Microstructured poly(2-oxazoline) bottle-brush brushes on nanocrystalline diamond

Abstract

We report on the preparation of microstructured poly(2-oxazoline) bottle-brush brushes (BBBs) on nanocrystalline diamond (NCD). Structuring of NCD was performed by photolithography and plasma treatment to result in a patterned NCD surface with oxidized and hydrogenated areas. Self-initiated photografting and photopolymerization (SIPGP) of 2-isopropenyl-2-oxazoline (IPOx) resulted in selective grafting of poly(2-isopropenyl-2-oxazoline) (PIPOx) polymer brushes only at the oxidized NCD areas. Structured PIPOx brushes were converted by methyl triflate into the polyelectrolyte brush macroinitiator for the living cationic ring-opening polymerization (LCROP) of 2-oxazolines. The LCROP was performed with 2-ethyl-2-oxazoline (EtOx) as well as 2-(carbazolyl)ethyl-2-oxazoline (CarbOx) as monomers, resulting in structured bottle-brush brushes (BBB) with different pendant side chains and functionalities. FT-IR spectroscopy, fluorescence microscopy, and AFM measurements indicated a high side chain grafting density as well as quantitative and selective reactions. Poly(2-oxazoline) BBBs containing hole conducting carbazole moieties on NCD as electrode material may open the way to advanced amperometric biosensing systems.

Tailored Poly(2‐oxazoline) Polymer Brushes to Control Protein Adsorption and Cell Adhesion

“…This concept could be readily used to prepare grafted BBBs of different compositions and on various surfaces. Here, the BBB stem was grafted by means of self‐initiated photografting and photopolymerization (SIPGP) directly on glassy carbon63 or diamond64, 65 as both substrates are suitable for biosensing. Moreover, the BBB architecture and the POx chemistry allows for multiple functionalizations at the side chain pendant and terminal positions.…”

“…Moreover, the BBB architecture and the POx chemistry allows for multiple functionalizations at the side chain pendant and terminal positions. Hole transporting groups (carbazole)64 as well as large model proteins (e.g., GFP)65 have been introduced and demonstrating the versatility of the system for biosensing purposes. However, as glassy carbon and especially diamond shows already exceptional biocompatibility66 the protein repellant properties of the POx‐BBB coatings were not addressed.…”

Design Strategies for Functionalized Poly(2-oxazoline)s and Derived Materials

“…The chemical composition and architecture of these types of brushes was correlated with the adsorption and adhesion of proteins. Garrido, Jordan et al prepared structured poly(2-oxazoline) bottle-brush brushes also on nanocrystalline diamond (NCD) surfaces, where covalent attachment during photografting was observed to the oxidized NCD areas selectively [99]. After the reaction with methyl triflate, the thus-generated macroinitiators started by the CROP of EtOx or CarbOx, bottle-brush brushes containing hole-conducting moieties such as carbazole units were described as potential amperometric biosensing systems.…”

A strong cationic Brønsted acid, [H(OEt2)2][Al{OC(CF3)3}4], as an efficient initiator for the cationic ring-opening polymerization of 2-alkyl-2-oxazolines

“…[50][51][52] Fig. 3 shows a comparison of the FT-IR spectra for PEtOx 60 (blue line), PtButOx 60 (red line), and PEtOx 30 -co-PtButOx 30 (cyan line).…”