Preparation of Soft Shape Memory Polymer and Its Application as a Compliant Thermal‐Triggered Gripper

Abstract

A shape memory polymer always experiences a large modulus change above and below its transition temperature. Cooling down below its transition temperature leads to a sharp modulus increase. That helps the temporary shape fixing, however, it also gives the material noncompliant character, which may be a harmful factor in some applications. In this work, an approach is proposed to prepare a soft shape memory polymer with low modulus even at low temperature. The realization of this polymer depends on the mixing of two raw materials through nano‐latex blending technique. By using styrene, meth acrylate, and n‐butyl acrylate as model monomer, two kinds of core–shell latexes are synthesized, which have a triblock structure as polystyrene‐b‐poly (styrene‐co‐meth acrylate)‐b‐polystyrene and polystyrene‐b‐poly (n‐butyl acrylate)‐b‐polystyrene, respectively. Blending in the unit of nano‐latex particle helps them mixing very homogenously and forms co‐continuous morphology. The blending ratio is tuned to prepare materials with modulus lower than 50 MPa at 20 °C, meanwhile with excellent shape memory performance. Such a soft shape memory polymer shows unique advantage as a compliant thermal‐triggered gripper to stick and place objects.

Beyond Human Hand: Shape-Adaptive and Reversible Magnetorheological Elastomer-Based Robot Gripper Skin

“…Meanwhile, several universal grippers based on soft or smart materials have been used recently owing to their promising features to achieve versatile and adaptive grasping, such as lightweightness, inexpensiveness, easy fabrication, and simple control. − Universal grippers based on soft smart materials possess sufficient force as well as reliable and rapid succession to grip various arbitrary objects. Furthermore, soft grippers continuously change their shape without requiring complex joints and then retain their shape under their grasping or lifting process.…”

Styrene‐butadiene‐styrene‐based shape memory polymers: Evolution and the current state of art

“…This results in a drop in the recovery (%) as the molecular weight of the PCL domains goes down, which is primarily attributed to the decrease in the entanglement density, thereby making the system brittle (eventually ruining the compatibility and homogeneity of the blend components). 120,121 Olefins such as low-density polyethylene (LDPE) and linear lowdensity polyethylene (LLDPE) are also used to blend with SBS in developing a robust shape memory polymer. [122][123][124] Youngkun et al had developed an SBS/LLDPE-based polymer system by crosslinking SBS with LLDPE via radiation (Figure 16).…”

Four-dimensional printed self-deploying circular structures with large folding ratio inspired by origami

“…Shape memory polymers (SMPs) are a kind of stimulus response material, which can restore its initial shape after deformation through the stimulation of external conditions such as thermal, electricity, light, and chemical induction (Du et al, 2017; Habault et al, 2013; Lai et al, 2018; Li et al, 2019; Zhao et al, 2015). Compared with shape memory alloy (SMA) and piezoelectric ceramic materials, SMP has the advantages of high strain recovery, low density, low cost, simple shape programming program, and so on.…”