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Article Dans Une Revue Langmuir Année : 2010

Density Effects on Collapse, Compression, and Adhesion of Thermoresponsive Polymer Brushes

Résumé

We probe, using the surface forces apparatus, the thermal response of poly(N-isopropylacrylamide) (PNIPAM) brushes of various grafting densities, grown from plasma-activated mica by means of surface-initiated polymerization. We thus show that dense thermoresponsive brushes collapse gradually as temperature is increased and that grafting density greatly affects their ability to swell: the swelling ratio of the brushes, which characterizes the thickness variation between the swollen and the collapsed state, is found to decrease from similar to 7 to similar to 3 as the number of grafted chains per unit area increases. Such a result, obtained with an unprecedented resolution in grafting density, provides qualitative support to calculations by Mendez et al. [Macromolecules 2005, 38, 174]. We further show that, in contrast to swelling, adhesion between two PNIPAM brushes appears to be rather insensitive to their molecular structure.

Dates et versions

hal-01239417 , version 1 (07-12-2015)

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Citer

Ibrahim B. Malham, Lionel Bureau. Density Effects on Collapse, Compression, and Adhesion of Thermoresponsive Polymer Brushes. Langmuir, 2010, 26 (7), pp.4762-4768. ⟨10.1021/la9035387⟩. ⟨hal-01239417⟩
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