Professor Shui Lingling's research group of South China Normal University has made a breakthrough in the field of building multi-layer micro nano structure materials with cross dimensions

Recently, Professor Shui Lingling's research group of South China Normal University has made a breakthrough in the field of using droplet microfluidic technology to construct multi-layer micro nanostructure materials The results are published on the international academic journal ACS Nano, SCI impact factor 13.709, titled "microfluidics assisted fabric of three tier hierarchical microparts for constructing bioinpiped surfaces"（ Doi: 10.1021/acsnano.9b00245, figure 1) Wang Juan, a doctoral student under the guidance of Shui Lingling, is the only first author of the paper, Shui Lingling is an independent correspondent, South China Normal University is the first unit, and Twente University in the Netherlands is the second unit (Figure 1) Wang Juan is a Ph.D candidate in "lots", South China Normal University She was jointly trained by South China Normal University and the University of Twente in the Netherlands Her co tutor is Professor Jan C t eijkel of the University of Twente Fig 1 The published information of the paper (source: ACS Nano) microfluidic technology combines the limited effect of micro nano structure on materials Through the interaction between hydrodynamics and multiphase fluids, materials with different properties can be effectively combined to build multi-dimensional and multi-level structure material units The work of this paper includes: (1) through the droplet microfluidic technology platform, the nanoparticles (100 nanometer scale) are dispersed in the internal phase water, and the uniform micro droplets (10 micron scale) are formed by shearing the external phase (the fluid which is insoluble in the internal phase) at the entrance with flow focusing structure (2) After particle diffusion and self-assembly, the fluid material in the water drop is solidified to form microsphere material (3) Through the chemical reaction between the surface of nanoparticles and polymer materials in the photopolymerization process, controllable nano fold (ten nanometer scale) structure is formed on the surface of nanoparticles (Fig 2, left) In this method, microsphere materials with the size of tens of microns are constructed The microsphere contains hundreds of nanoparticles tightly arranged by self-assembly, and the surface of the particles is covered by folds of tens of nanometers The size of microspheres is controlled by the channel size and fluid flow rate in the process of droplet formation, nanoparticles are controlled by the synthesis process, and wrinkles are controlled by the polymerization process and materials Fig 2 Process schematic diagram and experimental results diagram of three scales of multi-layer structure micro nano materials constructed by droplet microfluidics technology (source: ACS Nano) This multi-layer structure and hydrophobic surface structure unit in nature Very similar, therefore, it can be considered as the wettability principle of materials with special surface wettability, such as rose like surface and gecko toe, by self-assembly arrangement of micro units (Figure 2, right) In this work, the droplet microfluidic technology platform is used for the first time to prepare structural units that can be used to construct special wetted surface materials This method can continuously prepare microsphere materials with controllable size and uniform particle size The performance of materials can be controlled by combining physical structure and chemical materials It is a material processing method with reliable technology, stable performance and continuous production Figure 3 Special wettability surface structure and wettability display results (source: ACS Nano) constructed with prepared multilayer microsphere materials