Thermometric carbon composites

Abstract

A composition of electrically conductive composites for temperature sensing comprises conductive particles. The composite forms from a suspension. The suspension comprises the particles and solvent, and the particles are conductive particles with aspect ratio larger than one. The conductive composite retains a negative temperature coefficient when in contact with certain specific surfaces. The particles within the composite self align.

1 . A conductive carbon composite material comprising of a cylindrical form of conductive carbon with an aspect ratio larger than one and a planar form of conductive carbon with an aspect ratio larger than one, the two forms of conductive carbon dispersed in one another in the mass ratio from 1:100 to 100: and preferably in a mass ratio close to 1:1 and supported by a compatible substrate. The compatible substrates are surfaces of aliphatic hydrocarbons, polyolefins, alcohols and polyols, cellulose 
     
     
         2 . (canceled) 
     
     
         2 . The formula of  claim 1 , wherein average planar particles diameter is of the order of the average length of the tubular particles. 
     
     
         3 . The formula of  claim 1 , wherein the tubular and planar conductive particles are in any ratio in the composite material. 
     
     
         4 . The formula of  claim 2 , wherein the total area of the planar particles is of the same order of magnitude as the product of the number of tubular particles present and of the area established by the mean square radius of gyration of the tubular particles. 
     
     
         5 . The formula of  claim 3 , wherein planar particles are graphite and tubular particles are carbon nanotubes. 
     
     
         6 . The formula of  claim 3 , wherein tubular particles comprise single wall carbon nanotubes. 
     
     
         7 . The formula of  claim 3 , wherein tubular particles comprise multiple wall carbon nanotubes. 
     
     
         8 . The formula of  claim 3 , wherein the composite material further comprises a binder. 
     
     
         9 . The formula of  claim 3 , wherein planar particles are selected from the group that consists of metals and conductive polymers and tubular particles are carbon nanotubes. 
     
     
         10 . The formula of  claim 9 , wherein tubular particles comprise single wall carbon nanotubes. 
     
     
         11 . The formula of  claim 9 , wherein tubular particles comprise multiple wall carbon nanotubes. 
     
     
         12 . The formula of  claim 9 , wherein the composite material further comprises a binder, 
     
     
         13 . The formula of  claim 9  wherein tubular particles are selected from the group consisting of semiconductors and conductive polymers. 
     
     
         14 . The formula of  claim 13 , wherein the ink further comprises a binder. 
     
     
         15 . The formula of  claim 3  can be connected by two conductors. 
     
     
         16 . The resistance decreases with increasing temperature for the two terminal device of  claim 15 . 
     
     
         17 . The anisotropic particles of formula of  claim 3  are oriented with respect to each other in the ink matrix. 
     
     
         18 . The orientation of the anisotropic particles of formula of  claim 3  occurs at deposition without external motivation or processing, 
     
     
         19 . The ratio of particles in  claim 1  affects the temperature sensitivity of the two terminal device in  claim 15 . 
     
     
         20 . Increasing the ratio of tubular to planar particles in  claim 1  above a ratio of 1:1 decreases the temperature sensitivity of the two terminal device in  claim 15 .