THE USE OF THIN-FILM THERMOCOUPLES TO DETERMINE THE THERMAL-CONDUCTIVITY AND YOUNGS MODULUS OF COATINGS AND INTERFACES

Linear and differential thin film thermocouples, typically 500-1000ang strom thick, were fabricated on flexible polymer and paper substrates by thermal evaporation. Both types of thermocouples had thermal sensit ivities of approximately 4 muV/degrees-C, for temperatures between 20- degrees-C and 40-degrees-C, on the paper and polymer-coated paper subs trates. The transverse thermal conductivity (k(t)), i.e., thermal cond uctivity in the direction perpendicular to the plane of the films, of polyimide (Kapton-H(R)) films, of a clay-coated paper, and of a polyst yrene coating on paper were determined by depositing linear thermocoup les on both sides of the films and raising the temperature of one junc tion and measuring the heat flux and, at equilibrium, the temperature of the other junction. Shear and Young's moduli of the polymer films w ere estimated from the measured thermal conductivity values, assuming the Debye model of thermal conductivity.