Gel-emulsions prepared using a low-molecular-weight gelator and their use in the synthesis of porous polymers

Abstract

Water-in-oil (W/O) gel-emulsions consisting of water and a monomer were successfully prepared using N-3-hydroxypropylcarbonyl-L-isoleucyl-aminooctadecane as a gelator. Low-temperature polymerization of the gel-emulsions with a redox initiator was performed to obtain the corresponding porous polymers. Furthermore, polymerization of gel-emulsions containing bifunctional monomers gave crosslinked porous PMMA-HDODA, PMMA-EGDMA, PMMA-DVB, and PSt-DVB, which were found to be mechanically robust and solvent resistant. The microstructures of the porous polymers and crosslinked porous polymers were observed by scanning electron microscopy. The adsorption capacities of the polymers toward methanol, dichloromethane, acetone, tetrahydrofuran, toluene, hexane, and kerosene were assessed and rationalized in terms of the surface microstructures of the polymers. The time courses of the adsorptions were investigated, revealing a two-step adsorption process comprising rapid permeation into the cavities of the porous polymers followed by a slow swelling step. The high water-repellency of the crosslinked porous polymers was confirmed by contact angle measurement. The reusabilities of the polymers as solvent absorbents were evaluated through repeated adsorption and drying. Water-in-oil (W/O) gel-emulsions consisting of water and a monomer were successfully prepared using N-3-hydroxypropylcarbonyl-L-isoleucyl-aminooctadecane as a gelator. Low-temperature polymerization of the gel-emulsions with a redox initiator was performed to obtain the corresponding porous polymers. Polymerization of gel-emulsions containing bifunctional monomers gave crosslinked porous polymers, which were found to be mechanically robust and solvent resistant. The adsorption capacities of the polymers toward several liquids were assessed and rationalized in terms of the surface microstructures of the polymers. The time courses of the adsorptions were investigated, revealing a two-step adsorption process comprising rapid permeation into the cavities of the porous polymers followed by a slow swelling step.