Self-assembled liquid-crystalline gels designed from the bottom up.
Liquid crystals are often combined with polymers to influence the liquid crystals' orientation and mechanical properties, but at the expense of reorientation speed or uniformity of alignment. We introduce a new method to create self-assembled nematic liquid-crystal gels using an ABA triblock copolymer with a side-group liquid-crystalline midblock and liquid-crystal-phobic endblocks. In contrast to in situ polymerized networks, these physical gels are homogeneous systems with a solubilized polymer network giving them exceptional optical uniformity and well-defined crosslink density. Furthermore, the unusually high-molecular-weight polymers used allow gels to form at lower concentrations than previously accessible. This enables these gels to be aligned by surface anchoring, shear, or magnetic fields. The high content of small-molecule liquid crystal (>/=95%) allows access to a regime of fast reorientation dynamics.
California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA.
Michael D
MD
Kempe
Neal R
NR
Scruggs
Rafael
R
Verduzco
Jyotsana
J
Lal
Julia A
JA
Kornfield
D001713:Biphenyl Compounds / Q000737:chemistry; D005782:Gels / Q000138:chemical synthesis*; D009570:Nitriles / Q000737:chemistry; D011108:Polymers / Q000138:chemical synthesis*
D001713:Biphenyl Compounds; D005782:Gels; D009570:Nitriles; D011108:Polymers; C422409:liquid crystal polymer; C433919:4-cyano-4'-pentylbiphenyl