Interface interaction within nanopores in thin films of an amphiphilic block copolymer and CTAB

With water droplets as sacrificed templates at a particular humidity, micro-porous solid thin films were successfully fabricated by self-assembly using an amphiphilic block polymer, polystyrene-b-polyacrylic acid (PS-b-PAA). Interface interactions between the micro-porous thin film and a cationic surfactant, cetyltrimethylammonium bromide (CTAB), are investigated by in-situ AFM in aqueous solutions. An interesting phenomenon was observed in water and CTAB solution, which the dimensions of the micropores are remarkably larger than the dimensions of those in air. The solid thin films exhibit different surface morphologies in response to stimulus by different concentrations of CTAB. These observations were explained by positing that the PAA chains in the micropores stretch and contract with interface interactions between PAA and CTAB. A promising electrochemical application of this film is suggested. This study is aimed at strategies for the functionalization of stimulus-responsive micro-porous solid thin films with tunable surface morphologies, and exploring new smart materials.

Interface interactions between a solid thin micro-porous film of an amphiphilic diblock copolymer formed by self-assembly and a cationic surfactant are investigated by in-situ atomic force microscopy.Figure optionsDownload high-quality image (76 K)Download as PowerPoint slideResearch highlights
► Morphological investigations of microporous copolymer film interacting with CTAB.
► AFM technology applied to observe in-situ surface morphological changes.
► Dynamic light scattering (DLS) results and electrochemical behaviors of a Pt ultra-microelectrode modified by the microporous thin film.