Gel Emulsion Based on Amphiphilic Block Copolymer: A Template to Develop Porous Polymeric Monolith for the Efficient Adsorption of Volatile Organic Compounds

The fabrication of adsorbents for volatile organic compounds (VOCs) always attains significant research interest for the industrialized civilization. Herein, we report the fabrication of a new class of porous polymeric monolith for the efficient adsorption of VOCs. In this case, a gel emulsion stabilized by poly(oligo(ethylene glycol) methyl ether methacrylate)-b-polystyrene (POEGMA-b-PS), an amphiphilic block copolymer (BCP), was successfully used as the template for the development of a porous monolith having a porosity in the range of 5–50 μm. A reversible addition–fragmentation chain transfer (RAFT) polymerization technique was adopted for the synthesis of BCP with varying PS block length. The BCPs were used as the stabilizer for water-in-oil gel emulsion consisting of >90% dispersed phase without using any costabilizer. Morphology and thermal and rheological behavior of the prepared gel emulsions were found to be dependent on the PS block length in the BCP as analyzed in FE-SEM, DSC, and rheometry. Porous polymeric monoliths were prepared by polymerizing gel emulsions with a mixed oil phase containing a styrene monomer, cross-linker, and radical initiator. The resulting monoliths had a minimum density of 0.08 g/cm3. Those monoliths were found to have very high resistance to water, showing a water contact angle of ∼120°, while they can effectively adsorb a wide range of VOCs like benzene, toluene, xylene, ethylbenzene, chloroform, tetrahydrofuran, acetone, formaldehyde, hexane, etc. and also attain reusability with similar efficiency.