Temperature-Electricity-pH-Responsive LCEs

In the nematic phase, this ratio is larger than unity (R /R 1.3) (Warner and Terentjev, 1996), but after a nematic-isotropic phase transition, this ratio approaches unity as a result of the formation of a random coil of polymer chains, which makes the polymer material contract along the director axis of LCEs. In the smectic A phase, the ratio R /R is in general smaller than unity because the polymer chains are likely to exist between the smectic layers (Cotton and Hardouin, 1997). 

There have been a number of efforts to develop artificial musclelike materials (Buguin et al., 2006 Mol et al., 2005 Saikrasun et al., 2005 Stenull and Lubensky, 2005 Li et al., 2004 Naciri et al., 2003 Clarke et al., 2001 Mao et al., 2001 Thomsen et al., 2001). LCE films with a splayed or twisted molecular alignment 

Skeletal muscles are anisotropic, that is, they exhibit contraction and elongation along the fiber axis. Naciri et al. (2003) described a method of preparing LC fibers from a side-chain LC terpolymer containing two side-chain mesogens 

Another useful property of LCEs is that their shape changes by applied electric fields, electromechanical responses, owing to reorientation effects induced by electric field. Zentel first found tiny changes of LCEs swollen in LMWLCs under large fields in 1986 (Zentel, 1986). Subsequently, Barnes et al. (1989) observed 20% contraction of polydomain elastomers swollen in an isotropic LMWLC. Kishi et al. 

Photochemical Phase Transitions of LCs. Cooperative motion of molecules in LC phases may be most advantageous in changing the molecular alignment by external stimuli. If a small portion of LC molecules change their 

---