Side-chain liquid-crystalline copolymers (SCLCPs) were synthesized from the alternating copolymerization of maleic anhydride with mesogenic 1-olefins. These SCLCPs showed high glass transition temperatures and highly ordered smectic mesophases. The mesophase width increased with spacer length. The terminal alkyl group length determined the degree of order in the hexatic mesophase that was present just above the glass transition temperature. A terminal methoxy group induced a hexatic smectic B mesophase, intermediate terminal alkyl groups induced a smectic E mesophase, and long terminal alkyl groups induced a crystal smectic B mesophase. If the spacer was shorter than the terminal alkyl group, an interdigitated smectic A mesophase was found in which the terminal alkyl groups overlap. A strong correlation was found between the glass transition temperature and the temperature at which the hexagonal or orthorhombic ordered mesophase disappears. Introduction of an ester linkage between the spacer and biphenyl mesogen or replacing the terminal alkoxy group by a cyano terminal group induced a lowering of transition temperatures and a lower degree of order in the mesophase.

Spin-coated side-chain liquid-crystalline polymer films, based on alternating copolymers of maleic anhydride and α-olefins carrying terminal mesogenic methoxybiphenylyloxy groups, on silicon wafers show lamellar ordering upon annealing above the glass transition temperature. In the surface topography (atomic force microscopy measurements), structures are visible with a height corresponding to a bilayer. Also within the film, the side chains are ordered perpendicularly to the surface as measured by X-ray reflectometry. There are indications that directly at the substrate surface the side chains are aligned parallel to the surface. By the two complementary techniques, a rather complete picture is obtained. Even though the films are very thin (nanometer-scale thickness), the structure has a high degree of perfection and the bilayer spacing is the same as measured for bulk polymer.

The synthesis and characterization of liquid-crystalline polymers with possible good adhesive properties is reported. These polymers are prepared by alternating copolymerization of maleic anhydride and mesogenic alkenes. The spacer length m is varied (m = 2,3,4,6, 8 and 9) and methoxybiphenyl is used as the mesogenic group. The glass transition temperature decreases and the isotropization temperature increases with spacer length. Depending on the spacer length and temperature, Sg and SA,, mesophases can be observed. After annealing, spin-coated films of these polymers show very regular layered structures with a layer spacing similar to that in the bulk.

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Side-chain liquid-crystalline copolymers from maleic anhydride and 1-alkenes carrying biphenyl mesogens have been modified by reaction of the anhydride moieties with different mesogenic alcohols to give maleic acid monoesters. FTIR and 1H NMR showed high degrees of modification. Grafting methoxybiphenyl-containing alcohols having different spacer lengths onto methoxybiphenyl-containing polymers yielded polymers exhibiting smectic A mesophases with a variable degree of interdigitation. The glass transition temperature decreased with spacer length, whereas the isotropization temperature remained almost constant. Grafting azobenzene-containing alcohols onto methoxybiphenyl-containing copolymers yielded side-chain liquid-crystalline polymers exhibiting nematic mesophases. The effect of the 4‘-azobenzene terminal group on the temperature window of the mesophase was CN > OMe > F > H. Grafting a cyanostilbene-containing alcohol onto a methoxybiphenyl-containing copolymer resulted in a polymer that exhibited a smectic E mesophase with complete interdigitation of side chains. Introducing methoxybiphenyl mesogens into cyanobiphenyl-containing copolymers or vice versa resulted in polymers with smectic A mesophases. Furthermore, an increase in isotropization temperatures was observed in comparison with polymers carrying only one type of mesogen. This indicates specific favorable interactions between unlike mesogens.