Changchun Yu1 Xuanbo Zhu2 Caiyun Wang1 Yahong Zhou2 Xiaoteng Jia1 Lei Jiang2 Xiao Liu1 Gordon Wallace1

1, Intelligent Polymer Research Institute, Wollongong, New South Wales, Australia
2, CAS Key Laboratory of Bio-inspired Materials and Interfacial Science Technical Institute of Physics and Chemistry, Beijing, , China

Inspired by the cell membranes which can precisely control the ion flow, the artificial analogs are developed to reproduce biological energy conversion process. Using biomimetic smart nanopores to convert osmotic energy into electricity have been widely investigated. They are commonly composed of two different materials and require the complicated fabrication technique. The use of a single component macroporous conducting membrane to harvest the osmotic energy has not been reported.
Here, we developed a macroporous free-standing polypyrrole film with two types of pores via a straightforward chemical synthesis method. This flexible asymmetric macroporous membrane is conductive (~200 S/m). It could generate a voltage in the range of several to around 200 mV, reaching 207 mV when the gradient ratio was 106. The power density harvested from a gradient using artificial seawater (0.5 M NaCl) and river water (0.01M NaCl) reached 0.087 W/m2 with an external resistor of 5 KΩ. Impressively, its ionic conductance can be tuned by the applied potential. This PPy film has also been demonstrated to be a good substrate for Adipose-derived stem cell adhesion and proliferation. With its unique property of electrical and ionic conductivity, this biocompatible PPy membrane shows its promising application in the bioelectrogenesis and clean energy conversion field.