scholarly journals Light-regulated molecular diffusion in a liquid crystal network

Soft Matter ◽  
2019 ◽  
Vol 15 (23) ◽  
pp. 4737-4742 ◽  
Author(s):  
Anping Cao ◽  
Roel J. H. van Raak ◽  
Dirk J. Broer
Keyword(s):  
Liquid Crystal ◽  
Molecular Diffusion ◽  
Mechanical Response ◽  
Shape Change ◽  
Polymer Network ◽  
Polymer Networks ◽  
Molecular Transport ◽  
Crystal Polymer ◽  
Generate Surface ◽  
Photomechanical Effect

Photo-responsive liquid crystal polymer networks offer promising means to generate useful functional devices, but many of them focus on their mechanical response so as to generate surface features or shape change. Here, we present the photomechanical effect of the polymer network for molecular transport purposes.

Photoresponsive Azobenzene Liquid Crystal Polymer Networks: In Situ Photogenerated Stress Measurement

2010 ◽  
Author(s):  
Yanira Torres ◽  
Timothy White ◽  
Amber McClung ◽  
William Oates
Keyword(s):  
Liquid Crystal ◽  
Stress Measurement ◽  
Polymer Network ◽  
Polymer Networks ◽  
Liquid Crystal Polymer ◽  
Polymerization Process ◽  
Polarization Angle ◽  
Structure Property ◽  
Crystal Polymer ◽  
Azobenzene Mesogens

Azobenzene liquid crystal polymers and polymer networks are adaptive materials capable of converting light into mechanical work. Often, the photomechanical output of the azobenzene liquid crystal network (azo-LCN) is observed as a bending cantilever. The response of these materials can be either static (e.g. a simple bending cantilever) or dynamic (e.g. oscillating cantilever of 20–270 Hz). The resulting photomechanical output is dependent upon the domain orientation of the polymer network and the wavelength and polarization of the actinic light. Polydomain azobenzene liquid crystal polymer networks, which have the capability of bending both backwards and forwards with the change of polarization angle, are of particular interest. In the current study, three azo-LCNs are compared — two of them are equivalent in all respects except for one contains pendant azobenzene mesogens (1azo, azo-monoacrylate) and the other contains crosslinked azobenzene mesogens (2azo, azo-diacrylate). The third specimen has a combination of both mesogens. The mechanical behavior at different temperatures and examination of structure-property relationships in the polymerization process, including curing temperatures and liquid crystal cell alignment rubbing methods, were explored. Using dynamic mechanical analysis (DMA) the mechanical properties and the photogenerated stress and strain in the polymer are examined. It is found the differences in chemistry do correlate to small variation in the speed of photodirected bending, elastic modulus, and glass transition temperature. Despite these differences, all three azo-LCNs display nearly equivalent photogenerated stresses.

scholarly journals Mechanical adaptability of artificial muscles from nanoscale molecular action

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Federico Lancia ◽  
Alexander Ryabchun ◽  
Anne-Déborah Nguindjel ◽  
Supaporn Kwangmettatam ◽  
Nathalie Katsonis
Keyword(s):  
Liquid Crystal ◽  
Mechanical Response ◽  
Polymer Network ◽  
Soft Materials ◽  
Molecular Switches ◽  
Polymer Materials ◽  
Artificial Muscles ◽  
Shape Transformation ◽  
Crystal Polymer ◽  
Molecular Action

Abstract The motion of artificial molecular machines has been amplified into the shape transformation of polymer materials that have been compared to muscles, where mechanically active molecules work together to produce a contraction. In spite of this progress, harnessing cooperative molecular motion remains a challenge in this field. Here, we show how the light-induced action of artificial molecular switches modifies not only the shape but also, simultaneously, the stiffness of soft materials. The heterogeneous design of these materials features inclusions of free liquid crystal in a liquid crystal polymer network. When the magnitude of the intrinsic interfacial tension is modified by the action of the switches, photo-stiffening is observed, in analogy with the mechanical response of activated muscle fibers, and in contrast to melting mechanisms reported so far. Mechanoadaptive materials that are capable of active tuning of rigidity will likely contribute to a bottom-up approach towards human-friendly and soft robotics.

Liquid Crystal Polymer Networks and Elastomers for Light‐Fueled Robotics

2018 ◽  
pp. 197-226 ◽  
Author(s):  
Hao Zeng ◽  
Markus Lahikainen ◽  
Owies M. Wani ◽  
Alex Berdin ◽  
Arri Priimagi
Keyword(s):  
Liquid Crystal ◽  
Polymer Networks ◽  
Liquid Crystal Polymer ◽  
Crystal Polymer

scholarly journals Actuators: Programmable 3D Shape Changes in Liquid Crystal Polymer Networks of Uniaxial Orientation (Adv. Funct. Mater. 37/2018)

2018 ◽  
Vol 28 (37) ◽  
pp. 1870259
Author(s):  
Li Yu ◽  
Hamed Shahsavan ◽  
Geoffrey Rivers ◽  
Che Zhang ◽  
Pengxiang Si ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Polymer Networks ◽  
Liquid Crystal Polymer ◽  
3D Shape ◽  
Crystal Polymer ◽  
Uniaxial Orientation ◽  
Shape Changes

scholarly journals White-Light OLEDs Using Liquid Crystal Polymer Networks

2008 ◽  
Vol 20 (11) ◽  
pp. 3579-3586 ◽  
Author(s):  
Alicia Liedtke ◽  
Mary O’Neill ◽  
Anke Wertmöller ◽  
Stuart P. Kitney ◽  
Stephen M. Kelly
Keyword(s):  
Liquid Crystal ◽  
White Light ◽  
Polymer Networks ◽  
Liquid Crystal Polymer ◽  
Crystal Polymer
Sign in / Sign up

Export Citation Format

Share Document