Dual-Mode Switching of Diffraction Gratings Based on Azobenzene- Polymer-Stabilized Liquid Crystals

2005 ◽  
Vol 17 (3) ◽  
pp. 370-374 ◽  
Author(s):  
X. Tong ◽  
G. Wang ◽  
A. Yavrian ◽  
T. Galstian ◽  
Y. Zhao
Keyword(s):  
Liquid Crystals ◽  
Diffraction Gratings ◽  
Mode Switching ◽  
Dual Mode ◽  
Azobenzene Polymer ◽  
Polymer Stabilized

New photoactive polymer and liquid-crystal materials

2004 ◽  
Vol 76 (7-8) ◽  
pp. 1499-1508 ◽  
Author(s):  
Yue Zhao
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Self Assembly ◽  
Diffraction Gratings ◽  
Thermoplastic Elastomers ◽  
Side Chain ◽  
Ferroelectric Liquid Crystals ◽  
Azobenzene Polymer ◽  
Photoactive Materials ◽  
Polymer Stabilized

The reversible trans–cis photoisomerization of azobenzene and azopyridine chromophore was used to design and exploit novel photoactive materials based on polymers and liquid crystals. This paper reviews our recent studies on several systems. These include azobenzene-containing thermoplastic elastomers that can be used to prepare mechanically tunable diffraction gratings, side-chain azopyridine polymers for combined self-assembly and photoactivity, azobenzene polymer-stabilized ferroelectric liquid crystals whose bulk alignment can be achieved by light with no need for surface orientation layers, and, finally, self-assembled photoactive liquid-crystal gels that can display light-induced reorganization leading to the formation of electrically switchable diffraction gratings.

Azobenzene polymer stabilized ferroelectric liquid crystals: simultaneous photopolymerization and photoalignment

2005 ◽  
Vol 32 (5) ◽  
pp. 599-607 ◽  
Author(s):  
Sonia Sévigny ◽  
Luc Bouchard ◽  
Shahrokh Motallebi ◽  
Yue Zhao
Keyword(s):  
Liquid Crystals ◽  
Ferroelectric Liquid Crystals ◽  
Azobenzene Polymer ◽  
Polymer Stabilized

Mesogenic linear azobenzene polymer-stabilized nematic liquid crystals

2011 ◽  
Vol 109 (6) ◽  
pp. 063505
Author(s):  
Arutyun Bagramyan ◽  
Olivier Thibault-Maheu ◽  
Tigran Galstian ◽  
André Bessette ◽  
Yue Zhao
Keyword(s):  
Liquid Crystals ◽  
Nematic Liquid Crystals ◽  
Azobenzene Polymer ◽  
Polymer Stabilized

Azobenzene-polymer-stabilized ferroelectric liquid crystals: photoalignment and morphology

2003 ◽  
Author(s):  
Yue Zhao ◽  
Nadine Paiement ◽  
Sonia Sevigny ◽  
Steve LeClair ◽  
Shahrokh Motallebi ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Ferroelectric Liquid Crystals ◽  
Azobenzene Polymer ◽  
Polymer Stabilized

scholarly journals Design, modeling, and demonstration of a new dual-mode back-assist exosuit with extension mechanism

2021 ◽  
Vol 2 ◽  
Author(s):  
Erik P. Lamers ◽  
Karl E. Zelik
Keyword(s):  
Biomechanical Model ◽  
Mode Switching ◽  
Design Parameters ◽  
Dual Mode ◽  
Extension Mechanism ◽  
Body Forces ◽  
Low Profile ◽  
Military Healthcare ◽  
The Moment ◽  
Practical Factors

Abstract Occupational exoskeletons and exosuits have been shown to reduce muscle demands and fatigue for physical tasks relevant to a variety of industries (e.g., logistics, construction, manufacturing, military, healthcare). However, adoption of these devices into the workforce has been slowed by practical factors related to comfort, form-factor, weight, and not interfering with movement or posture. We previously introduced a low-profile, dual-mode exosuit comprised of textile and elastic materials to address these adoption barriers. Here we build upon this prior work by introducing an extension mechanism that increases the moment arm of the exosuit while in engaged mode, then collapses in disengaged mode to retain key benefits related to being lightweight, low-profile, and unobstructive. Here we demonstrate both analytically and empirically how this extensible exosuit concept can (a) reduce device-to-body forces (which can improve comfort for some users and situations), or (b) increase the magnitude of torque assistance about the low back (which may be valuable for heavy-lifting jobs) without increasing shoulder or leg forces relative to the prior form-fitting exosuit. We also introduce a novel mode-switching mechanism, as well as a human-exosuit biomechanical model to elucidate how individual design parameters affect exosuit assistance torque and device-to-body forces. The proof-of-concept prototype, case study, and modeling work provide a foundation for understanding and implementing extensible exosuits for a broad range of applications. We envision promising opportunities to apply this new dual-mode extensible exosuit concept to assist heavy-lifting, to further enhance user comfort, and to address the unique needs of last-mile and other delivery workers.

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