PYROELECTRIC BEHAVIOR OF POLYVINYL-ALCOHOL (PVA)-POLYVINYL PYRROLIDONE (PVP) POLYMER BLEND FILMS

The pyroelectric behaviour of PVP-PVA polyblend films of different wei ght ratios, grown by the isothermal immersion technique has been studi ed under different polarizing fields and temperatures in a vacuum of 1 0(-3) Torr. The pyroelectric coefficient g(3) is evaluated from the me asured pyroelectric current. The pyroelectric behaviour of the blend s howed a systematic variation with the ratio of the constituents, i.e. the pyroelectric coefficient was found to increase with increasing per centage of PVP in the blend suggesting good miscibility of the individ ual polymers in the blend. The effect of electrode materials of differ ent work functions on the pyroelectricity was also studied. The observ ed pyroelectricity in the polymer blend films was considered to be due to both dipolar orientation and space charge polarization. Compared t o other blend compositions, polymer blend I (PVP: PVA=75:25) was sugge sted as the best electret having better pyroelectric properties.