Supramolecular Assembly of Shape Memory and Actuating Hydrogels for Programmable Shape Transformation

2022 ◽  
Author(s):  
Jie Zhuo ◽  
Baoyi Wu ◽  
Jiawei Zhang ◽  
Yu Peng ◽  
Huanhuan Lu ◽  
...  
Keyword(s):  
Shape Memory ◽  
Supramolecular Assembly ◽  
Shape Transformation

scholarly journals A paper-based microfluidic platform with shape-memory-polymer-actuated fluid valves for automated multi-step immunoassays

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Hao Fu ◽  
Pengfei Song ◽  
Qiyang Wu ◽  
Chen Zhao ◽  
Peng Pan ◽  
...  
Keyword(s):  
Shape Memory ◽  
Limit Of Detection ◽  
Shape Memory Polymer ◽  
Single Layer ◽  
Success Rates ◽  
Paper Test ◽  
Shape Transformation ◽  
Detection Mechanism ◽  
Microfluidic Platform ◽  
Tnf Α

Abstract Smart fluid manipulation with automatically controlled paper valves will enable automated and multi-step immunoassays on paper-based microfluidic devices. In this work, we present an integrated paper-based microfluidic platform with shape-memory polymer (SMP)-actuated fluid valves capable of automated colorimetric enzyme-linked immunosorbent assays (ELISAs). A single-layer microfluidic paper-based analytical device (μPAD) was designed to store all the reagents on the chip, and sequentially transfer reagents to a paper test zone following a specific ELISA protocol through automatic fluidic flow control by the multiple SMP-actuated valves. The actuation of a paper valve was based on the thermally responsive, duel-state shape transformation of a SMP sheet attached to the root of a paper cantilever beam for driving a hydrophilic paper bridge to connect and disconnect two paper channels. A portable colorimetric reader was developed to control the on-chip valve operations, quantify the colorimetric signal output, display the assay result, and wirelessly transmit the data to a smart phone for the application of telemedicine. Reliable operations of the paper valve and the entire μPAD were demonstrated with success rates of 97% and 93%, respectively. A detection mechanism for valve malfunction was designed and confirmed effective to identify any mal-operation of individual valves, thus rendering our platform reliable in real assays. For device calibration, we conducted direct ELISAs of rabbit IgG in phosphate-buffered saline (PBS), and achieved a low limit of detection (LOD) of 27 pM (comparable to that of standard and paper-based ELISAs). In order to demonstrate the clinical application of our multi-step immunoassay platform, we also conducted sandwich ELISAs to quantify the protein level of an inflammatory cytokine, namely tumor necrosis factor (TNF)-α, in surgically injured laryngeal tissues of rats. The protein levels of TNF-α were shown similar between the conventional and μPAD ELISAs.

scholarly journals Review of Magnetic Shape Memory Polymers and Magnetic Soft Materials

2021 ◽  
Vol 7 (9) ◽  
pp. 123
Author(s):  
Sanne J. M. van Vilsteren ◽  
Hooman Yarmand ◽  
Sepideh Ghodrat
Keyword(s):  
Shape Memory ◽  
Magnetic Particles ◽  
Shape Memory Polymers ◽  
Soft Materials ◽  
Detailed Knowledge ◽  
Magnetic Shape Memory ◽  
Shape Transformation ◽  
Memory Recovery ◽  
Constitutive Response ◽  
Near Future

Magnetic soft materials (MSMs) and magnetic shape memory polymers (MSMPs) have been some of the most intensely investigated newly developed material types in the last decade, thanks to the great and versatile potential of their innovative characteristic behaviors such as remote and nearly heatless shape transformation in the case of MSMs. With regard to a number of properties such as shape recovery ratio, manufacturability, cost or programming potential, MSMs and MSMPs may exceed conventional shape memory materials such as shape memory alloys or shape memory polymers. Nevertheless, MSMs and MSMPs have not yet fully touched their scientific-industrial potential, basically due to the lack of detailed knowledge on various aspects of their constitutive response. Therefore, MSMs and MSMPs have been developed slowly but their importance will undoubtedly increase in the near future. This review emphasizes the development of MSMs and MSMPs with a specific focus on the role of the magnetic particles which affect the shape memory recovery and programming behavior of these materials. In addition, the synthesis and application of these materials are addressed.

Aero-structural optimization of shape memory alloy-based wing morphing via a class/shape transformation approach

2017 ◽  
Vol 232 (15) ◽  
pp. 2745-2759 ◽  
Author(s):  
Pedro BC Leal ◽  
Marcelo A Savi ◽  
Darren J Hartl
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
High Performance ◽  
Optimization Problems ◽  
Shape Change ◽  
Shape Transformation ◽  
Baseline Design ◽  
Deformable Structure ◽  
Stall Angle ◽  
Wing Morphing

Because of the continuous variability of the ambient environment, all aircraft would benefit from an in situ optimized wing. This paper proposes a method for preliminary design of feasible morphing wing configurations that provide benefits under disparate flight conditions but are also each structurally attainable via localized active shape change operations. The controlled reconfiguration is accomplished in a novel manner through the use of shape memory alloy embedded skin components. To address this coupled optimization problem, multiple sub-optimizations are required. In this work, the optimized cruise and landing airfoil configurations are determined in addition to the shape memory alloy actuator configuration required to morph between the two. Thus, three chained optimization problems are addressed via a common genetic algorithm. Each analysis-driven optimization considers the effects of both the deformable structure and the aerodynamic loading experienced by the wing. Aerodynamic considerations are addressed via a two-dimensional panel method and each airfoil shape is generated by the so-called class/shape transformation methodology. It is shown that structurally and aerodynamically feasible morphing of a modern high-performance sailplane wing produces a 22% decrease in weight and significantly increases stall angle of attack and lift at the same landing velocity when compared to a baseline design that employs traditional control surfaces.

Tensile Failure of 55-Nitinol Wire

1975 ◽  
Vol 33 ◽  
pp. 46-47
Author(s):  
F. I. Grace
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Stoichiometric Composition ◽  
Tensile Failure ◽  
Initial State ◽  
Initial Shape ◽  
Nitinol Wire ◽  
Cscl Type ◽  
Shear Transformation

An interest in NiTi alloys with near stoichiometric composition (55 NiTi) has intensified since they were found to exhibit a unique mechanical shape memory effect at the Naval Ordnance Laboratory some twelve years ago (thus refered to as NITINOL alloys). Since then, the microstructural mechanisms associated with the shape memory effect have been investigated and several interesting engineering applications have appeared.The shape memory effect implies that the alloy deformed from an initial shape will spontaneously return to that initial state upon heating. This behavior is reported to be related to a diffusionless shear transformation which takes place between similar but slightly different CsCl type structures.

The 3-Dimensional Molecular Structure of the Actin Filament Revisited

1985 ◽  
Vol 43 ◽  
pp. 480-481
Author(s):  
U. Aebi ◽  
R. Millonig ◽  
H. Salvo
Keyword(s):  
Actin Filament ◽  
Supramolecular Assembly ◽  
Specimen Preparation ◽  
X Ray Diffraction ◽  
Single Filament ◽  
X Ray ◽  
3 Dimensional ◽  
Filament Diameter ◽  
Preparation Conditions ◽  
Apparent Diameter

To date, most 3-D reconstructions of undecorated actin filaments have been obtained from actin filament paracrystal data (for refs, see 1,2). However, due to the fact that (a) the paracrystals may be several filament layers thick, and (b) adjacent filaments may sustantially interdigitate, these reconstructions may be subject to significant artifacts. None of these reconstructions has permitted unambiguous tracing or orientation of the actin subunits within the filament. Furthermore, measured values for the maximal filament diameter both determined by EM and by X-ray diffraction analysis, vary between 6 and 10 nm. Obviously, the apparent diameter of the actin filament revealed in the EM will critically depend on specimen preparation, since it is a rather flexible supramolecular assembly which can easily be bent or distorted. To resolve some of these ambiguities, we have explored specimen preparation conditions which may preserve single filaments sufficiently straight and helically ordered to be suitable for single filament 3-D reconstructions, possibly revealing molecular detail.

TEM study of order, structure and defects of β and martensite in Cu-Al-Mn shape memory alloys

1990 ◽  
Vol 48 (4) ◽  
pp. 188-189
Author(s):  
J.M. Guilemany ◽  
F. Peregrin
Keyword(s):  
Shape Memory ◽  
Orthophosphoric Acid ◽  
Isopropyl Alcohol ◽  
Metastable Phase ◽  
Characteristic Temperature ◽  
Ethanol Solution ◽  
Order Structure ◽  
Thin Foils ◽  
Polycrystalline Alloys ◽  
Diamond Saw

The shape memory effect (SME) shown by Cu-Al-Mn alloys stems from the thermoelastic martensitic transformation occuring between a β (L2,) metastable phase and a martensitic phase. The TEM study of both phases in single and polycrystalline Cu-Al-Mn alloys give us greater knowledge of the structure, order and defects.The alloys were obtained by vacuum melting of Cu, Al and Mn and single crystals were obtained from polycrystalline alloys using a modified Bridgman method. Four different alloys were used with (e/a) ranging from 1.41 to 1.46 . Two different heat treatments were used and the alloys also underwent thermal cycling throughout their characteristic temperature range -Ms, Mf, As, Af-. The specimens were cut using a low speed diamond saw and discs were mechanically thinned to 100 μm and then ion milled to perforation at 4 kV. Some thin foils were also prepared by twin-jet electropolishing, using a (1:10:50:50) urea: isopropyl alcohol: orthophosphoric acid: ethanol solution at 20°C. The foils were examinated on a TEM operated at 200 kV.

Sign in / Sign up

Export Citation Format

Share Document