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A Triple‐Shape Memory Material via Thermal Responsive Behavior of Liquid Crystalline Network Incorporating Main‐Chain/Side‐Chain LC Units
Author(s) -
Chen Guokang,
Zhang Qian,
Lu Maoping,
Liu Yingchun,
Wang Shan,
Wu Kun,
Lu Mangeng
Publication year - 2019
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201900059
Subject(s) - differential scanning calorimetry , fourier transform infrared spectroscopy , monomer , materials science , side chain , polymer , liquid crystal , shape memory alloy , polymer chemistry , chemical engineering , composite material , thermodynamics , physics , optoelectronics , engineering
In the last several years, multiple‐shape memory liquid crystalline networks (LCNs) have received more and more attention due to the basic theoretical research on them and their wide potential applications. In this article, a novel main‐chain/side‐chain liquid crystalline monomer and its corresponding polymer networks based on the thiol‐ene click reaction are reported. Properties of the synthesized liquid crystalline monomer are well studied with nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectra, differential scanning calorimetry (DSC), and polarized optical microscopy (POM). The as‐prepared free‐standing LCN films are investigated well by FTIR, DSC, POM, and X‐ray diffraction (XRD), which show them having good liquid crystalline properties. Tensile test and dynamical mechanical analysis (DMA) results indicate the LCN films have excellent thermal mechanical properties. By adjusting the crosslinking densities, LCN films exhibit two thermal transition temperatures ( T g and T NI ) that can be utilized to trigger the triple‐shape memory behaviors. The cyclic thermal mechanical analysis conducted by DMA reveals that LCN films exhibit good triple‐shape memory properties with high‐shape fixity ratio ( R f (S1→S2) is 99.2% and R f (S2→S3) is 99.3%) and shape recovery ratio ( R r (S3→S2) is 92.4% and R r (S2→S1) is 98.5%).