I. Les-cristaux-liquides-un-nouvel-État-thermodynamique-de-la-matière, .. Landau-de-gennes, and .. , 9 A. Définition d'un paramètre d'ordre 11 B. Modèle de, 14 E. Interaction avec un champ, p.15

I. Propriétés-de-surface-des-cristaux-liquides and .. , 23 A. Propriétés d'ancrage aux interfaces 23 B. Classification des ancrages 24 C. Approche macroscopique de l'énergie d'ancrage, ., p.30

I. Techniques-de-mesure-et-de-caractérisation, .. , A. Ellipsomètrie, and .. , 53 C. Mesure de l'orientation de l'axe facile, p.57

V. Orientation-d-'une-couche-d-'ancrage-azimutalement-dégénérée-par-un-réseau and .. , 109 A. Techniques de fabrication des réseaux, p.110

V. Annexes, .. Euler-lagrange, and .. , 129 A. Minimisation de l'énergie libre par la méthode 129 B. Matériaux d'ancrage étudiés, Biréfringence de forme, vol.137, p.141

D. Dépôt, Couche d'ancrage à base de polystyrène greffé Un premier essai de greffage de polystyrène (solution de 5% de polystyrène greffable dans du toluène) sur un des réseaux préparés à l'Institut d'Electronique Fondamentale montre que l'orientation due au réseau est bonne et parallèle au réseau. Cependant l'énergie de l'ancrage azimutal mesurée est très faible (la longueur d'extrapolation de l'ancrage azimutal est de l'ordre de 3 µ), et de ce fait insuffisante pour tenir le couple de torsion imposé par le volume dans un afficheur de type Binem®. On retrouve l'effet prédit par Faetti sur la dépendance de l'énergie de l'ancrage azimutal en fonction de l'énergie de l'ancrage zénithal [Faetti 1987]. On est cependant loin du compte en ce qui concerne l'ordre de grandeur de l'effet (Faetti prévoit une diminution d'environ 40% de l'énergie de l'ancrage azimutal, alors que nous constatons un effondrement de l'énergie d'ancrage azimutal)

. La-surface-est-fonctionnalisée-par-greffage-de-polystyrène, partir d'une solution de polystyrène greffable ? polystyrène non greffable -toluène de composition respectivement 0.1 -4.9 -95. C'est le taux de greffage qui nous a semblé le plus adapté pour pouvoir étudier les effets d'un réseau sur l'ancrage. En effet, l'ancrage sur surface ITO plane est planaire

. Hors-du-réseau, ancrage est planaire à température ambiante, avec un peu de mémoire. Si on chauffe la cellule, l'ancrage devient conique (cf. Figure VII-12 )

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