title: Tris-cis-tris-trans-dodeca[organo(dimethylorganosiloxy)]cyclododecasiloxanes {RSi(O)[OSiMe2R']}12. Self-ordering features.
abstract: The molecular order and thermotropic transitions of tris-cis-tris-trans-dodeca- [organo(dimethylorganosiloxy)]cyclododecasiloxanes {RSi(O)[OSiMe(2)R']}(12) (R = Ph, R' = Me, CH(2)Cl, Vi; R = Me, Et, Vi, R' = Me) have been investigated using differential scanning calorimetry, thermogravimetric analysis, and X-ray scattering. The cyclododecasiloxanes with phenyl side groups (R = Ph) can form mesomorphic structures within a very wide temperature range. Compounds with R = Me and Vi are liquids and exhibit microphase separation above their glass transition temperature because of the different nature and structure of the organic R and trimethylsiloxy OSiMe(3) side groups. When the side group R = Et, a mesomorphic structure is formed in a substantially more narrow temperature region than that for cycles containing phenyl groups. Thus, the type of side group R in organocyclododecasiloxanes determines their ability for self-ordering into mesomorphic structures and the thermal stability of the mesomorphic state.
authors.affiliation: Department of Physics, Moscow State Pedagogical University, Malaya Pirogovskaya St. 1, Moscow 119882, Russia.
authors.forename: Elena V
authors.initials: EV
authors.lastname: Matukhina
authors.forename: Yulia A
authors.initials: YA
authors.lastname: Molodtsova
authors.forename: Yulia A
authors.initials: YA
authors.lastname: Pozdnyakova
authors.forename: Mikhail I
authors.initials: MI
authors.lastname: Buzin
authors.forename: Viktor G
authors.initials: VG
authors.lastname: Vasil'ev
authors.forename: Dimitris E
authors.initials: DE
authors.lastname: Katsoulis
authors.forename: Olga I
authors.initials: OI
authors.lastname: Shchegolikhina