Processing of Self‐Healing Polymers for Soft Robotics

Abstract

Soft robots are, due to their softness, inherently safe and adapt well to unstructured environments. However, they are prone to various damage types. Self‐healing polymers address this vulnerability. Self‐healing soft robots can recover completely from macroscopic damage, extending their lifetime. For developing healable soft robots, various formative and additive manufacturing methods have been exploited to shape self‐healing polymers into complex structures. Additionally, several novel manufacturing techniques, noted as (re)assembly binding techniques that are specific to self‐healing polymers, have been created. Herein, the wide variety of processing techniques of self‐healing polymers for robotics available in the literature is reviewed, and limitations and opportunities discussed thoroughly. Based on defined requirements for soft robots, these techniques are critically compared and validated. A strong focus is drawn to the reversible covalent and (physico)chemical cross‐links present in the self‐healing polymers that do not only endow healability to the resulting soft robotic components, but are also beneficial in many manufacturing techniques. They solve current obstacles in soft robots, including the formation of robust multi‐material parts, recyclability, and stress relaxation. This review bridges two promising research fields, and guides the reader toward selecting a suitable processing method based on a self‐healing polymer and the intended soft robotics application.

A Healable Resistive Heater as a Stimuli-Providing System in Self-Healing Soft Robots

“…As seen in Fig. 11, the air chambers are first manufactured via compression moulding of grinded elastomer [44]. The heater is then sandwiched between layers of the DPBM-FT5000-r0.5 elastomer and placed in an oven at 130°C.…”

Viscoelastic Characterization of a Thermoplastic Elastomer Processed through Material Extrusion

“…Numerous studies investigated the different combinations of manufacturing parameters regarding the final mechanical behavior of the samples [ 1 , 2 ]; in particular, combinations of layer height, build orientation, manufacturing velocity, and temperature are the most commonly analyzed. Due to the versatility of MEX for manufacturing different geometries, this technology is used in several applications, such as the manufacture of conductive carbon nanomaterials and metals mixed with a thermoplastic [ 3 ], biomedical implants made of thermoplastics with high-temperature stability and high mechanical strength such as PAEK [ 4 ], and soft robotics by using flexible filament or thermoplastic elastomers (TPE) [ 5 ]. In fact, many research groups are focusing their studies on TPEs due to their properties in flexibility and their good mechanical behavior.…”

Near-Infrared-Light-Assisted Self-Healing Graphene-Thermopolyurethane Composite Films

“…In recent years, the advancement of wearable electronic devices, which use self-activating and self-adjusting systems, has raised new requirements for self-healing polymers [ 26 , 27 , 28 ]. Among them, self-healing thermoplastic polyurethane (TPU), as a block copolymer consisting of alternating sequences of hard and soft segments used in the automotive industry, electronics, medical supplies, coatings, and sports equipment, has made a considerable contribution to the service life and recyclability of TPU.…”