The convergence of carbon nanomaterials and functional polymers has led to the emergence of smart carbon–polymer nanocomposites (CPNCs), which possess exceptional potential for next-generation sensing and actuation systems. These hybrid materials exhibit unique combinations of electrical, thermal, and mechanical properties, along with tunable responsiveness to external stimuli such as strain, pressure, temperature, light, and chemical environments. This review provides a comprehensive overview of recent advances in the design and synthesis of CPNCs, focusing on their application in multifunctional sensors and actuator technologies. Key carbon nanomaterials including graphene, carbon nanotubes (CNTs), and MXenes were examined in the context of their integration into polymer matrices to enhance performance parameters such as sensitivity, flexibility, response time, and durability. The review also highlights novel fabrication techniques, such as 3D printing, self-assembly, and in situ polymerization, that are driving innovation in device architectures. Applications in wearable electronics, soft robotics, biomedical diagnostics, and environmental monitoring are discussed to illustrate the transformative impact of CPNCs. Finally, this review addresses current challenges and outlines future research directions toward scalable manufacturing, environmental stability, and multifunctional integration for the real-world deployment of smart sensing and actuation systems.

Effective heat dissipation is crucial for the optimal performance and safety of electronic devices. Electronic products and energy-efficient home equipment generate more heat during operation and continuous use. Therefore, it is essential to implement efficient heat dissipation methods to prevent problems such as component malfunctions, increased failure rates, and safety hazards. Polymer composites have recently garnered attention due to their unique properties and versatility. These composites achieve improved thermal conductivity by incorporating ceramic nanoparticles, making them suitable for heat dissipation applications. However, challenges arise from the electrical conductivity of ceramic fillers, which can interfere with the performance of precision electronic components. Additionally, the thermal conductivity of ceramic nanoparticles is typically low (less than 10 W/(m·K)), requiring high filler content (above 50 vol.%), which increases the cost and weight of the composite materials. Nanofiber-based heat dissipation sheets, particularly those fabricated through electrospinning, offer a promising alternative. Ceramic nanofibers provide continuous thermal pathways within the polymer matrix, enhancing heat conduction. However, while in-plane thermal conductivity can be significantly improved, the thermal conductivity in the thickness direction remains limited due to the insufficient heat conduction network in this direction. Advanced techniques such as freeze-drying offer promising solutions to this problem, enabling the formation of three-dimensional (3D) interconnected nanofiber networks. These 3D structures demonstrate superior performance over conventional one-dimensional nanofibers. This review provides a comprehensive overview of the synthesis and integration of ceramic nanofibers, including aluminum oxide (Al ₂ O ₃ ), aluminium nitride (AlN), silicon dioxide (SiO ₂ ), titanium dioxide (TiO ₂ ), and beryllium oxide (BeO), into polymer matrices for heat dissipation applications. It discusses the thermal and electrical performance of these materials alongside emerging strategies to optimize thermal conductivity in both in-plane and thickness directions. Furthermore, this review highlights recent advances in freeze-drying techniques for fabricating 3D nanofiber structures and outlines future directions for overcoming the challenges in synthesizing high-performance ceramic nanofibers.

Nanocomposite (NC) hydrogel (HG) sensors have emerged as a transformative innovation in wearable healthcare monitoring systems. By incorporating carbon-based, metal-based, and polymer-based NCs, these sensors offer exceptional properties such as biocompatibility, flexibility, high water content, and stretchability—making them highly suitable for continuous, real-time physiological monitoring. Advanced fabrication techniques, including in situ polymerization, conformal coating, and dynamic crosslinking, significantly enhance their functional performance and scalability for practical deployment. The mechanical robustness and electrical responsiveness of these NC HGs, coupled with self-healing capabilities, strong adhesion to skin, and resistance to environmental stressors, ensure their reliability and durability in diverse healthcare applications. These HG sensors have shown great promise in monitoring vital signs, managing chronic conditions, supporting rehabilitation, enabling real-time glucose monitoring, and facilitating wound healing. Despite their considerable potential, several challenges remain—particularly in technical optimization, user comfort and integration, and regulatory approval—that must be addressed to enable their widespread adoption. This review highlights recent innovations, material properties, and healthcare applications of NC HG sensors and discusses the critical challenges that must be overcome to fully realize their impact as wearable textile materials in modern healthcare systems.