Heat-induced voltage generation in hexadecyl merocyanine dye-probed planar lipid membranes

Abstract

A hexadecyl merocyanine dye was used as a heat driven proton gate, by incorporating it in a planar lipid membrane which is a good model for biological membranes. Being hydrophobic in nature, it prevents charge recombination, and transmembrane voltages of high magnitude (∼310 mV) were obtained upon heating. The process was reversible and the whole cycle took about 20 h, suggesting that the system could be used as a heat driven storage cell. Comparison of the X-ray diffraction patterns of the thin films of the dye at 30°C showed a heat-induced conformational change in the crystalline structure of the dye. From differential thermal analysis three reversible phase transitions were observed, at 39·2°C, 53·7°C and 62·1°C, and the associated enthalpy changes were calculated. The results indicate that the heat-induced conformational change of the dye molecule is responsible for the observed thermovoltage generation.