This contribution presents a new strategy to grow nonfouling poly (poly(ethylene glycol) methacrylate) (PPEGMA) brushes from polydimethylsiloxane (PDMS) substrates. The strategy presented here is based on the use of a sequence of vapor deposition/hydrolysis cycles to generate a surface-confined atom transfer radical polymerization (ATRP)-initiator functionalized interpenetrating polymer network (IPN) layer. In contrast to most other approaches that have been developed to graft thin polymer layers from PDMS substrates, this technique obviates the need for UV/ozone pretreatment of the PDMS substrate. it is shown that the surface-confined ATRP-initiator functionalized IPN layer can be used to grow PPEGMA brushes in a controlled fashion and that the resulting PPEGMA coating significantly reduces nonspecific protein adsorption as compared to unmodified PDMS substrates.