Is biopolymer hair a multi-responsive smart material?

2017 ◽  
Vol 8 (1) ◽  
pp. 283-294 ◽  
Author(s):  
Xueliang Xiao ◽  
Jinlian Hu ◽  
Xiaoting Gui ◽  
Jing Lu ◽  
Hongsheng Luo
Keyword(s):  
Shape Memory ◽  
Uv Light ◽  
Smart Material ◽  
Structure Model ◽  
Switch Structure ◽  
Animal Hair ◽  
External Stimuli

A twin-netpoint-switch structure model for animal hair has been proposed for interpreting different shape memory abilities when exposure on different external stimuli, where a twin-netpoint/single-switch structure is for the stimulus of water, heat and UV-light, and a single-netpoint/twin-switch structure is for the stimulus of redox agent.

scholarly journals Combined light- and heat-induced shape memory behavior of anthracene-based epoxy elastomers

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yuzhan Li ◽  
Monojoy Goswami ◽  
Yuehong Zhang ◽  
Tuan Liu ◽  
Jinwen Zhang ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Shape Memory ◽  
Uv Light ◽  
Dynamic Mechanical Properties ◽  
Stimuli Responsive ◽  
Epoxy Monomer ◽  
Dynamics Simulations ◽  
External Stimuli

AbstractThe development of multi-stimuli-responsive shape memory polymers has received increasing attention because of its scientific and technological significance. In this work, epoxy elastomers with reversible crosslinks are synthesized by polymerizing an anthracene-functionalized epoxy monomer, a diepoxy comonomer, and a dicarboxylic acid curing agent. The synthesized elastomers exhibit active responses to both light and heat enabled by the incorporated anthracene groups. When exposed to 365 nm UV light, additional crosslinking points are created by the photo-induced dimerization of pendant anthracene groups. The formation of the crosslinking points increases modulus and glass transition temperature of the elastomers, allowing for the fixation of a temporary shape at room temperature. The temporary shape remains stable until an external heat stimulus is applied to trigger the scission of the dimerized anthracene, which reduces the modulus and glass transition temperature and allows the elastomers to recover their original shapes. The effects of external stimuli on the thermal and dynamic mechanical properties of the elastomers are investigated experimentally and are correlated with molecular dynamics simulations that reveal the changes of structure and dynamics of the anthracene molecules and flexible chains.

Three-dimensional Graphene Coated Shape Memory Polyurethane Foam with Fast Responsive Performance

2021 ◽  
Author(s):  
Tianjiao Wang ◽  
Jun Zhao ◽  
Chuanxin Weng ◽  
Tong Wang ◽  
Yayun Liu ◽  
...  
Keyword(s):  
Shape Memory ◽  
Polyurethane Foam ◽  
Three Dimensional ◽  
Shape Memory Polymers ◽  
Practical Applications ◽  
External Stimuli ◽  
Shape Memory Polyurethane

Shape memory polymers (SMPs) that change shapes as designed by external stimuli have become one of the most promising materials as actuators, sensors, and deployable devices. However, their practical applications...

scholarly journals Smart material using fiber Bragg grating transducers and shape memory alloy actuators

2012 ◽  
Author(s):  
L. Rodriguez-Cobo ◽  
A. Quintela ◽  
A. Cobo ◽  
J. M. Lopez-Higuera
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Fiber Bragg Grating ◽  
Smart Material ◽  
Bragg Grating

scholarly journals Stepwise activation of a class C GPCR begins with millisecond dimer rearrangement

2019 ◽  
Vol 116 (20) ◽  
pp. 10150-10155 ◽  
Author(s):  
Eugene O. Grushevskyi ◽  
Taulant Kukaj ◽  
Ralf Schmauder ◽  
Andreas Bock ◽  
Ulrike Zabel ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Metabotropic Glutamate Receptor ◽  
Uv Light ◽  
Initial Step ◽  
Intact Cells ◽  
Metabotropic Glutamate ◽  
Solution Exchange ◽  
Receptor Sites ◽  
Tm Domain ◽  
External Stimuli

G protein-coupled receptors (GPCRs) are key biological switches that transmit both internal and external stimuli into the cell interior. Among the GPCRs, the “light receptor” rhodopsin has been shown to activate with a rearrangement of the transmembrane (TM) helix bundle within ∼1 ms, while all other receptors are thought to become activated within ∼50 ms to seconds at saturating concentrations. Here, we investigate synchronous stimulation of a dimeric GPCR, the metabotropic glutamate receptor type 1 (mGluR1), by two entirely different methods: (i) UV light-triggered uncaging of glutamate in intact cells or (ii) piezo-driven solution exchange in outside-out patches. Submillisecond FRET recordings between labels at intracellular receptor sites were used to record conformational changes in the mGluR1. At millimolar ligand concentrations, the initial rearrangement between the mGluR1 subunits occurs at a speed of τ1 ∼ 1–2 ms and requires the occupancy of both binding sites in the mGluR1 dimer. These rapid changes were followed by significantly slower conformational changes in the TM domain (τ2 ∼ 20 ms). Receptor deactivation occurred with time constants of ∼40 and ∼900 ms for the inter- and intrasubunit conformational changes, respectively. Together, these data show that, at high glutamate concentrations, the initial intersubunit activation of mGluR1 proceeds with millisecond speed, that there is loose coupling between this initial step and activation of the TM domain, and that activation and deactivation follow a cyclic pathway, including—in addition to the inactive and active states—at least two metastable intermediate states.

scholarly journals Effective Transcutaneous Delivery of Hyaluronic Acid Using an Easy-to-Prepare Reverse Micelle Formulation

Cosmetics ◽  
2020 ◽  
Vol 7 (3) ◽  
pp. 52
Author(s):  
Shuto Kozaka ◽  
Ayaka Kashima ◽  
Rie Wakabayashi ◽  
Takahiro Nakata ◽  
Taro Ueda ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Reverse Micelle ◽  
Barrier Function ◽  
Uv Light ◽  
Skin Permeation ◽  
High Energy ◽  
Skin Permeability ◽  
Reverse Micellar System ◽  
Transcutaneous Delivery ◽  
External Stimuli

The skin loses its moisture with advancing age, causing cosmetic issues such as wrinkles. In addition, the loss of moisture leads to hypersensitivity to external stimuli such as UV light. Transcutaneous supplementation with hyaluronic acid (HA) is an effective and safe method of recovering the moisturizing function and elasticity of the skin. However, the transcutaneous delivery of HA remains challenging owing to the barrier function of the stratum corneum (SC) layer. To penetrate the SC barrier, we used a reverse micelle formulation that does not require high energy consumption processes for preparation. We aimed to enhance the skin permeability of HA by incorporating glyceryl monooleate—a skin permeation enhancer—into the formulation. A fluorescently-labeled HA-loaded reverse micelle formulation showed significantly enhanced permeation across Yucatan micro pig skin. Fourier transform infra-red spectroscopy of the surface of the skin treated with the reverse micelle formulation showed blue shifts of the CH2 symmetric/asymmetric stretching peaks, indicating a reduction in the barrier function of the SC. Further study revealed that HA was released from the reverse micelles at the hydrophobic/hydrophilic interface between the SC and the living epidermis. The results demonstrated that our reverse micellar system is an easy-to-prepare formulation for the effective transcutaneous delivery of HA.

Precipitates Formation in Ti-Ni Equiatomic Alloys due to Annealing Heat Treatment

2010 ◽  
Vol 643 ◽  
pp. 49-54 ◽  
Author(s):  
Carlos Augusto Nascimento Oliveira ◽  
Euclides Apolinário Cabral De Pina ◽  
Cezar Henrique Gonzalez ◽  
Carlos José de Araújo ◽  
U.S.L. Filho ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Martensitic Transformation ◽  
Shape Memory ◽  
Martensitic Transformations ◽  
Smart Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metallurgical Investigation ◽  
Annealing Heat Treatment ◽  
Annealing Heat

The use of smart material such as Ti-Ni in actuators application requires an intense mechanical and metallurgical investigation to understand its behavior. This paper studies martensitic transformation using DSC and X-ray diffraction techniques to compare shape memory parameters in Ti-50.2%Ni (A1) and equiatomic Ti-50.0%Ni (A2) Alloys. The as as-received samples were submitted to annealing at 400°C and 500°C for 24 hours then quenched in at 25°C. The influence of heat treatment on martensitic transformations temperatures and the appearance of R-phase were analyzed using DSC and X-ray diffraction.

scholarly journals Ni-Ti Shape Memory Alloy Coatings for Structural Applications: Optimization of HVOF Spraying Parameters

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Carmen De Crescenzo ◽  
Despina Karatza ◽  
Dino Musmarra ◽  
Simeone Chianese ◽  
Theocharis Baxevanis ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Large Scale ◽  
Thermal Spray Technology ◽  
Spray Parameters ◽  
Hvof Spraying ◽  
Structural Applications ◽  
External Stimuli ◽  
Steel Substrates ◽  
The Impact

This work aims at contributing to the development of a revolutionary technology based on shape memory alloy (SMA) coatings deposited on-site to large-scale metallic structural elements, which operate in extreme environmental conditions, such as steel bridges and buildings. The proposed technology will contribute to improve the integrity of metallic civil structures, to alter and control their mechanical properties by external stimuli, to contribute to the stiffness and rigidity of an elastic metallic structure, to safely withstand the expected loading conditions, and to provide corrosion protection. To prove the feasibility of the concept, investigations were carried out by depositing commercial NiTinol Ni50.8Ti (at.%) powder, onto stainless steel substrates by using high-velocity oxygen-fuel thermal spray technology. While the NiTinol has been known since decades, this intermetallic alloy, as well as no other alloy, was ever used as the SMA-coating material. Due to the influence of dynamics of spraying and the impact energy of the powder particles on the properties of thermally sprayed coatings, the effects of the main spray parameters, namely, spray distance, fuel-to-oxygen feed rate ratio, and coating thickness, on the quality and properties of the coating, in terms of hardness, adhesion, roughness, and microstructure, were investigated.

Development Smart/Nervous Material With Novel Sensor Embedding Techniques: A Review

2015 ◽  
Author(s):  
Asad Muhammad Butt ◽  
Samir Mekid
Keyword(s):  
Performance Improvement ◽  
Health Monitoring ◽  
Smart Material ◽  
Embedded Sensors ◽  
Clear Understanding ◽  
Coverage Area ◽  
Current Review ◽  
Fast Processing ◽  
External Stimuli ◽  
Force Pressure

The paper discusses recent attempts to support the development of nervous materials based on structural health monitoring, augmented with corrective actions using actuators against any external effect or impending failure within the structure. This configuration features embedded sensors inside materials of structural importance e.g. metal and composites that could include comprehensive monitoring in terms of coverage area of the structure, variety of parameters to be measured, types of signals received and with fast information processing capabilities. Fast processing of information would allow the smart material to respond quickly and effectively to any external stimuli e.g. force, pressure or temperature. A review is provided to establish grounds to work on novel methods to embed off-the-shelf sensors for the development of smart material/structures. Actuation options have not been considered in this current review. Existing embedding technologies are reviewed for the sake of refining direction of research and possibilities on improvement of plausible methods. It is envisaged throughout this review to establish a clear understanding of the existing methods and develop improved and alternatives for performance improvement when developing smart and nervous materials.

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