Light-Driven Shape-Programmable Vitrimer Nanocomposites with Infrared Stealth Functionality: A Catalyst-Free Strategy via Carboxylated CNT-Embedded Covalent Adaptable Networks

Combining the advantageous properties of both thermoplastics and thermosets, while further extending the functionality through nanofiller incorporation, vitrimer nanocomposites demonstrate a wide range of application scenarios. To fully exploit the potential of vitrimer nanocomposites, a hybridized covalent adaptable network (CAN) embedded with carboxylated carbon nanotubes (CNTs) was constructed via a facile one-pot method. The prepared vitrimer nanocomposite exhibits remarkable improvements in performance and functionality: (1) Owing to the catalytic effect of carboxyl groups on CNTs, the vitrimer nanocomposite requires no external catalyst. (2) The synthesis efficiency is enhanced, with the vitrimer nanocomposite forming in just 8 min due to rapid transesterification promoted by the network structure of carboxylated CNTs embedded in the CANs. (3) Carboxyl-modified CNTs exhibit compatibility with the polymer matrix, ensuring uniform dispersion in the system and thereby endowing the vitrimer nanocomposite with improved mechanical performance, dimensional stability, and a high tensile strength of 49.1 MPa, while the 1CNT sample also exhibited the highest creep resistance by maintaining nearly constant strain even after 1000 s. (4) Leveraging the photothermal effect of CNTs embedded in CANs, the vitrimer nanocomposite can be locally heated above its topological freezing temperature, enabling rapid shape-programmability at targeted locations, such as recovering into an “L” shape within 15 s. (5) The strong infrared absorption of CNTs in the long-wavelength range, quantified by a significant rise in the infrared absorption index (from 0.025 to 0.10 with increasing CNT content above 0.3 wt %), reduces infrared transmittance, imparting effective thermal infrared blocking behavior to the vitrimer nanocomposite. Consequently, the CNT-embedded CANs structure significantly enhances both the performance and functionality of the vitrimer nanocomposite.