Controlling morphology of polymer microspheres by Shirasu porous glass (SPG) membrane emulsification and subsequent polymerization: from solid to hollow

Physicochemical and Adsorption Characteristics of Divinylbenzene-co-Triethoxyvinylsilane Microspheres as Materials for the Removal of Organic Compounds

In this work, organic-inorganic materials with spherical shape consisting of divinylbenzene (DVB) and triethoxyvinylsilane (TEVS) were synthesized and investigated by different complementary techniques. The obtained microspheres may be applied as sorbent systems for the purification of organic compounds from water. The hybrid microspheres combine the properties of the constituents depending on the morphologies and interfacial bonding. In this work, the influence of the molar ratio composition of crosslinked monomer (DVB) and silane coupling agent (TEVS) (DVB:TEVS molar ratios: 1:2, 1:1 and 2:1) on the morphology and quality of organic-inorganic materials have been examined. The materials were analysed using small angle X-ray scattering (SAXS) analysis, low-temperature nitrogen sorption, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) to provide information on their structural and surface properties. Moreover, thermal analysis was performed to characterize the thermal stability of the studied materials and the adsorbent-adsorbate interactions, while adsorption kinetic studies proved the utility of the synthesized adsorbents for water and wastewater treatment.

Protective microencapsulation of β-lapachone using porous glass membrane technique based on experimental optimisation

Even though β-lapachone is a novel drug with pharmacological activity, it has limitations including instability under light conditions. The main purpose of the study was to enhance the stability of β-lapachone using the microencapsulation method. The Shirasu porous glass membrane was used to achieve uniform-sized microcapsules. The prepared microcapsules were evaluated to investigate how process parameters affect the encapsulation efficiency, photostability and particle size distribution. The experimental design was conducted to obtain optimal formulations. In addition, an operating space was drawn to identify the safer range of control factors. All control factors showed significant effects on the encapsulation efficiency and photostability. For example, when a large amount of polymers was used, encapsulation efficiency and photostability were improved. However, as the amount of polymers increased, large and polydisperse microcapsules were produced. The robust design method provided information to characterise significant factors, thereby allowing effective control of photostability and size of microcapsules.

Synthesis of polymeric nano-objects of various morphologies based on block copolymer self-assembly using microporous membranes

Polymeric nano-objects of a range of morphologies have been prepared using a novel approach based on the use of microporous membranes for mixing of a solvent (containing a diblock copolymer) and a non-solvent.

Structured microparticles with tailored properties produced by membrane emulsification

This paper provides an overview of membrane emulsification routes for fabrication of structured microparticles with tailored properties for specific applications. Direct (bottom-up) and premix (top-down) membrane emulsification processes are discussed including operational, formulation and membrane factors that control the droplet size and droplet generation regimes. A special emphasis was put on different methods of controlled shear generation on membrane surface, such as cross flow on the membrane surface, swirl flow, forward and backward flow pulsations in the continuous phase and membrane oscillations and rotations. Droplets produced by membrane emulsification can be used for synthesis of particles with versatile morphology (solid and hollow, matrix and core/shell, spherical and non-spherical, porous and coherent, composite and homogeneous), which can be surface functionalised and coated or loaded with macromolecules, nanoparticles, quantum dots, drugs, phase change materials and high molecular weight gases to achieve controlled/targeted drug release and impart special optical, chemical, electrical, acoustic, thermal and magnetic properties. The template emulsions including metal-in-oil, solid-in-oil-in-water, oil-in-oil, multilayer, and Pickering emulsions can be produced with high encapsulation efficiency of encapsulated materials and narrow size distribution and transformed into structured particles using a variety of solidification processes, such as polymerisation (suspension, mini-emulsion, interfacial and in-situ), ionic gelation, chemical crosslinking, melt solidification, internal phase separation, layer-by-layer electrostatic deposition, particle self-assembly, complex coacervation, spray drying, sol-gel processing, and molecular imprinting. Particles fabricated from droplets produced by membrane emulsification include nanoclusters, colloidosomes, carbon aerogel particles, nanoshells, polymeric (molecularly imprinted, hypercrosslinked, Janus and core/shell) particles, solder metal powders and inorganic particles. Membrane emulsification devices operate under constant temperature due to low shear rates on the membrane surface, which range from (1-10)×10(3) s(-1) in a direct process to (1-10)×10(4) s(-1) in a premix process.

Fabrication of Microcapsules for Dye-Doped Polymer-Dispersed Liquid Crystal-Based Smart Windows

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.