Preparation and Characterization of a Polyelectrolyte Monolayer Covalently Attached to a Planar Solid Surface

Abstract

A novel concept for the synthesis of molecularly thin polyelectrolyte layers covalently attached to planar solid surfaces is introduced. The polymer monolayers are generated directly at the surface by using self-assembled monolayers of an azo initiator and radical chain polymerization in situ. This "grafting from" approach yields surface-bound polymer molecules with a high molecular weight and with high graft densities of the attached chains ("brush"-like state). As an example for the preparation of a positively charged polyelectrolyte "brush" at first a monolayer of poly(4-vinylpyridine) (PVP) was generated at the surface, which was subsequently quarternized to yield a poly[4-vinyl-N-n-butylpyridinium] bromide (BuPVP) monolayer. The thickness of this resulting cationic monolayer can be controlled in a wide range, starting from 2 nm to more than 1000 nm in the solvent-free state.

From Self-Assembled Monolayers to Coatings: Advances in the Synthesis and Nanobio Applications of Polymer Brushes

“…"Grafting-from" overcomes some of these limitations and has been used extensively with a variety of polymerization techniques such as ring-opening polymerization [13,14], ring-opening metathesis polymerization [15,16], anionic polymerization [17,18], cationic polymerization [19,20], conventional free radical polymerization [21,22], but perhaps the most widely used are the controlled radical polymerization (CRP) techniques (also called reversible-deactivation radical polymerization [23]), namely atom transfer radical polymerization (ATRP), nitroxide-mediated polymerization (NMP) and reversible addition-fragmentation chain-transfer (RAFT) polymerization [24][25][26][27]. Surface-initiated CRP has become the workhorse in the "grafting-from" literature because it is easy to polymerize a wide variety of monomers that contain an array of functional groups with a high degree of control [10].…”

In situ measurement of humidity induced changes in the refractive index and thickness of polyethylene glycol thin films

“…Growth of a stable PEG film onto gold is only possible by covalent attachment of the polymer molecules to the gold surface in concern. A chemical synthesis procedure called the grafting-from technique [5,6] is used to prepare relatively thick PEG layers for our optical experiments.…”

Nanoscale Conformation and Compressibility of Cartilage Aggrecan Using Microcontact Printing and Atomic Force Microscopy

“…This is not possible with more conventional techniques such as ellipsometry. 16 By measuring the height under different applied normal forces, additional information can be gathered about the nanomechanical properties of the polymer layer.…”