Facile synthesis and responsive behavior of PDMS-b-PEG diblock copolymer brushes via photoinitiated "thiol-ene" click reaction

We present herein a mild and rapid method to create diblock copolymer brushes on a silicon surface via photoinitiated thiol-ene click reaction. The silicon surface was modified with 3-mercaptopropyltrimethoxysilane (MPTMS) self-assembled monolayer. Then, a mixture of divinyl-terminated polydimethylsiloxane (PDMS) and photoinitiator was spin-coated on the MPTMS surface and exposed to UV-light. Thereafter, a mixture of thiol-terminated polyethylene glycol (PEG) and photoinitiator were spin-coated on the vinyl-terminated PDMS-treated surface, and the sequent photopolymerization was carried out under UV-irradiation. The MPTMS, PDMS, and PEG layers were carefully identified by X-ray photoelectron spectroscopy, atomic force microscopy, ellipsometry, and water contact angle measurements. The thickness of the polydimethylsiloxane-block-poly(ethylene glycol) (PDMS-b-PEG) diblock copolymer brush could be controlled by the irradiation time. The responsive behavior of diblock copolymer brushes treated in different solvents was also discussed. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012