Polymer Brushes An Overview

Chemical Engineering Department, Petroleum Institute, Abu Dhabi, United Arab Emirates 

Surface properties of substrates are among the most important contributors to their applications, especially when the application involves the interaction of the surfaces with foreign media or entities. As an example, the surface properties are of tremendous importance when the chromatographic separations of proteins, polymers, or any mixture must be handled. There is always a requirement or desire to achieve extra functionalities on the surface by controlling the surface properties of the substrates, which can be used for one application or another or a combination of a few. The substrates can also be of any nature, e.g., flat, spherical, colloidal, etc. These functionalized surfaces represent a novel class of materials, which at the forefront of technology can lead to revolutionary changes in the conventional processes. 

Brzozowska et al. [18] reported on the stability of the polymer brushes formed by adsorption of ionomer complexes on hydrophilic and hydrophobic surfaces. The ionomer complexes or micelles consisted of oppositely charged polyelectrolyte blocks (poly(acrylic acid) and poly(N-methyl-2-vinyl pyri-dinium iodide)), and a neutral block (poly(vinyl alcohol)) or neutral grafts (poly(ethylene oxide)). The results showed that adsorbed micellar layers were relatively weakly attached to hydrophobic surfaces and much stronger 

It was observed that the adsorbed layers lowered the attraction between the surface and the hydrophilic probe. Friction between the coated surfaces and the colloidal probe also remained low, indicating that adsorbed micellar layers were mobile and had lubricating properties. 

Force curves measured between (A) silica (a) and polystyrene (b) substrates coated with C3M-PEO204/PAA139 and a silica probe at 10 mM NaCl, pH 7 (B) silica (a) and polysulfone (b) substrates coated with C3M-PVA445/P2MVPI228, and a silica probe at 10 mM NaCl, pH 7. Closed symbols correspond to approach and open to retraction. C3M corresponds to complex coacer-vate core micelles. (Reproduced from Brzozowska, A. M., et al.. Journal of Colloid and Interface Science, 353,380-91,2011. With permission from Elsevier.) 

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Surface-chemical gradients are mainly prepared via two systems self-assembled monolayers (SAMs) or polymer coatings, especially brush-like polymer coatings—Table 1 provides an overview of the different preparation methods for the generation of surface-chemical gradients and the applications for which they have been used. 

Abstract The current chapter gives a general overview on surface-initiated nitroxide-mediated polymerization (SI-NMP). More particularly, the developed strategies to perform an SI-NMP process, the various type of substrates including inorganic and organic supports, and the potential of SI-NMP to prepared advanced materials are discussed. Based on a selected number of literature examples it appears that SI-NMP is a versatile and powerful approach to introduce polymer brushes on surfaces and/or tune polymer surface properties. 

This chapter reviews recent work in the emerging field of partide brash-based nanocomposite materials. The aim is to equip the reader with the necessary backgrormd to effectivdy design partide brash materials for nanocomposite formulations with tailored properties and to provide an overview of recent experimental work on the effect of polymer graft architecture on the structure and properties of partide brash-based (quasi-one-component) nanocomposites. The chapter is structured into two parts In the first part the relevant theoretical and experimental backgrormd on the structure of partide brash systems is presented with the aim to establish the key structural parameters (and their relation to the molecular architecture of the partide brash) that determine the properties of partide brash-based materials. In the second part, recent experiments on partide brush-based nanocomposites will be reviewed. The effect of polymer graft modification on the properties of partide brash assemblies will be illustrated and discussed in the context of theoretical descriptions presented in the first part of... 

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