Abstract
A membrane was produced from an ABA-type block copolypeptide composed of poly(L-glutamic acid) as outer segments (A) and poly(L-leucine) as the inner (B). The membrane had phase-separated morphology with the poly(L-glutamic acid) embedded in a continuous matrix of the poly(L-leucine). When the membrane was placed between aqueous KCl solutions of differ ent concentrations, KCl permeated through the continuous do mains of the poly(L-glutamic acid) from one surface to the other (membrane channel). KCl diffused more easily in the α-helical state of the poly(L-glutamic acid) chain than in the random-coil state. The membrane spontaneously generated electrical pulses under the concentration gradient of KCl in the absence of any addi tional external current, voltage, or pressure.
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