Orientation behaviour of the minor director of homeotropically oriented nematic elastomers in mechanical fields

Enabling and Localizing Omnidirectional Nonlinear Deformation in Liquid Crystalline Elastomers

“…[2][3][4][5] Often, these approaches have focused on assimilating the properties of multiple materials in a single structural element. [13,16,17] Here, we extend from prior examinations [18][19][20][21] by employing newly developed material chemistry [6] to prepare and examine elastomeric (with T g < 25 °C) LCE films in the homeotropic orientation (i.e., the mesogens are aligned orthogonal to the film surface, Figure 1d). By patterning periodic tessellations of director orientation within the materials, the Poisson's ratio can be reduced to nearly zero over more than 10% global deformation.…”

Recent NMR Studies of Thermotropic Liquid Crystals

“…Some studies of deuterium T 1Z and T 2 relaxation time measurements have also been reported on LSCE samples [326,327]. Most DNMR studies of selectively deuterated LSCEs show broader spectra in samples containing deuterated crosslinkers [325,327] versus deuterated mesogens [326,328] or doped LSCEs [329]. Measurements and analyses of T 2 relaxation times in the I (PN) and N phases have been done on LSCE films containing deuterated crosslinkers.…”

Brief overview on2H NMR studies of polysiloxane‐based side‐chain nematic elastomers

“…Most of 2 H NMR studies on selectively 2 H-labeled LSCEs put in evidence broader spectra in samples containing deuterated crosslinkers [8,20,28] with respect to deuterated mesogens [16,19] or doped LSCEs. [9,17] This finding, observed both in the isotropic and in the nematic phases, leads to several studies, based on measurements and analysis of T 2 relaxation times, on LSCE films prepared with deuterated crosslinkers.…”

“…In particular, several works based on 2 H NMR spectroscopy have been published about the thermodynamic and thermo‐mechanic characterization of the mesophase transition in monodomain and polydomain LCE samples, the phase biaxiality of monodomain LCEs and their reorientational and dynamic features …”

“…Many efforts have been spent in the recent years while trying to understand the relationship between the macroscopic properties of LCEs and those of their molecular subunits, and the main steps forwards came recently from NMR investigations. [8,9] In particular, several works based on 2 H NMR spectroscopy have been published about the thermodynamic and thermo-mechanic characterization [10,11] of the mesophase transition in monodomain [12,13] and polydomain [14,15] LCE samples, the phase biaxiality of monodomain LCEs [16,17] and their reorientational [18,19] and dynamic features. [20,21] Most of these NMR investigations were performed on well-aligned monodomain LCE films having a nematic phase and prepared according to the so-called two-step crosslinking procedure introduced by Kupfer and Finkelmann [22] in 1991.…”