Coating of surfaces with stabilized reactive micelles from poly(ethylene glycol)-poly(DL-lactic acid) block copolymer

Reactive micelle was prepared from an end-derivatized block copolymer, acetal-poly(ethylene glycol)poly(DL-lactic acid)-methacrylate (PEG-PLA). The block copolymer of PEG-PLA formed a micelle with a diameter of approximately 30 nm determined from dynamic Light scattering. The glass and Si wafer surfaces coated with 3-aminopropyltriethoxysilane and poly(dimethylsiloxane) (PDMS) treated with N(2) + H(2) plasma were coated with the micelle, and the coating was characterized by zeta-potential profile, dynamic contact angle, and atomic force microscopy. The micelle with polymerized core maintained its structure on the surface while the nonpolymerized micelle was disrupted upon attachment. Compared with PEG coatings, micelle coating has higher advancing angle, and larger hysteresis, resulting from the conformational difference of PEG between the homopolymer and the micelle, and the micelle-induced surface topography. The zeta-potential of glass surface coated with the micelle is similar to that with PEG despite the larger dimension of the micelle. However, plasma-treated PDMS showed appreciable magnitude of zeta-potential even PEG was coated, while micelle-coated PDMS showed similar zeta-potential to the glass coated with the micelle. The coatings with PEG-PLA micelles can be applied to the design of nonfouling surfaces and medical implants.