Synthesis and characterization of novel silver/L-phenylalanine-based optically active polyacrylate nanocomposite (original) (raw)
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Journal of Polymer Research, 2012
Poly(acrylic acid)/Silver, PAA/Ag, nanocomposite, was in-situ synthesized by radical polymerisation of acrylic acid (AA) monomers, using AIBN as initiator and ethanol as solvent in presence of silver nitrate AgNO 3 nanoparticles. It was found that polymerisation of (AA) monomers and reduction of silver ions occurred simultaneously, thereby leading to the formation of the PAA/Ag nanocomposite. The obtained material was characterized by infrared (IR), UV-visible, photo-luminescence measurements, X-Ray powder diffraction (XRD), and scanning electron microscopy (SEM). Strong interactions between silver ions and carboxylic groups of PAA, were identified by FT-IR spectroscopy. Highly luminescent single colloidal silver nanoparticles under blue excitation were detected by photoluminescence spectroscopy. Scanning electron microscopy (SEM), image revealed that silver nanoparticles were well dispersed in PAA matrix. X-ray powder diffraction XRD pattern, showed the appearance of small picks corresponding to the face centred cubic (f.c.c.) silver phase. Furthermore the antimicrobial activity of Ag nanoparticles was investigated against, Staphylococcus aureus and Candida albicans microorganisms. It was found that the carboxylic groups from the acrylic acid favour silver ions mobility in the organic matrix. Thus they are expected to be liable to the enhancement of the antimicrobial surface activity in this hybrid material. The results suggest that PAA/ Ag nanocomposite can be used as effective growth inhibitors in various microorganisms , making them appropriate to diverse medical devices and antimicrobial control systems.
New silver nanoparticle (AgNP)-loaded amino acid based hydrogels were synthesized successfully from poly (vinyl alcohol) (PVA) and poly(acryl amide-co-acryloyl phenyl alanine) (PAA) by redox polymerization. The formation of AgNP in hydrogels was confirmed by using a UV-Vis spectrophotometer and XRD. The structure and morphology of silver nanocomposite hydrogels were studied by using a scanning electron microscopy (SEM), which demonstrated scattered nanoparticles, ca. 10-20 nm. Thermogravimetric analysis revealed large differences of weight loss (i.e., 48%) between the prestine hydrogel and silver nanocomposite. The antibacterial studies of AgNP-loaded PAA (Ag-PAA) hydrogels was evaluated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria. These Ag-PAA hydrogels showed significant activities against all the test bacteria. Newly developed hydrogels could be used for medical applications, such as artificial burn dressings.
Polymer Bulletin, 2016
Poly(acrylic acid), PAA, has been mixed in solution with silver nanoparticles, obtained by chemical reduction of silver nitrate. Two different sulfurcontaining organic compounds have been used as stabilizers of Ag nanoparticles: mercaptosuccinic acid (MSA) and 3-mercaptopropionic acid (MPA). The formation of Ag nanoparticles has been monitored by UV-Vis spectroscopy. The morphology and composition of obtained nanomaterials has been studied by electron microscopy techniques (SEM/EDX and HR-TEM). Nanomechanical properties of nanocomposites (adhesion and nanohardness) have been investigated by Atomic Force Microscopy (AFM). Thermal stability has been determined using thermogravimetric analysis. The exposure of specimens to UV radiation allowed to observe the changes in the nanoparticle structure and to estimate nanocomposite photostability. MSA has proved to be a better stabilizer of Ag nanoparticles immediately after the synthesis, when MPA provides better storage stability. MPA has allowed for the creation of nanoparticles using mixed reduction (chemical/photochemical) of AgNO 3. It has been found that the nanocomposite materials are stable for 12 months of storage in solution and in solid form.
Photochemical stability of poly(acrylic acid)/silver nanocomposite
Materials Letters, 2014
Ag nanoparticles, stabilized by mercaptosuccinic acid (MSA), have been obtained by chemical reduction of silver nitrate. The nanocomposites of poly(acrylic acid) (PAA) with Ag have been prepared by casting of aqueous polymer solutions and water evaporation. The influence of polychromatic UV-irradiation on PAA/Ag/MSA nanocomposite properties was determined by UV-vis and FTIR spectroscopy. The mean size of the formed Ag nanoparticles has been estimated by dynamic light scattering (DLS). The studied Ag nanoparticles coated by MSA were stable during one year storage and theirs stability was better in neutral solution than in alkaline one. It was found that PAA/Ag/MSA system is more resistant to UV radiation than virgin PAA, which is caused by efficient photocrosslinking.
Polymer, 2001
Polyacrylonitrile (PAN)/silver (Ag) nanoparticle composites were in-situ synthesized by ultraviolet irradiation of a mixture of silver nitrate (AgNO 3 ) and acrylonitrile (AN) monomers. The resultant composites were characterized by infrared spectroscopy (IR), X-ray powder diffraction (XRD) and high-resolution transmission electron microscopy (TEM). It was found that polymerization of AN monomers and reduction of silver ions occurred simultaneously, thereby leading to the formation of the PAN/Ag composites. TEM image revealed that silver nanoparticles with a diameter ranging from 5 to 10 nm were well dispersed in PAN matrix. It was found from the reaction mechanism that the complex of silver ions with AN monomers provided an excellent precursor for this synthesis, which is responsible for homogeneous dispersion and narrow size distribution of silver nanoparticles. q
Polymer International, 2011
Poly(4-aminodiphenylamine)-silver nanocomposites were synthesized by an easy one-step aqueous chemical oxidative polymerization of 4-aminodiphenylamine (4ADPA) using silver nitrate (AgNO 3) as the oxidant. Two different structure directing surfactants, p-toluene sulfonic acid (p-TSA) and cetyl trimethyl ammonium bromide/hydrochloric acid (CTAB/HCl), were independently used for the nanocomposite (NC) preparation. The NCs prepared in p-TSA and CTAB/HCl medium were designated as P4ADPA/AgNC (p−TSA) and P4ADPA/AgNC (CTAB/HCl) , respectively. We investigated the morphological variations in the NCs based on the medium. P4ADPA/AgNC (p−TSA) and P4ADPA/AgNC (CTAB/HCl) were characterized by field emission scanning electron microscopy, X-ray diffraction analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis and UV-visible spectroscopy.
Polymers
A chemical method was successfully used to synthesize silver nanoparticles (AgNPs) with various shapes. The shape of the nanoparticles affects the color of the colloid (spherical—yellow solution, triangular—blue, a mixture of spherical and triangular—green). The NaBH4, which acts as the main reducing agent and H2O2 have a significant impact on the shape of AgNPs. It has also been shown that the ratio between precursor, reducing, and the stabilizing agent is crucial for the formation of the required nanoparticles. The light sensitivity of AgNPs and the presence of H2O2 lead to a significant change in AgNPs’ shape and size with time and to the formation of the dichroic effect. UV–vis spectrophotometry, TEM, SEM/FIB, and EDX methods were used to analyze the shape, size, and composition of the nanoparticles. Polymer matrix composite with AgNPs was prepared by the “ex-situ” method.
An in-situ simple method is used to prepare polyacrylic acid (PAA) silver nanocomposite. Chemical reduction method by using mixture of sodium borohydride (NaBH 4 ) and ascorbic acid (AA) are utilized to reduce silver nitrate and generate Ag-NPs in the PAA matrix while sodium tri-citrate is employed to stabilize the prepared colloid. Furthermore, thin film of PAA embedded with Ag nano-particles is deposited by using electrospray deposition technique (ESD). The obtained colloid and film were characterized by using UV-visible, FT-IR, TEM, and AFM. UV-vis spectroscopy showed an absorption peak at 425 nm which is attributed to the well-known surface plasmon resonance of the Ag-NPs. The interaction between Ag + and PAA carboxylic groups is investigated by FT-IR. TEM images showed the well dispersion of Ag-NPs in the PAA matrix with average particle size of 7 nm. The Ag-NPs released from the polymer matrix proven to have a significant antimicrobial activity against E. coli, S.aureus, B.subtilis and C.albicans.
Facile synthesis of polyacrylate directed silver nanoparticles for pH sensing through naked eye
Journal of Macromolecular Science, Part A, 2019
Poly(acrylic acid) (PAA) and its salt poly(acrylate) (PA) have been synthesized through modified free radical polymerization in environmentally begin aqueous medium under ultrasound to make the process robust. The synthesized polymer is well-characterized through conventional techniques. Its salt is employed to produce highly stable and stimuli sensitive colloidal silver (Ag-PA sol) without using any additional reducing chemical reagents like sodium borohydride, ascorbic acid, hydrazine, etc or UV/Gamma radiation. A detailed mechanistic path of the polymerization and reduction of Ag þ on polyacrylate chains has been evaluated. Finally Ag-PA sol is used for pH sensing through naked eye to eliminate the need for sophisticated instrument for data collection. The present work focuses mainly the development of a low cost pH sensing system based on colorimetric 'smart polymer' having high practical utility. The unique structural and photo-physical features of nano-scaled materials open new opportunities for the applications of colorimetric pH sensor. In the present work, Ag nano-clusters capped by PA À are employed as an effective colorimetric pH sensor for the first time, requiring no further functionalization.
Polymer, 2010
A silver-acrylate nanocomposite was prepared using a novel one-pot strategy involving eosin dye as visible sensitizer and an amine derivative as radicals' source. The mechanism highlighted by steady state photolysis and time-resolved absorption spectroscopy lies on the initial formation of a strong ion-pair complex between eosin and Ag þ . Upon visible irradiation, the excited triplet state of the metal complex efficiently abstracts a hydrogen atom from the amine and produces an a-aminoalkyl radical. In acrylate monomer matrix, such a strong reactive species initiates a free radical photopolymerization and also provides the reduction of the silver cation. Through this 'in-situ' fabrication method, the kinetics formation of the nanocomposite and its detailed structural analysis are characterized by UV-visible, realtime FTIR absorption spectroscopy and by transmission electron microscopy.