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Polymer brushes: "A new step for surface engineering"Olivier, Aurore 21 September 2010 (has links)
Polymer brushes represent a relatively new class of materials and are referred to an assembly of polymer chains tethered by one of their extremities to a surface by a chemical bond. Different techniques to produce polymer brushes exist but our privileged choice was about the ¡§grafting from¡¨ method due to the better control over the types of grafted polymer, the surface-grafting density, and the chain-lengths. In our project, we focused on polymerizations from self-assembled monolayers of thiol chemisorbed on gold surface, bearing end-group functions as anchoring sites. The main objective of this work is to develop multifunctional polymeric surfaces composed by micro-domains of diverse compounds, which contain opposite features. Poly(ƓÕ-caprolactone) and poly(L,L-lactide)-based brushes both known for their high degree of crystallinity and hydrophobicity, and poly(dimethylamino ethyl methacrylate) (PDMAEMA)-based brushes for their hydrophilicity and external stimuli responsive characteristics were investigated. Moreover, the design of these advanced materials can be achieved with patterning technique such as micro-contact printing, leading to a spatial confinement of the polymer brushes.
In order to reach our objective, the thesis was decomposed in different parts. First, the preparation of homogeneous and heterogeneous monolayers derived from thiols on gold surface will be investigated. Secondly, the ¡§grafting from¡¨ synthesis of homo-polymers from thiol end group will be carried out. This part required the development of synthesis conditions for both types of homopolymer brushes. Subsequently, these parameters were applied to the creation of a binary system by the growth of two different macromolecular chains on the same substrate. Finally, upon the ¡§smart¡¨ behavior of PDMAEMA, the potential of the polymer as chemical sensor was evaluated with single walled and multi walled-carbon nanotubes (SW- and MW-CNTs) as interesting conductive (nano)fillers.
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