A dye-doped polymer-dispersed liquid crystal (PDLC) is an attractive material for application in smart windows. Smart windows using a PDLC can be operated simply and have a high contrast ratio compared to those of other devices that employed photochromic or thermochromic material. However, in conventional dye-doped PDLC methods, dye contamination can cause problems and has a limited degree of commercialization of electric smart windows. Here, we report on an approach to resolve dye-related problems by encapsulating the dye in monodispersed capsules. By encapsulation, a fabricated dye-doped PDLC had a contrast ratio of >120 at 600 nm. This fabrication method of encapsulating the dye in a core-shell structured microcapsule in a dye-doped PDLC device provides a practical platform for dye-doped PDLC-based smart windows.
Using a Couette-Taylor (CT) crystallizer, a non-isothermal technique was developed for effective control of the crystal size distribution (CSD) of the suspension. The proposed technique is based on the internal heating−cooling cycle in a non-isothermal CT crystallizer, consisting of a hot cylinder (T h ) and cold cylinder (T c ). Thus, an internal loop of fines destruction of the suspension in the heating boundary layer of the hot cylinder and recrystallization in the cooling boundary layer of the cold cylinder is formed by the periodic circulating flow of the Taylor vortex in the non-isothermal CT crystallizer. The efficiency of the heating−cooling cycle for improving the CSD depends on the non-isothermal mode and nonisothermal parameters. When the inner cylinder temperature is hot and the outer cylinder temperature is cold (Mode-I), this is more efficient for improving the mean crystal size and dispersity of the CSD than when the cylinder temperatures are reversed (Mode-II). In addition, the efficiency of the heating−cooling cycle is optimized using the temperature difference between hot and cold cylinders (ΔT = T h − T c ) and saturated bulk temperature. The Taylor vortex fluid motion is always found to enhance the internal cycle efficiency. Thus, the initially small crystal size and broad CSD of the seed suspension (230 μm of mean crystal size and 81% of coefficient of variation) are improved to a large crystal size and narrow CSD of the product suspension (1020 μm of mean crystal size and 31% of coefficient of variation) at a non-isothermality of 8.7 ± 0.1 °C, saturated bulk temperature of 24.0 °C, and rotation speed of 800 rpm. The variation of the cycle efficiency is explained in terms of the driving forces for heating dissolution and cooling recrystallization.
We report a simple and bio-friendly method to synthesize platinum (Pt) and nitrogen (N)-doped carbon@silica using polydopamine (PDA). This silica-based composite permits greater humidifying capacity to sufficiently hydrate membrane electrode assemblies (MEAs), thus improving electrochemical properties for polymer electrolyte membrane fuel cells (PEMFC).
Single microbial cell encapsulation in hydrogels is an important task to find valuable biological resources for human welfare. The conventional microfluidic designs are mainly targeted only for highly dispersed spherical bioparticles. Advanced structures should be taken into consideration for handling such aggregated and non-spherical microorganisms. Here, to address the challenge, we propose a new type of cylindrical-shaped micropillar array in a microfluidic device for enhancing the dispersion of cell clusters and the isolation of individual cells into individual micro-hydrogels for potential practical applications. The incorporated micropillars act as a sieve for the breaking of Escherichia coli (E. coli) clusters into single cells in a polymer mixture. Furthermore, the combination of hydrodynamic forces and a flow-focusing technique will improve the probability of encapsulation of a single cell into each hydrogel with a broad range of cell concentrations. This proposed strategy and device would be a useful platform for genetically modified microorganisms for practical applications.
Selective filtering of target biomaterials from impurities is an important task in DNA amplification through polymerase chain reaction (PCR) enhancement and gene identification to save endangered animals and marine species. Conventional gene extraction methods require complicated steps, skilled persons, and expensive chemicals and instruments to improve DNA amplification. Herein, we proposed an alternative method for overcoming such challenges by imparting secondary functionality using commercially available polyurethane (PU) sponges and cost-effective fabrication approaches through polydopamine and polysiloxane coatings. The porous, highly flexible, and chemically modified superhydrophilic and superhydrophobic PU sponges allow large surface areas and mechanically stable frames for effective extraction of genomic DNA through selective filtering of fish tissues and oils. Furthermore, these chemically modified PU sponges allow separation of genes and improvement of PCR for DNA amplification for the identification of fish species. The combination of a simple fabrication method and functionalized PU sponges could be a useful platform for PCR enhancement and gene-based identification of species for practical applications.
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