基于形状记忆海绵的“门控”液体二极管

“Liquid diode”with“gating”based on shape memory sponge

超浸润Janus膜因其独特的单向液体输送能力,被称为“液体二极管”,引起了人们的广泛关注.近年来,赋予Janus膜智能可控性成为一个新的研究热点.然而,相关的报道仍然很少,且限于调节表面浸润性方面,这很难避免一些局限性,如需要恒定外部刺激和特定的水溶液.在此,我们提出了一种通过调节材料的孔结构来智能控制液体在Janus膜上渗透的新策略,并报告了一种由超亲水海绵(SHS)和疏水形状记忆海绵(HSMS)构成的智能Janus海绵(SJS).基于良好的形状记忆效应,HSMS的孔径和厚度可以在压缩/回复状态之间可逆地改变.随着HSMS的变化,水的渗透可以得到巧妙地控制,这体现在只有在HSMS处于压缩状态时,SJS才呈现“液体二极管”的效果,否则将防止液体从两侧渗透.最后,基于SJS的智能可控性,我们模拟了换药场景,展示了其在伤口敷料领域的潜在应用.本工作首次报道了一种形状记忆Janus膜,为控制液体渗透提供了一种新的方法,成功地避免了现有浸润性响应Janus膜存在的缺点.鉴于其良好的可控性,我们相信它在液体智能操纵方面有潜在的应用.

Superwetting Janus membranes with unique ability in unidirectional liquid transportation,known as“liquid diode”,have attracted much attention.Recently,endowing the Janus membranes with smart controllability becomes a new research hotspot.However,related reports are still rare and limited in regulating surface wettability,which can hardly avoid some imperfections such as the necessary constant external stimuli and change of water solution.Herein,we advanced an unprecedented strategy to smartly control the liquid permeation on Janus membrane by regulating the pore structure of the material,and report a smart Janus sponge(SJS)that is constructed from a super-hydrophilic sponge(SHS)and a hydrophobic shape memory sponge(HSMS).The pore size and thickness of the HSMS can be reversibly changed as it is pressed/recovered based on the excellent shape memory effect.With the variation of the HSMS,the water permeation performance can be smartly controlled,which is embodied in that only when the HSMS is in the pressed state,SJS acts as a“liquid diode”,otherwise it can prevent liquid from penetrating on either side.Finally,based on the smart controllability of the SJS,we simulated the scene of drug administration and demonstrated its potential application in the field of wound dressing.This work firstly reports a shape memory Janus membrane and provides a new way to control the liquid permeation,which can successfully avoid those shortcomings existing in current wetting-responsive Janus membranes.Given its excellent controllability,we believe it has potential applications in intelligent manipulation of liquid.