This paper summarizes work done on LC-materials, which owe their properties to competing interactions and a structuring on different length scales. These are smectic layer structures and preferably colloids from LC-polymers. Mikro- and nm sized LC-colloids of a narrow size distribution [1,2] can be prepared by a controlled precipitation polymerization or miniemulsion techniques. Here the competition between the shape of the colloids and the orientation of the LC-phase, as well as the possibility to manipulate them in external fields are of interest. Mikrometer sized LC-colloids. Colloids from LC-polyacrylates can be prepared in a one step reaction by a controlled precipitation reaction [1] called “dispersion polymerization” [3]. In this way LC-colloids with different smectic and nematic phases and a diameter in the ?m range have been prepared [1]. Their size distribution is rather narrow. These materials are of interest for optical tracer experiments as they can be catched and rotated in optical tweezers. These experiments can be used to determine e.g. the rotational viscosity of colloids. In addition the interactions between the anisotropic colloids are of interest. Nanometer sized LC-colloids. Smaller colloids, whose size is in the range of 100 nm can be made by miniemulsion techniques [2]. This method allows also the use of ferroelectric LC-copolysiloxanes. In these copolymers a microphase separation occurs between mesogenic groups and polysiloxane chains. This microphase separation is presumably the reason for the “de Vries type” smectic A phase observed [4]. Independent of this microphase separation a photo-induced shift of the phase transition temperatures by up to 14 °C can be reversibly induced by the isomerization of azobenzene moieties [5]. Transmission electron microscopy on such colloids in the frozen solvent (water) show their smectic layer structure due to the contrast between the silicon backbone and the hydrocarbon mesogens. In these smaller colloids the interplay of the orientational tendencies of smectic layers and the shape of the colloids can be studied, leading either to colloids with straight layers or to colloids with an onion-like layer structure [2].

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