Structure of nematic liquid crystalline elastomers under uniaxial deformation

Journal Article · Wed Feb 15 04:00:00 EST 2006 · Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics

DOI:https://doi.org/10.1103/PHYSREVE.73.0· OSTI ID:20778697

Fan, Zhang; Heiney, Paul A; Srinivasan, Amritha; Naciri, Jawad; Ratna, Banahalli ^[1]

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1. Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

We have used in situ x-ray diffraction and calorimetry to study liquid crystalline elastomers prepared using a one-step photopolymerization method. We used suspended weights to stretch free-standing crystalline elastomer films. With the mechanical stress parallel to the initial director, we observed a gradual nematic to isotropic transition with increasing temperature. The thermal evolution of the nematic order parameter on cooling, together with the observation of isotropic-nematic coexistence over a broad temperature range, suggests that the heterogeneity in the samples introduces a distribution of transition temperatures. With the mechanical stress perpendicular to the initial director, we observed both uniform director rotation and stripe formation, depending on the details of sample preparation.

• OSTI ID: 20778697
• Journal Information: Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, Journal Name: Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics Journal Issue: 2 Vol. 73; ISSN PLEEE8; ISSN 1063-651X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CALORIMETRY
COOLING
DEFORMATION
ELASTOMERS
EVOLUTION
FILMS
LIQUID CRYSTALS
ORDER PARAMETERS
PHASE TRANSFORMATIONS
SAMPLE PREPARATION
STRESSES
TEMPERATURE DEPENDENCE
TRANSITION TEMPERATURE
X-RAY DIFFRACTION