles were prepared mostly in spherical, uniform distribution in PVP with average size of ± nm (Figure 3.48) When concentrations of reducing agent increased to 0.5 and 0.7 M, the copper nanoparticles forming has large size with the average diameter in range of 15 ± nm (Figure 3.49) and 22 ± nm (Figure 3.50) respectively a Effect of the amount of trisodium citrate Figure 3.53 to 3.55 are the result of TEM images that shown the effect of the amount of trisodium citrate to the synthesis of copper nanoparticles The results shown that, the copper nanoparticles were created with average diameter in range of 20 ± nm when the sample were prepared without trisodium citrate (Figure 3.53) However, the particles still tend to form larger particles and on the surface of larger particles has the agglomeration of smaller particle Synthetic form trisodium citrate from rate / CuCl2 = 12 0.1 and 0.5, the nano copper particles formed have a smaller average size, with corresponding values of 17 ± nm (Figure 3:54) and ± nm (Figure 3:55) Figure 3.53: TEM image and particle size distribution of CuNPs were synthesized with ratio trinatri citrat/CuCl2 = 0,10 Figure 3.54: TEM image and particle size distribution of CuNPs were synthesized with ratio trinatri citrat/CuCl2 = 0,10 Figure 3.55: TEM image and particle size distribution of CuNPs were synthesized with ratio trinatri citrat/CuCl2 = 0,50 d Effect of the ratio of CuCl2/ PVP in the presence of trisodium citrate UV-Vis spectrum of the copper nanopaticles colloidal solution is presented in Figure 3.58 The results shown that, when the ratio of CuCl2/ PVP increased (from to 5%), the intensity of absorbance peak increased However, the change of position of the absorption peak shifted only from 562 to 564 nm As the ratio of CuCl2/ PVP increased to and 7%, the position of surface plasmon absorbance peak were 567 and 572 nm respectively Thus, it can be predicted that the copper nanoparticles were prepared in small size when ratio of CuCl2/ PVP changed from to %, However, the copper nanoparticles forming increased when the ratio of CuCl2/ PVP increased to and %, These results will be verified by TEM images Figure 3.58: UV-Vis spectra of copper nanopaticles were synthesized with the ratio of CuCl2/ PVP from to % Figure 3.59: TEM image and particle size distribution of CuNPs were synthesized with ratio CuCl2/PVP = % Figure 3.55 and 3.59 are TEM images of the copper nanopaticles were synthesized by using the ratio of CuCl2/ PVP and % The results shown that, copper nanoparticles forming had uniform distribution in spherical with average size ± nm and ± nm respectively This result was consistent with the absorption peaks from the effects of surface plasmon resonance of copper nanoparticles in small size as shown in the UV-Vis spectrum in Figure 3:58 13 e Investigating of the synthesis of copper nanoparticles in the presence of trisodium citrate in PVA capping agent The best parameters for the synthesis of copper nanoparticles with protective agent PVP were used to synthesis of copper nanopaticles with protective agent PVA (Mw = 60,000 g/ mol) as follows: PVA 0,2 g; temperature at 110 °C, the concentration of HH 0.2 M; trisodium citrate was determined to ensure ratio of trisodium citrate/ CuCl2 = 0.5 CuCl2 was determined to ensure ratio of CuCl2/ PVA = 5, 7% Figure 3.61: UV-Vis spectra of copper nanopaticles were synthesized with ratio of CuCl2/PVA = % (curve 1) and % (curve 2) Figure 3.62: TEM image and particle size distribution of CuNPs were synthesized with ratio CuCl2/PVA = % Figure 3.63: TEM image and particle size distribution of CuNPs were synthesized with ratio CuCl2/PVA = 7% Figure 3.61 was UV-Vis spectrum of the copper nanopaticles which were synthesized by using CuCl2/PVA = 5%, 7% The results shown that, copper nanoparticles had surface plasmon absorbance peaks at short wavelength Specially, the absorbance peak appeared at 558 nm wavelength with ratio of CuCl2/ PVA = % The absorbance peak shifted to longer wavelength at 562 nm with ratio of CuCl2/ PVA = 7% Thus, the effect of surface plasmon resonance allows predicted that copper nanoparticles were created in ultra-sized ( nm) and low concentration of copper nanoparticles were obtained in this procedure From copper nitrate and copper chloride (chemical reduction method with hydrazine hydrate as reducing agent), the small-size (3 nm) and high concentration [Cu(NO3)2/PVP = 13 %] of copper nanoparticles were produced by using PVP (Mw: 1,000,000 g / mol) and TSC as protective agents The small-size (3 nm) and high concentration (CuSO4/PVP = 11%) of colloidal solutions with high stability were prepared in water by using AA, CTAB and PVP as protective agents The optical properties, surface structure of the copper nanoparticles material were characterised by the XRD, UV-Vis and TEM analysis results The change of copper nanoparticle size by using TEM with the shift UV-Vis absorption peaks fit perfectly Biological properties of copper nanoparticles were exhibited in antifungal activity and high killing ability against Corticium salmonicolor at low concentrations REQUEST Synthesis of copper nanoparticles colloidal solution with stability at high concentrations Deploying the application of copper nanoparticles in the fields of agriculture, antifungal to pathogenic plant 24