Direct Laser Writing Of Superhydrophobic PDMS Elastomers For Controllable Manipulation Via Marangoni Effect

The energy problem is attracting more and more attention all over the world.The problem caused by energy shortage is coming.For example,how to actuate the actuator with less or no non-renewable energy.These problems have attracted the attention of many scholars,driven by these problems,self-driven actuators came into being.The so-called self-driven actuator is the actuator itself to obtain energy from the outside world,to convert into their own energy and to be actuated.While the external energy including solar energy,wind energy,etc.Among them,light energy because of its easy to get,safe,green and environmental advantages are particularly important.Actuators that use light energy as a driving energy source are called light-driven actuators.The operation principle of the light-driven actuator can be divided into the photochemical effect,photo-thermal effect,photoelectric conversion and so on.Because of the obvious phenomenon of photo-thermal conversion method,it has been widely researched by researchers.It is found that it can convert light energy into thermal energy,and the thermal energy can cause some changes such as thermal expansion,surface tension caused by heat transfer,etc.,so that the actuator generates different motions,etc.Direct conversion of light energy into kinetic energy of the remote operation mode has the advantages of non-contact,controllable and continuous.Although many pioneering work has demonstrated controllability of the device by creating a thermal gradient profile through illumination that further causes a surface tension gradient to be controlled.However,the problem still exists,such as,firstly how the materials of light-to-heat conversion and device substrates for efficient simple and flexible combination.The second is how to design a clever structure to achieve a variety of functions.Third,when the device is moving on the surface of the liquid,the viscosity of the surface of the fluid generates resistance,which will seriously hinder the movement of the actuator.How to reduce these resistances is an urgent problem to be solved.These problems have seriously hindered the development of self-driving actuator steps.This article focuses on some problems in the above mentioned and studied.A simple one-step processing method is mainly studied to fabricate a floating device that can be actuated by light.This floatable device has a versatile surface that both absorbs light and reduces the drag caused by water viscosity.In this work,we use the direct laser writing technology can not only direct write asymmetric patterns,but also for surface modification.Three kinds of typical light-driven actuators can be prepared by integrating a multi-functional surface at a specific location or designing an asymmetrical structure.These three devices can rapidly perform linear or rotational movement under the illumination of a light source.Even more surprising is that these devices can not only use the traditional light source that is laser,also can use focused sunlight and a wide range of incandescent lamps to drive.Our approach provides a simple,effective method for fabricating fast-moving floating devices and low-power light-driven actuators.