PHOTOFLEXOELECTRIC EFFECTS IN BILAYER-LIPID MEMBRANES

Cadmium sulfide (CdS) nanocrystalline particulate Films were generated , in situ, on one side of glycerol monooleate (GMO) bilayer lipid memb ranes (BLMs). The CdS growth on the GMO BLMs was followed by optical m icroscopy. Curvature-induced polarization (flexoelectricity) of GMO BL Ms, in the absence and in the presence of CdS nanocrystalline particul ate films, was investigated in the dark and under bandgap illumination . Flexoelectric responses were elicited by oscillating acoustic pressu re, in the 100-1000 Hz frequency range, applied onto the side of the G MO BLM which did not contain CdS. Electric currents, generated under a voltage clamp, and membrane potentials, generated under a current cla mp, were measured. GMO BLMs, in the absence of CdS, gave photoindepend ent flexoelectric responses. On the other hand, flexoelectric response s of GMO BLMs, decorated by CdS, changed upon illumination. Photoflexo electric responses were observed to vary as a function of the amount o f CdS deposited onto the GMO BLM. The obtained results were rationaliz ed in terms of modulation of the illumination-generated photovoltage b y the oscillating BLM.