Desynchronized Liquid Crystalline Network Actuators with Deformation Reversal Capability

Abstract Liquid crystalline network (LCN) actuator normally deforms upon thermally or optically induced order-disorder phase transition, switching once between two shapes (shape-1 in LC phase and shape-2 in isotropic state) for each stimulation on/off cycle. Herein, we report a novel type of LCN actuator that deforms from shape-1 to shape-2 and then reverses the deformation direction back to shape-1 or to a new shape-3 on heating or under light only, meaning that the actuator can complete the shape switch twice for one stimulation on/off cycle. The deformation reversal capability is obtained with a monolithic LCN actuator whose two sides are made to start deforming at different temperatures and exerting different reversible strains, which can be realized through asymmetrical crosslinking and/or asymmetrical stretching of the two sides in preparing the LCN actuator. This desynchronized actuation strategy offers new possibilities in developing light-fueled LCN soft robots. In particular, the multi-stage bidirectional shape change can be used to achieve multimodal, light-driven locomotion with different moving speeds from the same LCN actuator by simply varying the light on/off times to confine shape switch in a specific sub-stage.

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Desynchronized liquid crystalline network actuators with deformation reversal capability

Nature Communications ◽

10.1038/s41467-021-20938-6 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Yao-Yu Xiao ◽

Zhi-Chao Jiang ◽

Jun-Bo Hou ◽

Yue Zhao

Keyword(s):

Phase Transition ◽

Liquid Crystalline ◽

Shape Change ◽

Soft Robots ◽

Disorder Phase Transition ◽

Isotropic State ◽

Multi Stage ◽

Different Temperatures ◽

Two Sides ◽

Optically Induced

AbstractLiquid crystalline network (LCN) actuator normally deforms upon thermally or optically induced order-disorder phase transition, switching once between two shapes (shape 1 in LC phase and shape 2 in isotropic state) for each stimulation on/off cycle. Herein, we report an LCN actuator that deforms from shape 1 to shape 2 and then reverses the deformation direction to form shape 3 on heating or under light only, thus completing the shape switch twice for one stimulation on/off cycle. The deformation reversal capability is obtained with a monolithic LCN actuator whose two sides are made to start deforming at different temperatures and exerting different reversible strains, by means of asymmetrical crosslinking and/or asymmetrical stretching. This desynchronized actuation strategy offers possibilities in developing light-fueled LCN soft robots. In particular, the multi-stage bidirectional shape change enables multimodal, light-driven locomotion from the same LCN actuator by simply varying the light on/off times.

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Rheological Properties of the Reverse Mesophases of the Pluronic L64/P-Xylene/Water System

Applied Rheology ◽

10.1515/arh-2004-0018 ◽

2004 ◽

Vol 14 (6) ◽

pp. 315-323 ◽

Cited By ~ 1

Author(s):

Luigi Coppola ◽

Domenico Gabriele ◽

Isabella Nicotera ◽

Cesare Oliviero

Keyword(s):

Phase Transition ◽

Crystalline Phase ◽

Liquid Crystalline ◽

Ternary Phase Diagram ◽

Water System ◽

Water Concentration ◽

Liquid Crystalline Phase ◽

Lamellar Phases ◽

Different Temperatures ◽

Mechanical Spectra

Abstract The behaviour of reverse micellar solution and reverse hexagonal and lamellar liquid crystal phases in pluronic L64/water/p-xylene ternary system was investigated by rheological techniques. Samples with an increasing water content along the amphiphilic copolymer-lean side of the ternary phase diagram were analysed at different temperatures and a different behaviour was evidenced by both dynamic and steady tests for each considered phase, depending on the morphology of structure (micellar, lamellar, hexagonal phases). It was observed that the reverse micelles size increases with increasing water concentration and decreases with increasing temperature, without any phase transition. On the contrary the normal micelles become anisometric on temperature, showing a transition to a liquid crystalline phase. The observed mechanical spectra of the liquid crystalline phases are typical of hexagonal and lamellar phases according to the literature [1, 2]. A phase transition with temperature was found for both liquid crystalline phase (lamellar and hexagonal) by rheological tests and was confirmed by ocular inspection.

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The structure of membranes and membrane proteins embedded in amorphous ice

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100122563 ◽

1992 ◽

Vol 50 (1) ◽

pp. 432-433

Author(s):

Uwe Lücken ◽

Joachim Jäger

Keyword(s):

Phase Transition ◽

Transition Temperature ◽

Membrane Proteins ◽

Phase Transition Temperature ◽

Lipid Vesicles ◽

Freezing Stress ◽

Amorphous Ice ◽

Different Temperatures ◽

Band Pass ◽

Lipid Polymorphism

TEM imaging of frozen-hydrated lipid vesicles has been done by several groups Thermotrophic and lyotrophic polymorphism has been reported. By using image processing, computer simulation and tilt experiments, we tried to learn about the influence of freezing-stress and defocus artifacts on the lipid polymorphism and fine structure of the bilayer profile. We show integrated membrane proteins do modulate the bilayer structure and the morphology of the vesicles.Phase transitions of DMPC vesicles were visualized after freezing under equilibrium conditions at different temperatures in a controlled-environment vitrification system. Below the main phase transition temperature of 24°C (Fig. 1), vesicles show a facetted appearance due to the quasicrystalline areas. A gradual increase in temperature leads to melting processes with different morphology in the bilayer profile. Far above the phase transition temperature the bilayer profile is still present. In the band-pass-filtered images (Fig. 2) no significant change in the width of the bilayer profile is visible.

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Order-disorder phase transition of NH4AlF4 through Raman scattering investigations

Journal de Physique ◽

10.1051/jphys:01985004603043500 ◽

1985 ◽

Vol 46 (3) ◽

pp. 435-445 ◽

Cited By ~ 11

Author(s):

M. Couzi ◽

P. Rocquet ◽

J.L. Fourquet

Keyword(s):

Phase Transition ◽

Raman Scattering ◽

Disorder Phase Transition

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Structure determination of sodium nitrate near the order-disorder phase transition

Journal de Physique ◽

10.1051/jphys:019840045080131700 ◽

1984 ◽

Vol 45 (8) ◽

pp. 1317-1327 ◽

Cited By ~ 15

Author(s):

J. Lefebvre ◽

R. Fouret ◽

C.M.E. Zeyen

Keyword(s):

Phase Transition ◽

Sodium Nitrate ◽

Structure Determination ◽

Disorder Phase Transition

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ORDER-DISORDER PHASE TRANSITION OF Au(110)-(1x2) RECONSTRUCTION

Le Journal de Physique Colloques ◽

10.1051/jphyscol:1988647 ◽

1988 ◽

Vol 49 (C6) ◽

pp. C6-269-C6-273 ◽

Cited By ~ 1

Author(s):

H. Q. NGUYEN ◽

Y. KUK ◽

P. J. SILVERMAN

Keyword(s):

Phase Transition ◽

Disorder Phase Transition

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Synthesis and Properties of Biodegradable Liquid Crystalline Poly(ester-Urethane)s Based on Poly(L-Lactic Acid)

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.652-654.459 ◽

2013 ◽

Vol 652-654 ◽

pp. 459-462

Author(s):

Ya Tong Guo ◽

Zhu Zheng ◽

Zhen Qi Hou ◽

Jie Du

Keyword(s):

Phase Transition ◽

Thermal Stability ◽

Lactic Acid ◽

Physical Properties ◽

Liquid Crystalline ◽

Degradation Rate ◽

Hydrolytic Degradation ◽

Hexamethylene Diisocyanate ◽

Solution Polymerization ◽

Phase Transition Temperatures

A series of biodegradable segmented liquid crystalline poly(ester-urethane)s were prepared by solution polymerization of poly(L-lactic acid) (PLLA), mesogenic diol prepolymer poly(butylene terephthaloyldioxy dibenzoates) (MD), and hexamethylene diisocyanate (HDI). The MD content was varied from 0 to 40 mol% so that the effects of the mesogen content on the thermal and physical properties, and hydrolytic degradation were examined respectively. It was found that introducing mesogens units could increase the thermal stability and the elastic properties, while reduced the phase transition temperatures and the hydrolytic degradation rate.

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Phase management in single-crystalline vanadium dioxide beams

Nature Communications ◽

10.1038/s41467-021-24527-5 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Run Shi ◽

Yong Chen ◽

Xiangbin Cai ◽

Qing Lian ◽

Zhuoqiong Zhang ◽

...

Keyword(s):

Phase Transition ◽

Vanadium Dioxide ◽

Temperature Phase ◽

Metal Insulator ◽

Single Crystalline ◽

Submicron Scale ◽

Engineering Strategy ◽

Improved Performance ◽

Effective Phase ◽

Two Sides

AbstractA systematic study of various metal-insulator transition (MIT) associated phases of VO2, including metallic R phase and insulating phases (T, M1, M2), is required to uncover the physics of MIT and trigger their promising applications. Here, through an oxide inhibitor-assisted stoichiometry engineering, we show that all the insulating phases can be selectively stabilized in single-crystalline VO2 beams at room temperature. The stoichiometry engineering strategy also provides precise spatial control of the phase configurations in as-grown VO2 beams at the submicron-scale, introducing a fresh concept of phase transition route devices. For instance, the combination of different phase transition routes at the two sides of VO2 beams gives birth to a family of single-crystalline VO2 actuators with highly improved performance and functional diversity. This work provides a substantial understanding of the stoichiometry-temperature phase diagram and a stoichiometry engineering strategy for the effective phase management of VO2.

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