title: Preparation of Monodomain Liquid Crystal Elastomers and Liquid Crystal Elastomer Nanocomposites.
abstract: LCEs are shape-responsive materials with fully reversible shape change and potential applications in medicine, tissue engineering, artificial muscles, and as soft robots. Here, we demonstrate the preparation of shape-responsive liquid crystal elastomers (LCEs) and LCE nanocomposites along with characterization of their shape-responsiveness, mechanical properties, and microstructure. Two types of LCEs - polysiloxane-based and epoxy-based - are synthesized, aligned, and characterized. Polysiloxane-based LCEs are prepared through two crosslinking steps, the second under an applied load, resulting in monodomain LCEs. Polysiloxane LCE nanocomposites are prepared through the addition of conductive carbon black nanoparticles, both throughout the bulk of the LCE and to the LCE surface. Epoxy-based LCEs are prepared through a reversible esterification reaction. Epoxy-based LCEs are aligned through the application of a uniaxial load at elevated (160 °C) temperatures. Aligned LCEs and LCE nanocomposites are characterized with respect to reversible strain, mechanical stiffness, and liquid crystal ordering using a combination of imaging, two-dimensional X-ray diffraction measurements, differential scanning calorimetry, and dynamic mechanical analysis. LCEs and LCE nanocomposites can be stimulated with heat and/or electrical potential to controllably generate strains in cell culture media, and we demonstrate the application of LCEs as shape-responsive substrates for cell culture using a custom-made apparatus.
authors.affiliation: Chemical and Biomolecular Engineering, Rice University.
authors.forename: Hojin
authors.initials: H
authors.lastname: Kim
authors.affiliation: Chemical and Biomolecular Engineering, Rice University.
authors.forename: Bohan
authors.initials: B
authors.lastname: Zhu
authors.affiliation: Bioengineering, Rice University.
authors.forename: Huiying
authors.initials: H
authors.lastname: Chen
authors.affiliation: Bioengineering, Rice University.
authors.forename: Oluwatomiyin
authors.initials: O
authors.lastname: Adetiba
authors.affiliation: Chemical and Biomolecular Engineering, Rice University.
authors.forename: Aditya
authors.initials: A
authors.lastname: Agrawal
authors.affiliation: Materials Sciences and NanoEngineering, Rice University.
authors.forename: Pulickel
authors.initials: P
authors.lastname: Ajayan
authors.affiliation: Bioengineering, Rice University; Congenital Heart Surgery Services, Texas Children's Hospital.
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Jacot
authors.affiliation: Chemical and Biomolecular Engineering, Rice University; Materials Sciences and NanoEngineering, Rice University; rafaelv@rice.edu.
authors.forename: Rafael
authors.initials: R
authors.lastname: Verduzco
mesh_terms: D020724:Elastomers / Q000138:chemical synthesis*; D004560:Electricity; D050866:Liquid Crystals / Q000737:chemistry*; D053761:Nanocomposites; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D020724:Elastomers