A new strategy for simultaneous synthesis and efficient anchorage of polymer monoliths in native PDMS microchips

We report here a one-pot approach to achieve, for the first time, the simultaneous synthesis/anchorage of polymer monoliths in native PDMS channels. Monoliths consisting of ethylene glycol methacrylate phosphate (EGMP) and N,N'-methylene-bis-acrylamide (BAA) were synthesized within PDMS microchips through a photo-driven process. The EGMP monomer has never been employed for this purpose. To achieve this method, both the chemical nature of the photoinitiator and irradiation conditions were investigated. The main result was that the use of 2-methyl-4'-(methylthio)-2-morpholino-propiophenone, as photoinitiator, allowed simultaneous polymerization and anchorage of the resulting monolithic structure onto the PDMS channel. Morphology of the monolith revealed a compact structure composed of uniform nodules (135 +/- 30 nm) and small pores (10-200 nm). The high specific surface area (66 m(2)/g) and the sufficient permeability (14.35 x 10(-14) m(2)) obtained make the monolith particularly interesting for preconcentration. Such free radical-mediated method open new perspectives for preconcentration and electrophoretic separation in PDMS microsystems. (C) 2015 Elsevier Ltd. All rights reserved.