Autonomous self-healing hydrogel with anti-drying properties and applications in soft robotics

Abstract

Mimicking nature's self-healing ability has always been desired in science, especially when devices accumulate damage over time with performance, including the loss of function due to deterioration. SHAP (Self-Healing AETA([2-(acryloyloxy)ethyl]trimethylammonium chloride)based Polymer), a hydrogel with autonomous self-healing ability that can be applied for the development of a pneumatic artificial muscle, is presented here. Unlike other self-healing hydrogels, SHAP does not require any external stimulus to self-heal and it presents outstanding anti-drying properties. Few-layer graphene is also incorporated into the polymer network of the hydrogel in order to study the possible influence that the nanomaterial has on the properties of the scaffolds. The mechanical behavior and the self-healing abilities of the resulting hydrogels are analyzed. Moreover, the mechanism of self-healing is discussed in terms of experimental results and theoretical calculations. The data suggest a mechanism based on strong hydrogen-bonding interactions between the water molecules that remain inside SHAP, which keeps the material wet and soft under ambient conditions. Finally, the development of a SHAP-based artificial muscle is presented. The results show good performance of the healed artificial muscles after damage, even with healing periods as short as 10 minutes.

Environmentally Compatible Wearable Electronics Based on Ionically Conductive Organohydrogels for Health Monitoring with Thermal Compatibility, Anti‐Dehydration, and Underwater Adhesion

“…Dehydration after long‐term use remains a great challenge for soft and wearable electronics in practical applications, which may result in structural as well as functional failure of electronics due to moisture loss, hampering their long‐term use during wearable health monitoring. [ 20,40 ] To characterize anti‐dehydration property of L‐PAA‐OH, mechanical performance and conductivity are tested after long‐term use.…”

A review on self-healing polymers for soft robotics

“…SupraPolix presented that FFF can be used to print elastomers using hydrogen interactions into high resolution 3D parts with fast healing capacities at room temperature (225) (Figure 7D). A. Lopez Diaz et al (226,227) constructed an artificial muscle based on the commonly used McKibben design out of a hydrogen-bonded network, allowing to heal punctures and cuts without the need of a temperature increase in 24 hours, but with a limited healing efficiency of around 65 %.…”

Recent progress in conductive self‐healing hydrogels for flexible sensors

“…Hydrogen bonding is a common noncovalent interaction for fabricating self‐healing hydrogels, and the associated self‐healing mechanism is shown in Figure 6A 70–72 . For example, a novel conductive self‐healing hydrogel was prepared by using maleic acid (MA), choline chloride (ChCl), acrylamide (AAm) and choline chloride 65 .…”

“…Hydrogen bonding is a common noncovalent interaction for fabricating self-healing hydrogels, and the associated self-healing mechanism is shown in Figure 6A. [70][71][72] For example, a novel conductive self-healing hydrogel was prepared by using maleic acid (MA), choline chloride (ChCl), acrylamide (AAm) and choline chloride. 65 Owing to a great quantity of dynamic hydrogen bonding contributed by sufficient COOH, NH 2 and OH in the network of poly (PDES), as shown in Figure 6B, the hydrogels possess the ability to autonomously self-heal after being damaged with a self-healing efficiency at 94.8% for 12 h. In addition, the electrical property of this hydrogel can recover quickly and the bulb re-bright at once when the broken specimen makes contact.…”