Cationic bulk polymerization of mesogenic vinyl ethers induced by thermal decomposition of sulfonium salts

Molecular Engineering of Side Chain Liquid Crystalline Polymers

“…30 51 Scheme 2 provides some representative examples of mesogenic vinyl ethers which could be polymerized by a living mechanism with our preferred initiating system (i.e., CF 3 SO 3 H, (CH 3 ) 2 S, CH 2 C2, 0 OC). 52 As we can observe from Scheme 2, vinyl ethers containing nucleophilic groups such as methoxybiphenyl, 4 4 electronwithdrawing groups such as cyanobiphenyl, 3 0 3 5 ,4 4 .4 5 nitrobiphenyl and cyanophenylbenzoate, 44 double bonds like in 4-alkoxy-a-methylstilbene, 46 double bonds and cyano groups like in 4-cyano-4'-a-cyanostilbene, 34 aliphatic aromatic esters, 36 acidic protons and perfluorinated groups, 44 . 47 oligooxyethylene and aromatic ester groups 4 9 crown…”

“…54 , 55 When the polymerization is performed in liquid crystalline phase with aligned films of liquid crystalline monomers, perfectly alligned single crystal liquid crystalline polymer films are obtained. 54 , 55 In the following two subchapters we will discuss two topics. The first one refers to the influence of molecular weight on the phase transitions of poly(o-[(4-cyano-4'-biphenylyl)oxy]alkyl vinyl ether)s with alkyl groups containing from four to eleven methylene units.…”

“…In addition, cationic polymerization of any of these monomers can be performed in melt phase either in liquid crystalline phase or in isotropic phase by using thermal 53 , or photo cationic initiators. 54 , 55 When the polymerization is performed in liquid crystalline phase with aligned films of liquid crystalline monomers, perfectly alligned single crystal liquid crystalline polymer films are obtained. 54 , 55 In the following two subchapters we will discuss two topics.…”

Cationic bulk polymerization of vinyl ethers in the liquid crystalline phase

“…21,22) are used, the polymerization has been shown to tolerate a large number of functional groups (Refs. 14, 15,[18][19][20]. In addition, the flexible poly(vinyl ether) chain represents a suitable backbone for LC polymers since its flexibility tolerates its fast distortion at various phase transitions.…”

“…It has also been shown that vinyl ethers can be polymerized by a living cationic mechanism, giving well-defined polymers with narrow molecular mass distributions and tailored molecular masses (Refs. [8][9][10][11][12][13][14][15][16][17][18][19][20]. If initiating systems based on ethylaluminumdichloride and dimethylsulfide or triflic acid and dimethylsulfide (Refs.…”