Control of the chemistry outside the pores in honeycomb patterned films

Abstract

We report the selective functionalization of the external surface in honeycomb structured porous films while maintaining the functionality of the pores. For this purpose, we describe the preparation of polymer films from blends of polystyrene (PS) and polystyrene-b-poly(2,3,4,5,6-pentafluorostyrene) (PS-b-P5FS) by the breath figures approach. The diblock copolymer resulted to be homogeneously distributed along the whole surface of the films as a consequence of the reorientation towards the solution–air interface. The porous films obtained have a wetting behavior that can be described by the Cassie–Baxter state equations. This particular effect allowed us to modify the chemical composition of the film surface whilst the interior of the pores does not vary. As a proof of concept, we report the modification of the surface using “click” chemistry. Thiolated glucose molecules were attached specifically to the poly(2,3,4,5,6-pentafluorostyrene) domains via thiol-para fluorine “click” reaction. The kinetics of this reaction and the possibility to participate in recognition processes have been evaluated by contact angle measurements, X-ray photoelectron spectroscopy and fluorescence microscopy.