Polymer nanocomposites based on gold nanoparticles: Synthesis, properties and applications

Polymer nanocomposites have great potential in materials science research for different applications in the fields of industrial engineering, catalysis, sensing, biology, and medicine. Nanocomposites based on polymers and gold nanoparticles (AuNPs) combine the mechanical properties and processability of polymers with the electrical, plasmonic, and catalytic properties of the AuNPs. Various synthetic approaches can be used to produce these nanocomposites, such as the colloidal synthesis of AuNPs with reducing agents (sodium borohydride, sodium citrate) and the direct mixing of the presynthetized polymers; and electrochemical route by oxidative electropolymerization of monomers and reduction of gold salts. Usually, the final composite can be characterized by electron microscopy and spectroscopic techniques. A wide range of nanocomposites can be prepared through physical (adsorption) or chemical (covalent bond) interactions between polymers and nanoparticles, resulting in unique properties. To illustrate, the incorporation of metallic nanoparticles in conducting polymers can promote a synergistic effect, increasing the individual performance of the composite for applications in electrocatalysis, sensors and biosensors, energy storage devices, and solar cells. Natural polymers such as polysaccharides can interact with AuNPs, acting as a nontoxic reducing agent and/or stabilizer, increasing their biocompatibility and expanding their use in nanomedicine applications. Biopolymers bring their biodegradability, biocompatibility, low toxicity, and cost-effectiveness advantages into the nanocomposites, further improving applications in nanomedicine such as controlled release and tissue engineering. In this chapter, different syntheses of polymer and gold nanoparticle composites were explored. The chapter also focuses on composite properties, mainly optical, electrochemical, and biocompatibility, and the possible characterization methods, evidencing the versatility in the application of these materials.