Complexation between pyridines and carboxylic acids is driven by hydrogen bonding. This simple, single hydrogen bond is shown to be capable of serving concomitantly as both the agent of liquid crystallinity and as the coupling bond generating an extended linear chain structure. Three such complexes made from an aromatic diacid and three structurally different bis pyridyls were prepared. In each case the association complex self‐assembles into an organized liquid crystalline phase. Discussion of this complexation as a step‐growth polymerization process is presented along with an examination of the suitability of various methods for characterizing these materials.

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Ethyl a-(chloromethyl)acrylate was converted to a variety of new ether derivatives using triethylamine-catalyzed reaction with commercially available fluoroalkyl alcohols. Rapid, high-conversion polymerization of neat monomers occurred with 2,2'-azobis(isobutyronitrile) at 50-70 °C. Monomers and polymers were characterized by FTIR, both solutionand solid-state 13C NMR spectroscopy, differential scanning calorimetry, optical microscopy, viscosity, gel permeation chromatography (GPC), and X-ray analysis. Weight-average molecular weights (Mw) estimated by GPC ranged from 3.02 X106 to 7.59 X105. Additionally, tert-butyl a-(hydroxymethyl)acrylate (tBHMA) was converted to a-(chloromethyl)acryloyl chloride in one step. This reactive intermediate allows incorporation of identical ester and ether moieties (e.g., trifluoroethyl) or mixed ester-ether units consisting of, for example, perfluoroalkyl ether units with either hydrophilic esters (based on oligomers of ethylene oxide) or lipophilic esters such as longer alkyl and tert-butyl derivatives. Polymers containing longer alkyl and tert-butyl ester units had Afw(GPC) values ranging from 3.98 X 104 to 6.0 X 104. Monomers with a semifluorinated ether group containing ten CF2 units were found to form highly ordered smectic B-like mesophases, which were confirmed by optical microscopy and X-ray analysis. Especially interesting was the persistence of the order in polymers obtained by polymerization in the mesophase. For example, the ethyl ester polymer showed much sharper X-ray peaks when obtained by in situ polymerization (in the monomer liquid crystal phase) than polymer reprecipitated from solution. Analogous diacrylates were synthesized by reacting the chloromethyl acid chloride with various diols followed by ether formation with fluoroalcohols. Most interesting was the ability of the mono-and diacrylate compounds incorporating ethylene oxide ester units to form liquid crystalline phases similar to that of the ethyl ester monomer. All the polymers containing ten CF2 units in the side chain exhibited a single first-order transition by DSC (48-58 °C) which corresponds to melting of the side chain crystals independent from the main chain behavior.

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