Structure and Phase Transition in Thin Films of Semifluorinated

Abstract

An approach for preparing the ordered structures of Au/polymer nanocomposites is discussed, which employs solvent vapor, supercritical CO2 and thermal annealing process for Au-loaded poly(1H,1H-dihydroperfluorooctyl methacrylate)-b-poly(ethylene oxide) (PFOMA-b-PEO) and Au-loaded poly(3-hexylthiophene)-b-poly(1H,1H- dihydroperfluorooctyl methacrylate) (P3HT-b-PFOMA) thin films. Semifluorinated diblock copolymers PFOMA10k-b-EO12k was prepared by atom transfer radical polymerization (ATRP), and its micellar solution with a gold precursor, LiAuCl4, in chloroform was spin-coated onto substrate to produce thin hybrid films. After annealing, the chains were reorganized and formed spherical copolymeric films. The nanoparticles were forced to follow the morphological change and were transformed into a larger single particle in each PEO domain. In the case of P3HT4k-b-PFOMA14k, the block copolymers underwent microphase separation and self-assembly into well-defined and organized nanofibrillar-like morphology from their micelle solution. The gold nanoparticles were stabilized by the interaction of the sulfur atoms of P3HTs with the gold surface and they dispersed in the P3HT phase. The length of nanofibrils increased a little with pronounced branching after thermal annealing, solvent annealing and scCO2 annealing in the micellar films with the Au nanoparticles.