Tailoring Carbon Nanotube Density for Modulating Electro-to-Heat Conversion in Phase Change Composites

• Published in: Nano letters Vol. 13; no. 9; pp. 4028 - 4035
• Main Authors: Liu, Zhenpu, Zou, Ruqiang, Lin, Zhiqiang, Gui, Xuchun, Chen, Renjie, Lin, Jianhua, Shang, Yuanyuan, Cao, Anyuan
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 11-09-2013
• Subjects: Arrays; Condensed matter: structure, mechanical and thermal properties; Construction; Conversion; Cross-disciplinary physics: materials science; rheology; Density; Electric potential; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Materials science; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Nanotubes; Phase change; Physics; Specific phase transitions; Structural transitions in nanoscale materials; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Voltage; thermal energy storage; nanocomposite; Phase change material; carbon nanotube array; Encapsulation; Phase transformations; Porous materials; Carbon nanotubes; Modulated structure; Crystallinity; Dispersions; Nanostructures; Manufacturing processes; Composite materials; Nanocomposites; Polymers; Arrays; Nanostructured materials
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl401097d

We report a carbon nanotube array-encapsulated phase change composite in which the nanotube distribution (or areal density) could be tailored by uniaxial compression. The n-eicosane (C20) was infiltrated into the porous array to make a highly conductive nanocomposite while maintaining the nanotube dispersion and connection among the matrix with controlled nanotube areal density determined by the compressive strains along the lateral direction. The resulting electrically conductive composites can store heat at driven voltages as low as 1 V at fast speed with high electro-to-heat conversion efficiencies. Increasing the nanotube density is shown to significantly improve the polymer crystallinity and reduce the voltage for inducing the phase change process. Our results indicate that well-organized nanostructures such as the nanotube array are promising candidates to build high-performance phase change composites with simplified manufacturing process and modulated structure and properties.