Preparation And Application Of Highly Adhesive Light-transmissive Superhydrophobic PMMA-PS Films

Water is an integral part of life activities and therefore the precise manipulation and transfer of water is particularly important and holds great industrial and commercial promise.Over the past decades,the preparation of micro and nanostructures has made the precise manipulation and transfer of droplets possible,and has given rise to the rapid development and commercialisation of microfluidic devices.However,droplet transfer in microfluidic devices relies on the use of superhydrophobic and hydrophilic surfaces with a lotus leaf effect in conjunction with each other,which results in contamination and loss during droplet transfer.Achieving droplet directional transfer is the key to reducing contamination,while highly adherent surfaces are the key to achieving the droplet directional transfer process.As the study of wettability progresses,superhydrophobic surfaces can be divided into those with high adhesion and those with low adhesion,of which the inspiration for those with high adhesion comes from rose petals.The rose petal effect is a phenomenon in which a material remains highly adhesive in its hydrophobic state,which can be a good solution to the problem of droplet transfer.However,according to current research,the realisation of an ideal highly adhesive superhydrophobic surface is still challenging and the transfer direction of droplets between two superhydrophobic surfaces has not yet been demonstrated,nor has the characterisation of adhesion.The success of rosepetal effect surface preparation represents a key step towards achieving multi-step manipulation and handling of liquid droplets.Therefore,determining the key properties on which a perfect rose-petal effect state is based has a large commercial and scientific impact.Among routes with tunable micro-and nanostructures,electrostatic spinning is a versatile and cost-effective method and enables the preparation of a wide range of micro-and nanostructures,multiple properties,and flexible materials.In this paper we present a room temperature,non-reactive,simple,controlled,cost effective and scalable method for the one-step synthesis of transparent rose petal bionic coatings for droplet manipulation and droplet transfer.Based on the rose petal theoretical model,we selected the material for which the rose petal effect was most readily observed by relating the actual contact angle to the intrinsic contact angle.The materials in each were prepared by electrostatic spinning,thus allowing the realisation of high performance micro-nanomesh morphologies with highly adhesive hydrophobic wettability.These flexible nanomesh morphologies allow static contact angles from 120°to over 160°,as well as contact angle hysteresis effects from 40° to 80°,a maximum suspended droplet volume of 16 μL,an adhesion force of 127.14 μN and full light transmission of the films.The effect of droplet orientation transfer between hydrophobic films is also analysed and described.The films have good adhesion and are able to trap water.Due to the ability of the prepared films to perform droplet orientation transfer and to be applied on a variety of planes,the applications range from flexible portable wearable biosensors to microfluidics.