In JoVE (1)
Articles by Jia Man in JoVE
Fabricating High-viscosity Droplets using Microfluidic Capillary Device with Phase-inversion Co-flow Structure Jiang Li1, Jia Man2, Zhongnan Li2, Haosheng Chen2 1School of Mechanical Engineering, University of Science and Technology Beijing, 2State Key Laboratory of Tribology, Tsinghua University A phase-inversion co-flow device is demonstrated to generate monodisperse high-viscosity droplets above 1 Pas, which is difficult to realize in droplet microfluidics.
Other articles by Jia Man on PubMed
Mass-Transfer-Induced Multistep Phase Separation in Emulsion Droplets: Toward Self-Assembly Multilayered Emulsions and Onionlike Microspheres Langmuir : the ACS Journal of Surfaces and Colloids. Aug, 2016 | Pubmed ID: 27427849 Mass-transfer-induced multistep phase separation was found in emulsion droplets. The agent system consists of a monomer (ethoxylated trimethylolpropane triacrylate, ETPTA), an oligomer (polyethylene glycol diacrylate, PEGDA 700), and water. The PEGDA in the separated layers offered partial miscibility of all the components throughout the multistep phase-separation procedure, which was terminated by the depletion of PEGDA in the outermost layer. The number of separated portions was determined by the initial PEGDA content, and the initial droplet size influenced the mass-transfer process and consequently determined the sizes of the separated layers. The resultant multilayered emulsions were demonstrated to offer an orderly temperature-responsive release of the inner cores. Moreover, the emulsion droplets can be readily solidified into onionlike microspheres by ultraviolet light curing, providing a new strategy in designing particle structures.
Microfluidic Generation of High-Viscosity Droplets by Surface-Controlled Breakup of Segment Flow ACS Applied Materials & Interfaces. Jun, 2017 | Pubmed ID: 28589716 Fluids containing high concentration polymers, sols, nanoparticles, etc., usually have high viscosities, and high-viscosity fluids are difficult to be encapsulated into uniform droplets. Here we report a surface-controlled breakup method to generate droplets directly from various aqueous and nonaqueous fluids with viscosities of 1.0 to 11.9 Pa s and a dispersed-to-continuous viscosity ratio up to 1000, whereas the volume fraction of droplets up to 50% can be achieved. It provides a straightforward method to encapsulate high viscosity fluids, in a well-controlled manner in the rapid developing droplet-based applications, including materials synthesis, drug delivery, cell assay, bioengineering, etc.
Size-Dependent Phase Separation in Emulsion Droplets Chemphyschem : a European Journal of Chemical Physics and Physical Chemistry. Feb, 2018 | Pubmed ID: 29399932 Phase separation occurs in emulsion droplets containing poly (ethylene glycol) diacrylate (PEGDA), glycerol, and ethanol to form a glycerol-in-PEGDA structure, and the phase separation process is found to depend on the droplet size. The mechanism of this size-dependent phase separation is dependent on the droplet sizes changing the phase separation time by changing the evaporation speed of mutual solvent ethanol, and the relationship between the separation time T and the droplet diameter D is derived as T≈D , which has been validated by experiment results. According to this finding, the structures of the droplets can be designed by applying UV curing at different stages of the phase separation, and the monodispersity of droplets is necessary to achieve polymerized particles with the same structure.