TWISTING TRANSITION IN A FIBER COMPOSED OF CHIRAL SMECTIC-C LIQUID-CRYSTAL POLYMER

We consider a cylindrical fiber composed of main-chain liquid crystal polymer in the chiral smectic-C phase. Due to steric constraints on th e liquid crystal polymer, the smectic layers orient perpendicular to t he fiber axis, the liquid crystal director lies flat against the fiber wall, and a line disclination appears along the fiber axis. Using a L andau-de Gennes expression for the elastic free energy, we show that t he fiber may undergo a transition from a cylinder to a helix. transiti on is favored by large chirality, large fiber radius, and low surface tension, but is probably not experimentally accessible. However, a,rel ated transition involving only the disclination should be observable.