Ductile Shape-Memory Polymer Composite with Enhanced Shape Recovery Ability

Abstract

In recent years, shape-memory polymers (SMPs) have received extensive attention to be used as actuators in a broad range of applications such as medical and robotic devices. Their ability to recover large deformations and their capability to be stimulated remotely have made SMPs a superior choice among different smart materials in various applications. In this study, a ductile SMP composite with enhanced shape recovery ability is synthesized and characterized. This SMP composite is made by a mixture of acrylate-based crosslinkers and monomers, as well as polystyrene (PS) with UV curing. The composite can achieve almost 100% shape recovery in 2 s by hot water or hot air. This shape recovery speed is much faster than typical acrylate-based SMPs. In addition, the composite shows excellent ductility and viscoelasticity with reduced hardness. Molecular dynamics (MD) simulations are performed for understanding the curing mechanism of this composite. With the combination of the experimental and computational works, this study paves the way in front of designing and optimizing the future SMP devices.

Bistable and Multistable Actuators for Soft Robots: Structures, Materials, and Functionalities

“…There are different kinds of SMPs in terms of their actuation methods, such as thermo-responsive, photo-responsive, and chemo-responsive. [78,148,149] Among them, thermo-responsive SMPs are one of the most commonly used for soft actuators. When the temperature is beyond the transition temperature, the SMPs become softer and tend to recover to their permanent shapes.…”

“…They can achieve bending, folding, twist, and contraction motions. [150,151] Despite the promise, thermal-responsive SMPs have two major drawbacks: One is the small output force due to its materials compliance, and the other is the slow actuation time or speed (from seconds to several minutes [77,78] ) with fast heating but slow cooling processes. Meanwhile, thermo-responsive shape memory alloys (SMAs) are also often used in soft robotics to generate contraction and elongation motion.…”

“…[ 67 ] During the snap‐through process, a large deflection or dramatic shape change occurs within a fast timescale of several to tens of milliseconds due to the sudden release of stored strain energy, which generates a large stroke force while under low actuation energy and small restoring forces. Thus, snap through provides a promising way to overcome the intrinsic limitations of small forces in most soft actuators due to the extreme compliance of their constituent soft materials, as well as, their slow responses due to the large deformation in hyperelastic soft materials during actuation (e.g., soft pneumatic actuators [ 44 ] ) or the prolonged deformation recovering process during de‐actuation (e.g., slow cooling in soft thermal actuators [ 77,78 ] ). Leveraging snap‐through instabilities for amplified force and faster response in soft actuators have demonstrated promising robotic applications in fast locomotion both on ground and under water, [ 68,69 ] jumping on ground and on water, [ 70 ] and fast griping or catching of falling objects.…”

Development of Trans-1,4-Polyisoprene Shape-Memory Polymer Composites Reinforced with Carbon Nanotubes Modified by Polydopamine

“…Shape-memory polymer (SMP) refers to a type of smart polymer that can return to its initial shape from a temporary deformed shape under external stimuli such as heat, light, electricity, magnetism, pH value, metal ions, and many other physical and chemical stimuli [ 1 , 2 , 3 ]. Because of their unique shape-recovery function, SMPs have broad application prospects in many fields, including biological medical devices, aerospace engineering, textiles, and anti-counterfeiting [ 4 , 5 , 6 ]. Thermally induced SMP is an important branch of shape-memory polymer stimulation that has been widely studied and has many industrial applications [ 7 , 8 , 9 ].…”

Frequency manipulation of a light-activated shape-memory polymer-laminated cylindrical shell

“…Smart materials [1][2][3][4][5] are widely utilised in the fields of architecture, automobiles, aeronautics and astronautics, biomedical devices, active control [6][7][8] and intelligent sensors. Shape-memory material, a type of smart material that can be potentially used for active vibration control, is particularly suitable for functioning in sensors and actuators.…”