Smart Droplets And Ion Transport Regulation And Applications Based On Responsive Layered Two-dimensional Material

There are many types of material cycles in living organisms,including but not limited to food intake,internal and external exchange of carbon dioxide and oxygen,water absorption and collection processes,and ion transport between cells.Research has found that organisms have evolved over millions of years to complete these material transfer processes,forming system functions that are far more precise and energy-efficient than modern human machines.By observing the phenomenon of water transport in organisms,researchers have developed a series of intelligent droplet transport technologies,which have important applications in fields such as microfluidics,medical diagnosis,and drought water harvesting.For the ion transport of biological cells,researchers found that electric eels can use the ion channels on the plasma membrane of electric cells to carry out ion selective transport,and generate transient action potential up to 600 V.In addition,certain cell membranes in the human body have specific ion channels that recognize a single cation.Inspired by the above phenomenon,researchers have developed intelligent ion transmission channels,and then designed a series of ion screening collection and osmotic energy conversion power generation materials,making significant contributions to the collection of trace element and the development of new energy sources.In recent years,layered two-dimensional materials have shown enormous application potential in the field of material transport due to their advantages of easy preparation,easy assembly into macroscopic membrane materials,and uniform and continuous nanoscale channel sizes.Many layered two-dimensional materials have unique intrinsic stimulus responses such as light,electricity,and heat,which also provide the possibility for intelligent material transport regulation.In this paper,layered two-dimensional materials are applied to the field of droplet transport and ion transport,and photothermal SLIPS(slippery liquid-infused porous surfaces)microtubule channels for intelligent droplet transport and layered two-dimensional material films for intelligent ion transport are developed,which are respectively used for droplet microfluidics,salt differential energy power generation and ion screening.The main research results are as follows:1.The superlubricity microtubule channel based on the photothermal response MXene is used for the controllable transmission of droplets.This photothermal microtube channel is prepared based on the most widely used material in microfluidic devices,polydimethylsiloxane(PDMS).At the bottom of the microtubule channel,MXene nanosheets were compounded with PDMS to endow the bottom with photothermal characteristics,and the inner wall of the SLIPS microtubule channel was prepared.Through this microtubule structure,light can be transmitted through the transparent upper part to the inner surface of the bottom of the microtubule,allowing MXene nanosheets to absorb light energy,generate temperature gradients through the photothermal effect,and induce the generation of wetting gradients,successfully driving various liquids such as water droplets,oil droplets,milk,ethylene glycol,etc.In addition,the SLIPS surface reduces the contact angle hysteresis and viscous resistance,so the driving can occur at relatively low temperatures,avoiding the biocompatibility problem at high temperatures.Our method also avoids material fatigue problems caused by frequent physical deformation of pipelines in previous studies,and has stronger stability.The research of this project provides new materials and strategies for intelligent droplet transfer,as well as new ideas for simplifying microfluidic systems.2.A highly selective Na+channel based on two-dimensional vermiculite layered membrane is used for wastewater based salt differential power generation.Vermiculite nanosheets were obtained by ion exchange method and layered membranes were prepared through vacuum filtration.The layered membrane utilizes the unique narrow interlayer spacing and negative surface charge of vermiculite nanosheets to achieve rapid transport of monovalent cations such as Na+,as well as efficient removal of divalent cations such as Cu2+,Mn2+,Pb2+,and has a high screening ratio.Through testing in a simulated wastewater/seawater system,efficient salinity gradient power generation based on wastewater has been achieved,effectively blocking the infiltration of heavy metal ions and secondary pollution in wastewater.This study proposes a new method for an integrated platform for simultaneous power generation and wastewater purification,and provides a new strategy for material development of multifunctional systems based on nanofluids.3.A composite layered membrane based on MXene/Gibbsite is used for photoinduced ion transport and salt difference power generation.Photoresponsive ion transport composite films were prepared using two materials,MXene and Gibbsite.Introducing positively charged Gibbsite into negatively charged MXene can effectively regulate the interlayer spacing of the composite film through electrostatic interaction between the two.Based on the excellent photothermal effect of MXene,the photoresponsive ion directed transport of monovalent cations such as Na+and K+is achieved.And through testing on an artificial river/seawater system,efficient salinity gradient power generation has been achieved.