Photo-initiated thiol-ene click reaction with 1-octadecanthiol in the presence of free radical initiator, 2,2-dimethoxy-2-phenylacetophenone, has been applied for pore surface modification of photopolymerized sol-gel monoliths prepared from 3-(trimethoxysilyl)propyl methacrylate. This functionalization was carried out to increase the hydrophobicity of the parent monolith with an aim to enhance the suitability of the material for separations in reversed-phase liquid chromatography. Initially, the effects of the monomer concentration in the reaction mixture and the type of initiator including 2,2-dimethoxy-2-phenylacetophenone and benzophenone were examined. The chromatographic performance of the modified columns was tested in terms of column efficiency and retention of alkylbenzenes. In addition to 1-octadecanthiol, the click reaction was carried out with two more alkylthiols, 1-hexanthiol and 1-dodecanthiol. An increase in the length of alkyl group of thiol resulted in increased retention of alkylbenzenes, confirming an increase in surface hydrophobicity of the monolith. The performance of monoliths functionalized using the thiol-ene click chemistry was found superior to performance of monolithic column prepared via photografting with octadecyl methacrylate.

Surface modification of photopolymerized sol-gel monoliths using thiol-ene click chemistry

249th National Meeting (2015)

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