構造変化を伴うミリポアＤＯＰＨ膜の膜電気抵抗振動

Abstract

A Millipore DOPH model membrane is composed of a Millipore filter whose pores are filled with dioleylphosphate (DOPH);and increases its electric resistance by a factor of 104 when Ca2+ ions are combined with it. The concentration of CaCl2 which increases the membrane resistance depends on the density of DOPH adsorbed in the filter and the initial KCl concentration. The surface structure of the membrane changes at the same time when the membrane resistance increases. By the stereoscopic microscope mounted a photomultiplier on the eyepiece the structure change can be detected quantitatively as an intensity change of reflected light, i. e.; Ca2+ ions decrease the intensity to 50% as compared with the original hydrophilic state.The membrane resistance which became higher with Ca2++ ions oscillates while the current and pressure stimuli are applied to the membrane. The frequency is dependent of these stimuli. These stimuli change the membrane surface structure to make locally the hydrophilic areas. It is conceivable that the structure changes are caused by replacing Ca2+ ions with K+ ions in the hydrophilic groups of DOPH molecules.