Enhanced Stability of Low Fouling Zwitterionic Polymer Brushes in Seawater with Diblock Architecture

Abstract

The successful implementation of zwitterionic polymeric brushes as antifouling materials for marine applications is conditioned by the stability of the polymer chain and the brush-anchoring segment in seawater. Here we demonstrate that robust, antifouling, hydrophilic polysulfobetaine-based brushes with diblock architecture can be fabricated by atom-transfer radical polymerization (ATRP) using initiator-modified surfaces. Sequential living-type polymerization of hydrophobic styrene or methyl methacrylate and commercially available hydrophilic sulfobetaine methacrylamide (SBMAm) monomer is employed. Stability enhancement is accomplished by protecting the siloxane anchoring bond of brushes on the substrate, grafted from silicon oxide surfaces. The degradation of unprotected PSBMAm brushes is clearly evident after a 3 month immersion challenge in sterilized artificial seawater. Ellipsometry and atomic force microscopy (AFM) measurements are used to follow changes in coating thickness and surface morphology. Comparative stability results indicate that surface-tethered poly(methyl methacrylate) and polystyrene hydrophobic blocks substantially improve the stability of zwitterionic brushes in an artificial marine environment. In addition, differences between the hydration of zwitterionic brushes in fresh and salt water are discussed to provide a better understanding of hydration and degradation processes with the benefit of improved design of polyzwitterionic coatings.

Poly(ethylene oxide)-based block copolymers with very high molecular weights for biomimetic calcium phosphate mineralization

“…Interestingly, positively charged, [75][76][77] properties that should also be interesting for dental applications. Additionally, these polymers are able to interact with solids.…”

Deposition of zwitterionic polymer brushes in a dense gas medium

“…The resulting mixture was stirred until homogenization and then was transferred by cannula into a customized reactor containing the CMPS-modified silicon substrates. The reactor was placed in an oil bath at 25°C and the reaction was continued for 12 h. Then, the substrates were removed from the reactor and rinsed several times with warm water and methanol, and finally rinsed with abundant water and dried under a stream of argon [6,7].…”

“…Zwitterionic species such as sulfobetaine methacrylate (SBMA) and sulfobetainemethacrylamide (SBMAm) grafted polymer brushes have shown excellent antifouling properties [1,[6][7][8][9][10]. The presence of zwitterions in the polymer led to the overall electrical neutrality and a dehydrated state [11].…”

“…Solution (liquid) based ATRP reactions tends to immobilize the catalyst in the polymer brush after the reaction has been completed [6]. Currently, copper coatings are widely used to prevent antifouling.…”

Boundary lubrication of stainless steel and CoCrMo in aqueous systems

“…It is shown that the low friction is attributed to the hydration lubrication mechanism arising from rubbing of the highly hydrated phosphocholine-head group layers exposed at the outer surface of each liposome, and provides support for the conjecture that phospholipids may play a significant role in biological lubrication [104]. Quintana et al reported some low fouling zwitterionic polymer brushes with diblock architecture which can enhance the stability in seawater [105]. Hydrophilic polymer brushes can also improve the wettability and antifouling behaviour of the surfaces [106].…”