Preparation and properties of nanocomposite hydrogels containing silver nanoparticles by ex situ polymerization

2006 ◽  
Vol 100 (5) ◽  
pp. 3653-3661 ◽  
Author(s):  
Wen-Fu Lee ◽  
Kai-Tai Tsao
2012 ◽  
Vol 585 ◽  
pp. 134-138 ◽  
Author(s):  
Alisha Goyal ◽  
Jyoti Rozra ◽  
Isha Saini ◽  
Pawan K. Sharma ◽  
Annu Sharma

Nanocomposite films of Poly (methylmethacrylate) with different concentration of silver nanoparticles were prepared by ex-situ method. Firstly, silver nanoparticles were obtained by reducing the aqueous solution of silver nitrate with sodium borohydride then Ag-PMMA films were prepared by mixing colloidal solution of silver nanoparticles with solution of polymer. Thin solid films were structurally characterized using UV-VIS spectroscopy and TEM. The appearance of surface plasmon resonance peak, characteristic of silver nanoparticles at 420 nm in UV-VIS absorption spectra of Ag-PMMA films confirms the formation of Ag-PMMA nanocomposite. TEM showed Ag nanoparticles of average size 8 nm embedded in PMMA matrix. Analysis of absorption and reflection data indicates towards the reduction in optical band gap and increase in refractive index of the resulting nanocomposite. The synthesized Ag-PMMA nanocomposite has been found to be more conducting than PMMA as ascertained using I-V studies. The decrease in band gap and increase in conductivity can be correlated due to the formation of localized electronic states in PMMA matrix due to insertion of Ag nanoparticles. The PMMA thin films with dispersed silver nanoparticles may be useful for nanophotonic devices.


2011 ◽  
Vol 23 (1) ◽  
pp. 99-107 ◽  
Author(s):  
Bojana Obradovic ◽  
Jasmina Stojkovska ◽  
Zeljka Jovanovic ◽  
Vesna Miskovic-Stankovic

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4793
Author(s):  
Adrian Ionut Nicoara ◽  
Alexandra Elena Stoica ◽  
Denisa-Ionela Ene ◽  
Bogdan Stefan Vasile ◽  
Alina Maria Holban ◽  
...  

Hydroxyapatite (HAp) and bacterial cellulose (BC) composite materials represent a promising approach for tissue engineering due to their excellent biocompatibility and bioactivity. This paper presents the synthesis and characterization of two types of materials based on HAp and BC, with antibacterial properties provided by silver nanoparticles (AgNPs). The composite materials were obtained following two routes: (1) HAp was obtained in situ directly in the BC matrix containing different amounts of AgNPs by the coprecipitation method, and (2) HAp was first obtained separately using the coprecipitation method, then combined with BC containing different amounts of AgNPs by ultrasound exposure. The obtained materials were characterized by means of XRD, SEM, and FT-IR, while their antimicrobial effect was evaluated against Gram-negative bacteria (Escherichia coli), Gram-positive bacteria (Staphylococcus aureus), and yeast (Candida albicans). The results demonstrated that the obtained composite materials were characterized by a homogenous porous structure and high water absorption capacity (more than 1000% w/w). These materials also possessed low degradation rates (<5% in simulated body fluid (SBF) at 37 °C) and considerable antimicrobial effect due to silver nanoparticles (10–70 nm) embedded in the polymer matrix. These properties could be finetuned by adjusting the content of AgNPs and the synthesis route. The samples prepared using the in situ route had a wider porosity range and better homogeneity.


2016 ◽  
Vol 294 (12) ◽  
pp. 2021-2028 ◽  
Author(s):  
Daoyi Jiang ◽  
Yanyan Zhang ◽  
Fangmin Zhang ◽  
Zhixiong Liu ◽  
Jin Han ◽  
...  

2016 ◽  
Vol 40 (8) ◽  
pp. 6650-6657 ◽  
Author(s):  
Haoyang Jiang ◽  
Gongzheng Zhang ◽  
Bo Xu ◽  
Xianqi Feng ◽  
Quanming Bai ◽  
...  

Clay nanosheets act as a catalyst and stabilizing agent for rapid in situ synthesis of silver nanoparticles in a hydrogel matrix.


2021 ◽  
Author(s):  
◽  
Kerstin Ann Burridge

<p>Significant opportunities exist in both the scientific and industrial sectors for the development of novel multi-functional materials that combine the inherent properties of all precursor components in a synergistic manner, thereby providing new products and opportunities. Processes that add value to natural materials in a facile and refined manner are particularly sought after. Thus this research combines useable substrates, notably natural protein fibres and minerals with gold or silver nanoparticles, producing high value, multi-functional materials that display the strength, softness and shine (of the protein fibres), or high surface area and dispersibility (of the minerals) with the high value and wealth associated with the noble metal nanoparticles, their broad spectrum of intense colours, anti-microbial, insecticide and anti-static properties. This adds significant worth to the substrates, transforming them from commodities to valuable materials.  Silk, merino wool and crossbred wool were the natural fibres employed kaolinite and halloysite clays the minerals. They were combined with gold and silver nanoparticles of various sizes and shapes (and hence colours) producing the following composite materials:  • Gold nanoparticle-merino wool composites  • Gold nanoparticle-crossbred wool composites  • Gold nanoparticle-silk composites  • Silver nanoparticle-kaolinite composites  • Silver nanoparticle-halloysite composites  The most successful method for producing silver nanoparticle-clay composites involved the external preparation of silver nanoparticles and their subsequent attachment to the clay substrates by means of a layer-by-layer deposition approach, which capitalised on electrostatic interactions between oppositely charged polyelectrolytes capping the nanoparticles and bound to the clay surfaces.  Three general approaches were employed in the production of the gold nanoparticle-natural fibre composite materials. The nanoparticles were either synthesised ex-situ and subsequently attached to the fibres, or the natural fibres were utilised as redox active biotemplates in which the wool or silk absorbed and subsequently reduced Au³⁺ to nanoparticulate Au⁰ on and within the fibres. Thirdly, a seed mediated growth approach was employed in which additional Au³⁺ was reduced to nanoparticulate Au⁰ on the surface of gold nanoparticles already bound to the fibres. This was facilitated by an external reductant.</p>


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