Research On Multifunctional Magnetically Responsive Biomimetic Surfaces Fabricated By Femtosecond Laser And Their Applications In Microfluidic Manipulation

Water and air are essential resources for the survival of both animals and plants.Due to the uneven distribution of water and air in nature,many organisms have evolved unique abilities to manipulate and collect water and air for their survival.These organisms often possess unique micro-and nanostructured surfaces that enable spontaneous transport of common microfluids such as water droplets and bubbles.Inspired by the unique micro-and nanostructures found in biological surfaces,researchers have developed numerous artificial micro-and nanostructured functional surfaces for microfluidic transport,advancing research and applications in areas such as water mist collection,agricultural irrigation,and wastewater treatment.With the development of society and advancement of technology,the application scope of microfluidic transport is expanding,demanding higher performance in transportation and manipulation.Achieving more efficient,flexible,and universal microfluidic control remains a critical challenge.In contrast to spontaneous fluid transport observed in biological surfaces,the introduction of external stimuli-responsive artificial surfaces ofers customizable and flexible solutions to address the aforementioned challenges and requirements in the field.This study addresses the existing challenges in microfluidic control by combining femtosecond laser micro-nano fabrication technology with magneto stimulation techniques,resulting in several multifunctional magnetoresponsive biomimetic surfaces.The main focus of the study includes:1.A novel isotropic biomimetic magnetic-controlled superlubricated surface(FLAMS)was fabricated using femtosecond laser technology,enabling ultrafast underwater bubble transport in any direction.By manipulating the magnetic fluid curvature on the FLAMS surface using a magnetic field,the capture and propulsion of bubbles were achieved,demonstrating various high-performance bubble manipulation behaviors and applications.This research provides a new approach and method for intelligent and efficient control of underwater bubbles.2.A novel magnetic-controlled superlubricated track with anisotropic droplet sliding,termed Femtosecond Laser-Induced Anisotropic Track(FOTs),was obtained using femtosecond laser technology.The anisotropic sliding behavior of underwater bubbles on the FOTs surface in two orthogonal directions was systematically investigated,elucidating the underlying fluid dynamic mechanisms.Additionally,two applications,bubble screening and bubble-assisted remote optical shutter,were demonstrated.This work provides a method for droplet manipulation on highperformance anisotropic functional surfaces and enriches the theoretical research on the sliding dynamics of bubbles on superlubricated surfaces.3.A biomimetic magnetoresponsive composite microstructure,termed Gradient Magnetism-Responsive Micropillar/Microplate Arrays(GMRMA),was fabricated using a combination of femtosecond laser and soft lithography techniques.By manipulating the rapid asymmetric deformation of different biomimetic microstructures using a magnetic field,real-time,fast,and in-situ reversible switching between isotropic and anisotropic rolling states of droplets was achieved.Based on the GMRMA surface,droplet classification and screening of different types of droplets were achieved.This study provides a novel method for on-demand control of droplet rolling states,holding promising prospects in the fields of microfluidics and microchemical reactions.