J. Phys. II France
Volume 6, Numéro 9, September 1996
Page(s) 1331 - 1340
DOI: 10.1051/jp2:1996134
J. Phys. II France 6 (1996) 1331-1340

Grafted Rods: A Tilting Phase Transition

F. Schmid1, D. Johannsmann2 and A. Halperin3

1  Institut für physik, Johannes-Gutenberg Universität, 55099 Mainz, Germay
2  ICSI, 15 rue Jean Starcky, BP 2488, 68057 Mulhouse Cedex, France
3  Max-Planck-Institut für Polymerforschung, Postfach 3148, 55021 Mainz, Germay

(Received 7 March 1996, revised 24 April 1996, accepted 10 May 1996)

A tilting phase transition is predicted for systems comprising rod like molecules which are irreversibly grafted to a flat surface, so that the non interacting rods are perpendicularly oriented. The transition is controlled by the grafting density  $\rho$. It occurs as $\rho$ increases as a result of the interplay between two energies. Tilt is favoured by the van der Waals attraction between the rods. It is opposed by the bending elasticity of the grafting functionality. The role of temperature is discussed, and the tilting mechanism is compared to other tilting transitions reported in the literature.

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