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The synthesis of side‐chain liquid‐crystalline oligocyclosiloxanes containing methyleneoxymethylene spacers, two different mesogenic cores (including biphenyl phenyl carboxylate or biphenyl fluorophenyl carboxylate groups) and chiral tails is presented. Differential scanning calorimetry, optical polarizing microscopy and X‐ray diffraction measurements reveal liquid‐crystalline properties for all of the synthesized monomers and oligomers. All cyclic oligosiloxanes exhibit enantiotropic smectic A and chiral smectic C phases. The mesogenic properties of the cyclic oligomers and side‐chain liquid‐crystalline precursor are discussed. Copyright © 2005 Society of Chemical Industry

The cationic emulsion polymerization of octamethylcyclotetrasiloxane (D4) in mixtures with methyltriethoxysilane (MTES) and vinyltriethoxysilane (VTES) was studied by FTIR ATR, GC, the development of a toluene insoluble fraction of the polymer and a gravimetric analysis. The polymerization of D4 alone was also conducted for comparison and, additionally, the development of molecular weight of polydimethylsiloxane (PDMS) obtained in that process was studied by GPC. Dodecylbenzenesulphonic acid (DBSA) was used as a surfactant and catalyst. The process was carried out in a “starved feed” mode by adding dropwise the monomer mixture to the aqueous solution of DBSA. FTIR ATR spectra were recorded by the sensor placed in the probe tip of a ReactIR 15TM apparatus. It was found that the silicone polymer formation proceeded faster when D4 was polymerized in the mixture with alkoxysilanes, especially in the beginning of the process, and that already at the beginning of the process, the partly crosslinked polymer was formed. The induction period of ca. 30 min was observed and the concentration of cyclic siloxanes (D4 and decamethylcyclopentasiloxane—D5) remained at a very low level in the course of the reaction and only traces were detected in the final product. The particle size development in the course of the reaction was also studied and it was found that the particle size distribution was bimodal and was broadening as the reaction proceeded, though this phenomenon was less distinct when D4 was polymerized in the mixtures with alkoxysilanes. The structure of the reaction product was confirmed by 29Si NMR.

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