Hydrophilic Sponges for Leaf-Inspired Continuous Pumping of Liquids.

Tingjiao Zhou,Zhou Liu,Jieyao Zheng,Junmin Zhang,Chuanxin He,Deyong Zhu,Stephan Handschuh-Wang,Xuechang Zhou,Yizhen Liu,Xiaohu Zhou,Jinbin Yang

doi:10.1002/advs.201700028

Abstract

A bio‐inspired, leaf‐like pumping strategy by mimicking the transpiration process through leaves is developed for autonomous and continuous liquid transport enabled by durable hydrophilic sponges. Without any external power sources, flows are continuously generated ascribed to the combination of capillary wicking and evaporation of water. To validate this method, durable hydrophilic polydimethylsiloxane sponges modified with polyvinyl alcohol via a “dip‐coat‐dry” method have been fabricated, which maintains hydrophilicity more than 2 months. The as‐made sponges are further applied to achieve stable laminar flow patterns, chemical gradients, and “stop‐flow” manipulation of the flow in microfluidic devices. More importantly, the ease‐of‐operation and excellent pumping capacity have also been verified with over 24 h's pumping and quasi‐stable high flow rates up to 15 µL min−1. The present strategy can be easily integrated to other miniaturized systems requiring pressure‐driven flow and should have potential applications, such as cell culture, micromixing, and continuous flow reaction.

Highlights

A bio-inspired, leaf-like pumping strategy by mimicking the transpiration large oak tree transpires totally ≈151 kL year−1
Smart methods for controlled liquid transport systems, possessing the features of ease-of-operation, portability, and robust and excellent performance, are needed to expand their application scope. To further advance this field, we developed a strategy that combines the capillary action and evaporation of water to mimic the continuous pumping in biosystem
“Dip-coat-dry” modification of the PDMS sponge surface using polyvinyl alcohol (PVA) was carried out to attain long-term hydrophilicity for water wicking by capillary action

Summary

Introduction

A bio-inspired, leaf-like pumping strategy by mimicking the transpiration large oak tree transpires totally ≈151 kL year−1. To achieve such leaf-like continuous pumping of water, the system requires a long-term hydrophilic modification of surfaces and 3D-interconnected porous structures.

Results

Conclusion