scholarly journals Shape memory polymer network with thermally distinct elasticity and plasticity

2016 ◽  
Vol 2 (1) ◽  
pp. e1501297 ◽  
Author(s):  
Qian Zhao ◽  
Weike Zou ◽  
Yingwu Luo ◽  
Tao Xie
Keyword(s):  
Shape Memory ◽  
Molecular Design ◽  
Shape Change ◽  
Shape Memory Polymer ◽  
Polymer Network ◽  
Stimuli Responsive ◽  
Responsive Materials ◽  
Device Applications ◽  
Temperature Ranges ◽  
Rational Molecular Design

Stimuli-responsive materials with sophisticated yet controllable shape-changing behaviors are highly desirable for real-world device applications. Among various shape-changing materials, the elastic nature of shape memory polymers allows fixation of temporary shapes that can recover on demand, whereas polymers with exchangeable bonds can undergo permanent shape change via plasticity. We integrate the elasticity and plasticity into a single polymer network. Rational molecular design allows these two opposite behaviors to be realized at different temperature ranges without any overlap. By exploring the cumulative nature of the plasticity, we demonstrate easy manipulation of highly complex shapes that is otherwise extremely challenging. The dynamic shape-changing behavior paves a new way for fabricating geometrically complex multifunctional devices.

Electro-thermo-mechanical behavior of carbon nanopaper shape memory polymer composites

2021 ◽  
pp. 1045389X2110188
Author(s):  
Veli Bugra Ozdemir ◽  
Kawai Kwok
Keyword(s):  
Mechanical Behavior ◽  
Shape Memory ◽  
Shape Change ◽  
Shape Memory Polymer ◽  
Axial Loading ◽  
Element Model ◽  
Close Correlation ◽  
Stimuli Responsive ◽  
Shape Memory Composites ◽  
Shape Programming

An electro-active composite based on carbon nanopaper (CNP) shape memory polymer (SMP) composite is proposed for actuating deployment of composite deployable structures. Carbon nanopaper shape memory composites are stimuli-responsive materials that can change between programmed shapes and the original shape by a voltage input. The proposed composite is a sandwich structure where the CNP layer acts as a flexible electrical heater when a voltage difference is applied. The shape change behavior of CNP-SMP composite presents a coupled electrical-thermal-structural problem. This paper presents a combined experimental, numerical, and analytical study of the time-dependent shape programming, stowage, and actuation of the CNP-SMP composite. The governing equations for the multiphysics behavior are derived. Characterization of the electrical and mechanical properties of the materials are carried out and employed in a nonlinear, fully coupled electrical-thermal-structural finite element model. Shape programming, stowage and actuation characteristics of the composite are investigated experimentally under axial loading. An analytical model is derived for the thermo-mechanical behavior of the composite which directly expresses the recovery over time through the creep compliance function. Close correlation is obtained between experimental measurements and numerical simulations. The proposed model can accurately predict the load and shape characteristics throughout programming, stowage, and actuation.

scholarly journals Effect of Crosslinkers on Optical and Mechanical Behavior of Chiral Nematic Liquid Crystal Elastomers

Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6193
Author(s):  
Kyosun Ku ◽  
Kyohei Hisano ◽  
Kyoko Yuasa ◽  
Tomoki Shigeyama ◽  
Norihisa Akamatsu ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Polymer Network ◽  
Molar Ratio ◽  
Stimuli Responsive ◽  
Breaking Strain ◽  
Responsive Materials ◽  
Sensor Applications ◽  
Color Changes ◽  
Chiral Nematic ◽  
Liquid Crystal Elastomers

Chiral nematic (N*) liquid crystal elastomers (LCEs) are suitable for fabricating stimuli-responsive materials. As crosslinkers considerably affect the N*LCE network, we investigated the effects of crosslinking units on the physical properties of N*LCEs. The N*LCEs were synthesized with different types of crosslinkers, and the relationship between the N*LC polymeric system and the crosslinking unit was investigated. The N*LCEs emit color by selective reflection, in which the color changes in response to mechanical deformation. The LC-type crosslinker decreases the helical twisting power of the N*LCE by increasing the total molar ratio of the mesogenic compound. The N*LCE exhibits mechano-responsive color changes by coupling the N*LC orientation and the polymer network, where the N*LCEs exhibit different degrees of pitch variation depending on the crosslinker. Moreover, the LC-type crosslinker increases the Young’s modulus of N*LCEs, and the long methylene chains increase the breaking strain. An analysis of experimental results verified the effect of the crosslinkers, providing a design rationale for N*LCE materials in mechano-optical sensor applications.

Blocking force measurement of shape memory polymer composite hinges for space deployable structures

2018 ◽  
Vol 29 (18) ◽  
pp. 3667-3678 ◽  
Author(s):  
Thanh Duc Dao ◽  
Nam Seo Goo ◽  
Woong Ryeol Yu
Keyword(s):  
Shape Memory ◽  
Polymer Composite ◽  
Mechanical Performance ◽  
Force Measurement ◽  
Shape Change ◽  
Shape Memory Polymer ◽  
Mass System ◽  
Manufacturing Method ◽  
Moment Arms ◽  
Repeated Test

This study introduces a method for measuring the blocking force of a shape memory polymer composite hinge to quantify the performance of a shape memory polymer composite hinge for space deployable structure applications. A detailed design of how to select heating elements for a self-deployable configuration is also suggested. The shape memory polymer composite hinge consists of two reverse carpenter shape memory polymer composite tapes that were made from carbon-epoxy fabric, shape memory polymer resin, and two heating elements. The heating elements were attached to the shape memory polymer composite tape using the composite manufacturing method, and they were used as the heating source in the deployment test. The blocking force and moment of the hinge were measured using a pulley–mass system setup to examine the mechanical performance of the hinge. During the test, the shape change was recorded with a camera to calculate the moment arms. While the blocking force was 7.21 N in the initial test, it decreased slightly with the working cycle and was 6.27 N in the repeated test. The maximum hinge moment was 0.47 N m in the repeated test. In addition, the results revealed that a pop-up phenomenon occurred at the middle period of deployment. These results confirm that the shape memory polymer composite hinge works well with heating elements and provide a guideline for performance evaluation of the shape memory polymer composite hinge.

scholarly journals Programming a crystalline shape memory polymer network with thermo- and photo-reversible bonds toward a single-component soft robot

2018 ◽  
Vol 4 (1) ◽  
pp. eaao3865 ◽  
Author(s):  
Binjie Jin ◽  
Huijie Song ◽  
Ruiqi Jiang ◽  
Jizhou Song ◽  
Qian Zhao ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Polymer Network ◽  
Single Component ◽  
Soft Robot

An annulus fibrosus closure device based on a biodegradable shape-memory polymer network

Biomaterials ◽  
2013 ◽  
Vol 34 (33) ◽  
pp. 8105-8113 ◽  
Author(s):  
Shahriar Sharifi ◽  
Theo G. van Kooten ◽  
Hendrik-Jan C. Kranenburg ◽  
Björn P. Meij ◽  
Marc Behl ◽  
...  
Keyword(s):  
Shape Memory ◽  
Annulus Fibrosus ◽  
Shape Memory Polymer ◽  
Polymer Network ◽  
Closure Device

Stimuli-responsive micro/nanoporous hairy skin for adaptive thermal insulation and infrared camouflage

2020 ◽  
Vol 7 (12) ◽  
pp. 3258-3265
Author(s):  
Ayoung Choe ◽  
Jeonghee Yeom ◽  
Yeju Kwon ◽  
Youngoh Lee ◽  
Young-Eun Shin ◽  
...  
Keyword(s):  
Shape Memory ◽  
Thermal Insulation ◽  
Shape Memory Polymer ◽  
Stimuli Responsive ◽  
Hairy Skin ◽  
Infrared Camouflage

A smart hairy skin with hiearchical micro/nanoporous shape memory polymer enables dynamically adaptive thermal insulation.

Thermo-mechanical Behavior of (Meth)Acrylate Shape-Memory Polymer Networks

2011 ◽  
Vol 1312 ◽  
Author(s):  
Carl P. Frick ◽  
Nishant Lakhera ◽  
Christopher M. Yakacki
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Polymer Network ◽  
Polymer Networks ◽  
Weight Fraction ◽  
Crosslinking Density ◽  
Mechanical Stiffness ◽  
Actuation Force ◽  
Order Of Magnitude ◽  
Cross Linker

ABSTRACTOur overall approach is based on developing a photocrosslinkable polymer network with a favorable shape-memory response, using polymer chemistry and crosslinking density to control thermo-mechanical properties. Three polymer networks were created and thermo-mechanically tested, each from tert-Butyl acrylate linear builder co-polymerized with a poly(ethylene glycol) dimethacrylate cross-linker. By systematically altering the molecular weight and the weight fraction of the cross-linker, it was possible to create three polymers that exhibited the same glass transition temperature, but varied by almost an order of magnitude in rubbery modulus. Therefore, the mechanical stiffness could be tailored to suit a given application. Recovery behavior of the polymers was characterized over a range of deformation temperatures. It has been implicitly assumed a linear relationship between Free-Strain (i.e. no actuation force) and Fixed-Stress (i.e. maximum actuation force), however, this has never been confirmed experimentally. The energy per unit volume performed by the shape-memory polymer was quantified, and observed to be a function of strain recovered. The maximum recoverable work was shown to increase with cross-linking density, although the overall efficiency is similar for all materials tested.

scholarly journals Constructing Donor-Resonance-Donor Molecules for Acceptor-Free Bipolar Organic Semiconductors

Research ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
He Jiang ◽  
Jibiao Jin ◽  
Zijie Wang ◽  
Wuji Wang ◽  
Runfeng Chen ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
High Performance ◽  
Molecular Design ◽  
Stimuli Responsive ◽  
Light Emitting ◽  
Deep Blue ◽  
Device Structures ◽  
Device Applications ◽  
Donor Acceptor ◽  
Organic Optoelectronic

Organic semiconductors with bipolar transporting character are highly attractive as they offer the possibility to achieve high optoelectronic performance in simple device structures. However, the continual efforts in preparing bipolar materials are focusing on donor-acceptor (D-A) architectures by introducing both electron-donating and electron-withdrawing units into one molecule in static molecular design principles. Here, we report a dynamic approach to construct bipolar materials using only electron-donating carbazoles connected by N-P=X resonance linkages in a donor-resonance-donor (D-r-D) structure. By facilitating the stimuli-responsive resonance variation, these D-r-D molecules exhibit extraordinary bipolar properties by positively charging one donor of carbazole in enantiotropic N+=P-X- canonical forms for electron transport without the involvement of any acceptors. With thus realized efficient and balanced charge transport, blue and deep-blue phosphorescent organic light emitting diodes hosted by these D-r-D molecules show high external quantum efficiencies up to 16.2% and 18.3% in vacuum-deposited and spin-coated devices, respectively. These results via the D-r-D molecular design strategy represent an important concept advance in constructing bipolar organic optoelectronic semiconductors dynamically for high-performance device applications.

scholarly journals Polydopamine coated shape memory polymer: enabling light triggered shape recovery, light controlled shape reprogramming and surface functionalization

2016 ◽  
Vol 7 (7) ◽  
pp. 4741-4747 ◽  
Author(s):  
Zhen Li ◽  
Xiaoyong Zhang ◽  
Shiqi Wang ◽  
Yang Yang ◽  
Benye Qin ◽  
...  
Keyword(s):  
Shape Memory ◽  
Surface Functionalization ◽  
Shape Recovery ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Dip Coating ◽  
Responsive Materials ◽  
Thermally Responsive

Simple dip-coating transforms thermally responsive shape memory polymers into photo-responsive materials and allows for shape engineering and surface functionalization.

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