A review of shape memory alloy research, applications and opportunities

Recent advances in shape–memory polymers: Structure, mechanism, functionality, modeling and applications

Advances in soft robotics, materials science, and stretchable electronics have enabled rapid progress in soft grippers. Here, a critical overview of soft robotic grippers is presented, covering different material sets, physical principles, and device architectures. Soft gripping can be categorized into three technologies, enabling grasping by: a) actuation, b) controlled stiffness, and c) controlled adhesion. A comprehensive review of each type is presented. Compared to rigid grippers, end-effectors fabricated from flexible and soft components can often grasp or manipulate a larger variety of objects. Such grippers are an example of morphological computation, where control complexity is greatly reduced by material softness and mechanical compliance. Advanced materials and soft components, in particular silicone elastomers, shape memory materials, and active polymers and gels, are increasingly investigated for the design of lighter, simpler, and more universal grippers, using the inherent functionality of the materials. Embedding stretchable distributed sensors in or on soft grippers greatly enhances the ways in which the grippers interact with objects. Challenges for soft grippers include miniaturization, robustness, speed, integration of sensing, and control. Improved materials, processing methods, and sensing play an important role in future research.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/adma.201707035

Soft Robotic Grippers.

Recent progress in shape memory polymer: New behavior, enabling materials, and mechanistic understanding

A review of stimuli-responsive shape memory polymer composites

Stimulus-responsive shape memory materials: A review

Abstract After a short discussion of various shape memory related phenomena and the basic working mechanisms behind the shape memory effect (SME) in polymeric shape memory materials (SMMs), standard techniques and procedures to characterize these types of materials are reviewed in details (including the concerns in the selection of testing methods and parameters). Although the focus of this paper is on the heating-responsive SME, important issues in the chemo-responsive SME are addressed. Furthermore, some other shape memory related phenomena, such as various kinds of temperature memory effect (TME), and multiple-SME etc., and optimization of the shape memory performance of a shape memory polymer (SMP) via tailoring the programming parameters are included.

Characterization of polymeric shape memory materials

We have investigated the electric field effects in low resistance perpendicular magnetic tunnel junction (MTJ) devices and found that the electric field can effectively reduce the coercivity (Hc) of free layer (FL) by 30% for a bias voltage Vb = −0.2 V. In addition, the bias field (Hb) on free layer is almost linearly dependent on Vb yet independent on the device size. The demonstrated Vb dependences of Hc and Hb in low resistance MTJ devices present the potential to extend the scalability of the electric field assisted spin transfer torque magnetic random access memory and improve its access speed.

Electric field effects in low resistance CoFeB-MgO magnetic tunnel junctions with perpendicular anisotropy

A thermo-responsive shape memory polymeric material is reported, which is not only rubber-like from above to below its shape recovery temperature, but also has a repeatable thermal-assisted healing function The mechanisms behind both features are identified It is found that while micron-sized inclusions play a part in the shape memory effect (SME), tangled polymer chains contribute to the rubber-like phenomenon and repeatable thermal-assisted healing function atop the SME This tangling effect enables a perfect combination of high elasticity, SME and repeatable thermal-assisted healing to be simultaneously achieved

https://iopscience.iop.org/article/10.1088/0964-1726/21/11/115010/pdf

Rubber-like shape memory polymeric materials with repeatable thermal-assisted healing function

We investigate buckling phenomenon during shape recovery in a poly(methyl methacrylate) upon immersing in ethanol (chemo-responsive) and heating (thermo-responsive) The underlying mechanism is revealed and the influential factors are discussed Such buckling phenomenon is generic and applicable to all materials during shape recovery when certain conditions (as discussed here) are satisfied

C. C. Wang

Papers

Stimulus-responsive shape memory materials: A review

Characterization of polymeric shape memory materials

Electric field effects in low resistance CoFeB-MgO magnetic tunnel junctions with perpendicular anisotropy

Rubber-like shape memory polymeric materials with repeatable thermal-assisted healing function

Buckling of poly(methyl methacrylate) in stimulus-responsive shape recovery