Shape Memorable and Self-Healable Smart Hydrogels and Emerging Directions

Hydrogels have emerged as one of the most versatile materials with fascinating applications in sensing, soft robotics, energy storage, and biomedicine. To match the pace of rapid advancement, the development of intelligent hydrogels that are able to sense, respond to, and adapt exactly to the stimulus, hence exploiting their full potential for use in sophisticated and dynamic applications have been started lately. Researchers are keen to incorporate shape memory and self-healing properties. Shape memory hydrogels (SMHs) are intelligent hydrogels that rely on a shape memory polymer matrix and are sensitive to external stimuli such as temperature, light, and pH, and they are able to change their properties based on the external stimulus. SMHs are sensitive to self-healing through chemical and physical bonds, and they are able to heal themselves upon being damaged. SMHs can be deformed largely and revert to their former state based on an external stimulus. This review comprehensively covers the basic mechanisms, properties, and various applications of SMHs. An effort is made to explore the inclusion of AI and ML within SMH systems, pointing out their recent roles and potential benefits, with new opportunities. Besides, this review covers the current challenges for SMHs and presents prospects for future studies on their development.