Graft Copolymerization of Glass Fiber and Its Application

Surface modifications by polymers for biomolecule conjugation

Polymeric coatings, usually referred as tridimensional chemistries, provide homogenous surface derivatization methods presenting a high reactive group concentration and resulting in an increased binding capacity of targets. Furthermore, they act as linkers distributing the bound probe also in the axial position, thus causing a faster reaction with the target involved in biomolecular recognition and can be engineered to custom tailor their properties for specific applications. Most approaches which aim at attaching polymers to a surface use a system where the polymer carries an "anchor" group either as an end group or in a side chain. This anchor group can reacts with appropriate sites at the substrate surface, thus yielding surface-attached monolayers of polymer molecules (termed "grafting to"). Another technique is to carry out a polymerization reaction in the presence of a substrate onto which monomers had been attached leading to the so called "grafting from" approach. In this chapter, protocols to functionalize glass and silicon surfaces by "grafting to" as well as by "grafting-from" approach are shown using copolymers made of N,N-dimethylacrylamide (DMA) or Glycidyl methacrylate (GMA) as the polymer backbone, N-acryloyloxysuccinimide (NAS) as reactive group, and 3-(trimethoxysilyl)propyl methacrylate (MAPS) or 3-mercaptopropyl trimethoxy silane (MPS) as anchoring groups.

RAFT "grafting-through" approach to surface-anchored polymers: Electrodeposition of an electroactive methacrylate monomer

The synthesis of homopolymer and diblock copolymers on surfaces was demonstrated using electrodeposition of a methacrylate-functionalized carbazole dendron and subsequent reversible addition-fragmentation chain transfer (RAFT) "grafting-through" polymerization. First, the anodically electroactive carbazole dendron with methacrylate moiety (G1CzMA) was electrodeposited over a conducting surface (i.e. gold or indium tin oxide (ITO)) using cyclic voltammetry (CV). The electrodeposition process formed a crosslinked layer of carbazole units bearing exposed methacrylate moieties. This film was then used as the surface for RAFT polymerization process of methyl methacrylate (MMA), styrene (S), and tert-butyl acrylate (TBA) in the presence of a free RAFT agent and a free radical initiator, resulting in grafted polymer chains. The molecular weights and the polydispersity indices (PDI) of the sacrificial polymers were determined by gel permeation chromatography (GPC). The stages of surface modification were investigated using X-ray photoelectron spectroscopy (XPS), ellipsometry, and atomic force microscopy (AFM) to confirm the surface composition, thickness, and film morphology, respectively. UV-Vis spectroscopy also confirmed the formation of an electro-optically active crosslinked carbazole film with a [Formula: see text] - [Formula: see text] absorption band from 450-650nm. Static water contact angle measurements confirmed the changes in surface energy of the ultrathin films with each modification step. The controlled polymer growth from the conducting polymer-modified surface suggests the viability of combining electrodeposition and grafting-through approach to form functional polymer ultrathin films.