Adsorption of a cholesteric liquid crystal polyester on silver nanoparticles studied by surface-enhanced Raman scattering and micro Raman spectroscopy.

A Raman study of the adsorption of thermotropic cholesteric liquid crystal polyester PTOBDME ([C(34)H(36)O(8)](n)) on Ag surfaces is presented in this work. The affinity and adsorption mechanism of this polymer was tested on Ag metal colloids and on Ag films obtained by direct immobilization of the colloidal nanoparticles. We have first studied the structure of PTOBDME suspended in several solvents in order to identify the Raman bands used as structural markers. The adsorption of the polymer leads to a deep conformational change involving both the main chain and the aliphatic side chain. The interaction of polymers like PTOBDME with metals could be interesting in the formation of functionalized surfaces, providing them with specific physicochemical properties with possible applications in recognition phenomena, which can be easily characterized by Raman spectroscopy.