Temperature assisted reorganization of silver nanoparticles in free-standing, flexible chitosan functionalized reduced graphene oxide thick films: A potential SERS probe for folic acid sensing

Publication date: February 2020Source: Materials Science and Engineering: B, Volume 252Author(s): S. Asha, A. Nimrodh Ananth, Sujin P. Jose, Michael Anjello Jothi RajanAbstractChitosan and silver functionalized free standing reduced graphene oxide (rGO) films were prepared using simple soak and dry strategy. Redistribution of silver aggregates on chitosan functionalized rGO films were observed by thermally annealing these films at 450 °C, in an inert atmosphere. The re-organization / redistribution of silver aggregates in the rGO films were studied using in-situ Raman scattering signals. The redistribution of silver particles occurs through melting of micron sized silver aggregates during annealing. The rearrangement of the micro-sized silver aggregates to spherical silver nanoparticle on chitosan functionalized rGO film, as a result of temperature was assisted through factors such as graphene surface ripple rearrangement and the denaturation of rGO surface interacting chitosan chains. These free-standing films with redistributed silver nanoparticles showed excellent surface enhanced Raman scattering (SERS) effect with enhanced Raman signals for folic acid sensing, showcasing its potentiality to be utilized as flexible SERS based sensors.Graphical abstract
Source: Materials Science and Engineering: B - Category: Materials Science Source Type: research