title: Reversible temperature regulation of electrical and thermal conductivity using liquid-solid phase transitions.
abstract: Reversible temperature tuning of electrical and thermal conductivities of materials is of interest for many applications, including seasonal regulation of building temperature, thermal storage and sensors. Here we introduce a general strategy to achieve large contrasts in electrical and thermal conductivities using first-order phase transitions in percolated composite materials. Internal stress generated during a phase transition modulates the electrical and thermal contact resistances, leading to large contrasts in the electrical and thermal conductivities at the phase transition temperature. With graphite/hexadecane suspensions, the electrical conductivity changes 2 orders of magnitude and the thermal conductivity varies up to 3.2 times near 18 °C. The generality of the approach is also demonstrated in other materials such as graphite/water and carbon nanotube/hexadecane suspensions.
authors.affiliation: Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
authors.forename: Ruiting
authors.initials: R
authors.lastname: Zheng
authors.forename: Jinwei
authors.initials: J
authors.lastname: Gao
authors.forename: Jianjian
authors.initials: J
authors.lastname: Wang
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
mesh_terms: D000473:Alkanes / Q000737:chemistry; D004553:Electric Conductivity; D006108:Graphite / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D008962:Models, Theoretical; D043942:Nanotubes / Q000737:chemistry / Q000648:ultrastructure; D044367:Phase Transition; D013696:Temperature; D013814:Thermal Conductivity; D014465:Ultrasonics
chemical_list: D000473:Alkanes; D006108:Graphite; C007932:n-hexadecane