Surface-Initiated Atom Transfer Radical Polymerization of Oligo(ethylene glycol) Methyl Methacrylate from a Mixed Self-Assembled Monolayer on Gold

Abstract

This paper describes the in‐situ synthesis of an oligo(ethylene glycol)‐functionalized polymer brush in which the oligo(ethylene glycol) chains are presented as side‐chains from a methacrylate backbone that is anchored to the surface. These polymer “bottlebrushes” have been synthesized by surface‐initiated atom transfer radical polymerization (SI‐ATRP) of oligo(ethylene glycol) methyl methacrylate (OEGMA) from a mixed self‐assembled monolayer (SAM) of an ATRP initiator‐functionalized alkanethiol and a diluent, methyl‐terminated thiol. The systematic control of the ATRP initiator surface density afforded by the mixed SAM on gold and the polymerization time enables the polymer chain length and surface density to be independently controlled. Surface plasmon resonance (SPR) spectroscopy of fibronectin (Fn) adsorption on poly(OEGMA) grown from the surface of the mixed SAMs on gold shows that above a threshold solution molar ratio of the ATRP‐initiator thiol to methyl‐terminated thiol of 0.2, and a dry film thickness of ∼ 4 nm, Fn adsorption on the surface‐initiated poly(OEGMA) coatings was below the detection limit of SPR. The relatively low surface density of the ATRP initiator required to confer protein resistance to the surface suggests that SI‐ATRP may be a viable strategy to create protein resistant polymer brushes on real‐world materials.

A Facile Method for Permanent and Functional Surface Modification of Poly(dimethylsiloxane)

“…(2) Concentration gradient in "grafting to" strategy prevents the preparation of thick and dense films. 10 We reported herein a facile method for permanent and functional surface modification of PDMS based on a commercial material. First, a vinyl-terminated initiator (v-initiator, part C in Scheme 1) was mixed with the viscous base and curing agent of Sylgard 184, resulting in an initiator integrated PDMS (iPDMS).…”

Quartz crystal microbalance study of the kinetics of surface initiated polymerization

“…Previous studies have also demonstrated that polymer density could be controlled by varying surface density of initiator in SIP, yet the final density of the film was difficult to determine [43,49,50] .…”

“…Baker et al attributed this to the island formation of the initiator/undecanthiol mixed SAMs [50] . This phenomenon was also monomer dependent because it was found that film thickness stopped increasing as the initiator density increased for the monomer oligo(ethylene glycol) methacrylate (OEGMA) [43] . Thus, the value of IE may be determined by multiple factors and may vary throughout the course of polymerization.…”

“…The contact angle and the AFM measurements give surface energy and surface morphology (and other surface properties), respectively. Film thickness is another important physical index that characterizes surface coatings, which can be obtained by a number of methods such as AFM [41] and ellipsometry [42,43] . In the "grafting to" method, the tethered polymer chains are approximately treated the same as those free polymers in the grafting solution, which are typically characterized by parameters such as molecular weight (M n , the number averaged molecular weight and M w , the weight averaged one), polydispersity, and the degree of polymerization.…”

Fabrication of Two-Component, Brush-on-Brush Topographical Microstructures by Combination of Atom-Transfer Radical Polymerization with Polymer End-Functionalization and Photopatterning

“…For example, a number of brushes exhibit high resistance to biofouling. Poly(oligoethylene glycol methyl ether methacrylate) (POEGMEMA) bottle-brushes render a variety of surfaces highly resistant to the adsorption of proteins 8,9,10,11 . Other examples 3 of anti-fouling brushes include polybetaines 12,13 and poly(amino acid methacrylate) brushes 14,15,16 .…”