Surface-Initiated ARGET ATRP of Antifouling Zwitterionic Brushes Using Versatile and Uniform Initiator Film

Abstract

In this study, we developed a uniform initiator layer that can be formed on various surfaces, and formed site-selectively, for the subsequent antifouling polymer brush formation. Initially, metal–organic films composed of tannic acid (TA) and FeIII ions (TA-FeIII) were formed on various surfaces, followed by functionalization with an aryl azide-based initiator (ABI) under photoreaction. In particular, combination with a photolithographic technique enabled the presentation of initiators only on the intended region within a single-surface platform. A resultant initiator film (TF-ABI) was formed under mild reaction conditions and meets the uniformity and transparency requirements concurrently. Subsequently, we showed that TF-ABI can be further utilized to form a polymer brush by proceeding with surface-initiated polymerization using a zwitterionic monomer, namely, sulfobetaine acrylamide (SBAA). Instead of applying a classical, yet air-sensitive atom transfer radical polymerization (ATRP) technique, we utilized an activator regenerated by electron transfer (ARGET) ATRP under air conditions without a cumbersome deoxygenation step. Overall, our initiator layer allowed the antifouling poly­(SBAA) brush to be used on various surfaces, and enabled their pattern generation.

Synthesis and formulation of self‐immolative PEG‐aryl azide block copolymers and click‐to‐release reactivity with trans‐cyclooctene

“…47 As a result of our inability to control polymerization using RAFT, synthesis of 2 was attempted using ATRP. Others have recently demonstrated the controlled synthesis of block copolymers with an aryl azide backbone or aryl azide initiator using ATRP methodology, 64,65 but to the best of our knowledge there have been no reports on the synthesis of self-immolative aryl azides and use in stimuli-responsive polymer backbones. For ATRP synthesis of 2, polyethylene glycol (PEG) macroinitiator (mPEG-Br) 6 was first synthesized using a literature procedure, 66 and reacted with methacrylate 4 under various ATRP conditions ( Table 2, Entries 1-6).…”

Synthesis of Polymer Brushes Via SI‐PET‐RAFT for Photodynamic Inactivation of Bacteria

“…While brushed surfaces of hydrophilic and zwitterionic chemical moieties have exhibited excellent antifouling capabilities, their lack of bactericidal properties cannot prevent long term colonization from opportunistic pathogens. [ 7 ] On the other hand, while cationic polymer brushes are known to display efficient killing activity, they are inherently limited by the loss of antimicrobial activity, and selectivity against different strains of bacteria. [ 8 ] Several studies have focused on the preparation of polymer brushes with the aim of combining antifouling and killing capabilities.…”

Formation of Various Polymeric Films via Surface‐Initiated ARGET ATRP on Silicon Substrates

“…In ARGET ATRP process, an excess amount of a reducing agent is used that can continuously regenerate active Cu(I) species from dormant Cu(II) species, even under atmospheric conditions. 19 Because of this regenerative catalytic cycle, ARGET ATRP needs no deoxygenating steps for the reaction solutions and it can be proceeded with a very low concentration of a Cu catalyst (at the level of several ppm) under ambient conditions. Along the same line with grafting-from approach, surface-initiated ARGET ATRP (SI-ARGET ATRP) has been successfully applied to a variety of applications including the preparation of low fouling surfaces, 20,21 development of the universal polymer grafting method to fabricate blood compatible surfaces, 22 and the preparation of biocompatible graphene nanosheets.…”

“…These drawbacks have been recently mitigated by the introduction of activators regenerated by electron transfer ATRP (ARGET ATRP). In ARGET ATRP process, an excess amount of a reducing agent is used that can continuously regenerate active Cu(I) species from dormant Cu(II) species, even under atmospheric conditions 19 . Because of this regenerative catalytic cycle, ARGET ATRP needs no deoxygenating steps for the reaction solutions and it can be proceeded with a very low concentration of a Cu catalyst (at the level of several ppm) under ambient conditions.…”