Preparation And Properties Of Silver Nanoparticles And Silver Nanoclusters/Biopolymer Nanocomposite

Biopolymers are the most abundant materials that can be obtained from natural sources and have a number of advantages such as the biocompatibility,biodegradability,non-toxicity,environmental friendliness and renewability.In recent years,researchers have paid much attention to biopolymer electrodeposition,which has been applied in biosensors,enzyme immobilization,coatings,fuel cells.Silver nanoparticles(AgNPs)and silver nanoclusters have attracted extensive research interest due to their unique optical,electrical and catalytic properties.Some biopolymers can be used as the green reducing agent and the stabilizing agent for preparing AgNPs,and also as the template and the reducing agent for preparing silver nanoclusters.Moreover,the nanocomposites of AgNPs or silver nanoclusters and biopolymers show important applications in antibacterial biomaterials,conductive materials,supercapacitors,biosensors.In this paper,the electrodeposition of carboxylated chitosan is studied and utilized for the synthesis of AgNPs and generation of AgNPs/carboxylated chitosan nanocomposite films.Particularly,AgNPs are in situ synthesized on electrodes or substrates during the electrodeposition.Carboxylated chitosan not only acts as the green reducing agent and stabilizing agent for preparing AgNPs,but also serves as the main component in the electrodeposited nanocomposite film.Therefore,this paper establishes a novel method for the synthesis of metal nanoparticles based on biopolymer electrodeposition technology,and provides a simple and controllable method for the direct preparation of metal nanoparticles and biopolymer nanocomposite film.This paper also explores a new method for preparing silver nanoclusters/carboxymethyl cellulose nanocomposite films based on biopolymer electrodeposition.In this method,the carboxymethyl cellulose serves as the green reducing agent and the template.The silver nanoclusters/carboxymethyl cellulose nanocomposite films can be directly obtained on electrodes or substrates by using coordinated electrodeposition of carboxymethyl cellulose.In addition,a silver nanoclusters/gelatin nanocomposite with thermo-responsive sol-gel transition property is prepared for the first time in this paper.The nanocomposite shows clear red fluorescence.Silver nanoclusters/gelatin nanocomposite gels with different shapes can be prepared using the thermo-responsive sol-gel transition property.The release of silver nanoclusters can also be controlled by the thermo-responsive sol-gel transition.Furthermore,the thermo-responsive sol-gel transition causes a significant change on the fluorescence intensity of the silver nanoclusters/gelatin nanocomposite.In this paper,the simple,controllable,mild and green methods are developed for preparing silver nanoparticles and silver nanoclusters and their nanocomposites.In addition,the silver nanoclusters/gelatin nanocomposite with the thermo-responsive sol-gel transition property is prepared.This paper provides new methods for the synthesis of silver nanoparticles and silver nanoclusters,and for the construction of silver nanoparticles and silver nanoclusters/biopolymer nanocomposites.The resulting silver nanoparticles or silver nanoclusters/biopolymer nanocomposites exhibit potential applications in nanocomposite materials,functional film materials and bioelectronic devices.