Layered Titanium Carbide‐Mediated Fast Shape Switching and Excellent Thermal and Electrical Transport in Shape‐Memory‐Polymer Composites for Smart Technologies: MAX Versus MXene

Abstract

Stimuli‐responsive materials can frequently tune between their temporary and original shapes, and have the potential for artificial intelligence‐based technologies in robotics, aerospace, biomedical, engineering, security, etc. Shape memory polymers (SMPs) are promising for these technologies but their inadequate thermal and electrical characteristics causing slow shape recovery limit their practical applications. Herein, for the first time, comprehensively and precisely the shape memory polyurethane (PU), a promising SMP, via a variety of novel layered titanium carbides fillers, namely, Ti2AlC (MAX1), Ti3AlC2 (MAX2), and Ti3C2 (MXene), is engineered. The resultant PU‐composites show 30–50% faster shape recovery in different environments, 20–25% greater extent of shape recovery in the load‐constrained environment, 100–125% higher thermal conductivity, and 700–16 000× higher electrical current. Importantly, the reinforcement of even a small amount of MAX and MXene (such as 0.25 wt%) has largely boosted the performance of PU. Considering ease of processability and performance enhancement factors, the MAX‐phase fillers may be preferred over MXene‐phase fillers for next‐generation composites development. Employing PU composite component as both heat‐sensor and actuator, a unique heat detector/fire alarm device that works successfully in simulated heat and fire environments is demonstrated. This work is crucial for enabling futuristic technologies.