Development and Modification of Porous Polymer Structures in the Vicinity of Cellulose Fibers

Abstract

In this work, hierarchically porous materials have been prepared by the self-assembly and pore formation of different amphiphilic block copolymers (BCPs) in the vicinity of cellulose paper sheets. For this, polystyrene-block-polysolketal methacrylate (PS-b-SMA) as a linear BCP and polymethyl methacrylateblock-polysolketal methacrylate (PMMA-b-SMA) n as a star-shaped BCP were prepared using living anionic polymerization. Under a mild acidic environment, the amphiphilic properties were revealed by converting the PSMA block segment to poly(dihydroxypropyl methacrylate) (PDHMPA). The BCPs were incorporated onto the Linter's fiber-based cellulose sheets by a self-assembly and nonsolvent-induced phase separation (SNIPS) process. The received porous materials have been further modified with 3aminopropyltriethoxysilane (APTES) and 3,3,3-trifluoropropyl dimethyl chlorosilane (TFPCS) using vapor-phase modification. This strategy enabled tuning the surface properties of the porous structures received to adjust surface polarity further. The characteristics of the porous modified materials were confirmed at the microscopic scale by solid-state nuclear magnetic resonance (NMR) combined with selectively enhanced dynamic nuclear polarization (DNP), and Fourier transform infrared (FTIR) spectroscopy. The influence of APTES and TFPCS was further analyzed at the macroscopic level using water contact angle (WCA) measurements and water permeance testing, in which changes were observed for both modifiers. Using this convenient strategy, the fabrication of functional porous cellulose composite materials is demonstrated, paving the way for a new family of cellulose-based porous materials.