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Polymeric coatings are commonly employed to alter surface properties. While some coatings are designed to remain stable over a prolonged period, in applications such as pharmaceuticals or fertilizers, the coating is designed to erode and reveal or release the underlying material. Self-immolative polymers (SIPs) undergo depolymerization following the cleavage of stimuli-responsive end-caps from their termini, enabling controlled depolymerization in the solid state and in solution. Poly(ethyl glyoxylate) (PEtG) is a promising SIP because of its depolymerization to benign products, but its amorphous structure and low glass-transition temperature make it unsuitable alone for coating applications. This study explored the blending of PEtG with polyesters including polycaprolactone (PCL), poly( l -lactic acid), and poly( R -3-hydroxybutyrate). Block copolymers of PEtG with PCL were also synthesized and studied. It was found that the phase separation behavior and consequently the thermal and mechanical properties of the materials could be tuned according to the composition of the blend, while the stimuli-responsive degradation of PEtG was retained in the blends. This work therefore provides a framework for the application of PEtG-based coatings in applications ranging from pharmaceuticals to agricultural products.

Robotics is a frontal interdisciplinary subject across the fields of mechanical engineering, chemical and materials engineering, artificial intelligence, and nanotechnology. Robotic devices with a variety of frameworks, functionalities, and actuation modes have been developed and employed in the manufacture of advanced materials and devices with improved efficiency and automation. In recent years, soft robots have attracted a significant amount of interest among scientific researchers and technological engineers because they can offer the desired safety, adaptability, sensibility, and dexterity that conventional robotics cannot deliver. To date, emulating living creatures in nature has been a promising approach to design soft robots. For living creatures, both body deformation and their surface characteristic are essential for them to function in dynamic ecological environments. Body deformation offers athletic ability while surface characteristics provide extraordinary adaptable interactions with the environment. In this article, we discuss the recent progress of emulating the body deformation of living creatures such as shrinking/expanding, bending, and twisting and programmable deformations based on the manipulation of shape-changing behaviors of liquid-crystal polymeric materials (LCPs) and the interfacial technologies to build up various microstructures similar to the interface of living creatures. We further review the pioneering work that integrates interfacial engineering and the shape-changing modulation of LCPs to develop biomimetic soft robotic devices. We also provide an outlook for opportunities and challenges in the design and fabrication of advanced biomimetic soft robots based on the synergetic combination of interfacial engineering and shape-changing modulation.

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