poly(vinylidene fluoride) (pvdf) fibers with two molecular weights were prepared via electrospinning process. in this process, the concentration of spinning depended drastically on the gelation process. also, it was experimentally smaller than obtained concentration in the solution entanglement number approach (sena). proof of this incompatibility was explained by the properties of pvdf and its...

Poly (N-isopropylacrylamide) (pNIPAm) is one of the most completely studied “smart” polymers due to its unique reversible thermoresponsivity.That is, when pNIPAm in water is heated > ~31°C, it transits from a random coil to a globule conformation; this transition is reversed when T < ~31°C. This conformational change is accompanied by water exchange process. When pNIPAm undergoes the coil to gl...

We report on a capillary-based microfluidic platform for the fabrication of non-spherical sodium alginate microgels. The sodium alginate droplets were crosslinked off-chip in a mixture of barium acetate and glycerol solution. Novel morphologies such as tear drop, lamp-like, mushroom-like, double-dimpled and bowl-like microgels were fabricated by controlling the size, impact velocity (at the cro...

Patterned porous surfaces with responsive functionalities are fabricated by a thermoresponsive microgel-assisted breath figure (BF) process. When water droplets submerge into a polystyrene (PS) solution during formation of a porous surface by the bottom-up BF process, poly(N-isopropylacrylamide)-co-acrylic acid (PNIPAm-co-AA) microgels dispersed in the solution spontaneously assemble at the wat...

We describe a route towards self-assembled colloidal molecules, where thermoresponsive microgels serve as discrete, externally tunable interaction sites. The ability of poly(N-isopropylacrylamide) (PNIPAM) and poly(N-isopropylmethacrylamide) (PNIPMAM) microgels to adsorb to the oil/water (O/W) interface and create Pickering-stabilized mini-emulsions was first tested using the controlled additio...

Nowadays, electrospinning has emerged as a widespread technology to produce nanofibers and best candidates for many significant applications. The most important challenge is to attain uniform nanofibers. In these cases, controlling the production of electrospun nanofiber becomes important. However, Analysis dynamics of jet formation and its instability is difficult during the process. For makin...

The release of the opioid antagonist naltrexone from neutral poly(N-isopropylacrylamide) (PNIPAAM) microgels and negatively charged PNIPAAM microgels containing acrylic acid groups (PNIPAAM-co-PAA) has been studied at various microgel and drug concentrations. The release curves were found to be well represented by the Weibull equation. The release rates were observed to be dependent on the micr...

Microfluidics (MFs) offers a promising method for the preparation of polymer microgels with exquisite control over their dimensions, shapes and morphologies. A challenging task in this process is the generation of droplets (precursors for microgels) from highly viscous polymer solutions. Spatial separation of MF emulsification and gelation of the precursor droplets on chip can address this chal...

Cell-laden microscale hydrogels (microgels) can be used as tissue building blocks and assembled to create 3D tissue constructs with well-defined microarchitecture. In this article, we present a bottom-up approach to achieve microgel assembly on a patterned surface. Driven by surface tension, the hydrophilic microgels can be assembled into well-defined shapes on a glass surface patterned with hy...

We present a bottom-up approach to direct the assembly of cell-laden microgels to generate tissue constructs with tunable microarchitecture and complexity. This assembly process is driven by the tendency of multiphase liquid-liquid systems to minimize the surface area and the resulting surface free energy between the phases. We demonstrate that shape-controlled microgels spontaneously assemble ...