Thomas Vilmin

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In attempting to reduce the size of functional devices, the thickness of polymer films has reached values even smaller than the diameter of the unperturbed molecule. However, despite enormous efforts for more than a decade, our understanding of the origin of some puzzling properties of such thin films is still not satisfactory and several peculiar(More)
Adhesion at polydimethylsiloxane (PDMS)-acrylic adhesive interfaces is shown to be enhanced through micropatterning of the PDMS substrate. By varying the geometry of the patterns (groves and hexagonal arrays of pillars of micrometer sizes, obtained through soft lithography techniques) and comparing rigid and deformable substrates, the respective roles of(More)
We study the dewetting of thin polymer films deposited on slippery substrate. Recent experiments on these systems have revealed many unexpected features. We develop here a model that takes into account the rheological properties of polymer melts, focussing on two dewetting geometries (the receding of a straight edge, and the opening of a hole). We show that(More)
We study the crack-front fingering instability of an elastic adhesive tape that is peeled off a solid substrate. Our analysis is based on an energy approach using fracture mechanics and scaling laws and provides simple physical explanations for (i) the fact that the wavelength depends only on the thickness of the adhesive film and (ii) the threshold of the(More)
We study the adhesion between a cross-linked elastomer and a flat solid surface where polymer chains have been end-grafted. To understand the adhesive feature of such a system, one has to study both the origin of the grafted layer interdigitation with the network, and the endgrafted chains extraction out of the elastomer when it comes unstuck from the solid(More)
We study the friction between a flat solid surface where polymer chains have been end-grafted and a cross-linked elastomer at low sliding velocity. The contribution of isolated grafted chains’ penetration in the sliding elastomer has been early identified as a weakly velocity dependent pull-out force. Recent experiments have shown that the interactions(More)
We study the influence of lateral stress on the stability of thin viscoelastic films. The free surface of a deposited film under stress is shown to undergo an instability initiated by an anisotropic diffusion of the polymer molecules. This instability ultimately results in the formation of holes provided that the initial surface fluctuations are larger than(More)
The study of the dewetting of very thin polymer films has recently revealed many unexpected features (e.g. unusual rim morphologies and front velocities) which have been the focus of several theoretical models. Surprisingly, the most striking feature of all, that is a decrease of the rim width with time, have not yet been explained. In the present letter,(More)