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Coating of Glass Microspheres
Published in Giancarlo C. Righini, Glass Micro- and Nanospheres, 2019
Davor Ristić, Mile Ivanda, Maurizio Ferrari, Andrea Chiappini, Giancarlo C. Righini
The microsphere itself is usually made from silica or from some other dielectric material. For dielectrics, E0 corresponds to the energy of the bandgap. Since for most glasses the position of the energy gap exhibits a red shift with the increase in temperature [40], the second part of Eq. (4.8) will generally be positive in the transparent region of the glass absorption spectrum (E ≪ E0), becoming negative close to the bandgap. In the region of interest for the application of microspheres, which spans from visible to the near-infrared, the second part of Eq. (4.8) is usually dominant over the first one, making the thermo-optic coefficient positive. For silica, which is the material most widely used for the production of microresonators, the thermo-optic coefficient dN/dT and the thermal expansion coefficient α have values ≈10−5 K−1 and ≈10−6 K−1, respectively.
Nano Resveratrol: A Promising Future Nanonutraceutical
Published in Bhupinder Singh, Minna Hakkarainen, Kamalinder K. Singh, NanoNutraceuticals, 2019
Chahinez Houacine, Kamalinder K. Singh
Microspheres are spherical microscopic particles with size ranging from 1 to 1,000 nm. However, defining these on the basis of size can sometimes be obscure, since spheres with a size of more than 1,000 nm may still be called microspheres. Such microparticles have wide-ranging possible applications (Figure 10.4a). Since resveratrol is an extremely light-sensitive compound, functionalized monodisperse porous polymeric microspheres of about 5 nm in diameter have been employed as material for preservation and stabilization of resveratrol. It was observed that cyano-functional groups in the microspheres contributed greatly toward stability of resveratrol in the porous microparticles. The entrapped resveratrol maintained its antioxidant activity (93%), much better compared to pristine resveratrol, and slow release of entrapped resveratrol from porous microparticles sustained its bioactivity for more than 5 weeks (Nam et al., 2005).
Glossary of scientific and technical terms in bioengineering and biological engineering
Published in Megh R. Goyal, Scientific and Technical Terms in Bioengineering and Biological Engineering, 2018
Microspheres are small spherical particles, with diameters in the micrometer range (typically 1 μm to 1000 μm (1 mm)). Microspheres are sometimes referred to as microparticles. Microspheres can be manufactured from various natural and synthetic materials.
Synthesis of silica microspheres on silicon-modified carbon foams under ablation
Published in Materials and Manufacturing Processes, 2019
Bin Wang, Li Hejun, Bugao Xu, Yulei Zhang
Lightweight microspheres have drawn widespread attentions in the last decade, due to their particular specific surface, outstanding functionalities, good chemical reactivity, as well as wide applications in microelectronics, absorbents, drug delivery, and so on.[1–4] Silica microspheres (SMs) have been proved enormous potential in the field of biotechnology, absorption, catalyst for their unique geometric structure, thermal stability, and amazing mechanical properties.[5–9] Similar to many other inorganic microspheres, sol–gel[6] and post-modification[7] synthesis have been used to form SMs as simple methods. However, such techniques inevitably give rise to high cost and sophisticated process, even require removal of impurity, which need a long cycle for SMs preparation. It remains a huge challenge today to develop SMs efficiently. Therefore, it is necessary to find a new way for SMs’ high-efficiency production.
Facile fabrication of silk fibroin microparticles: their characterization and potential adsorption study
Published in Journal of Dispersion Science and Technology, 2021
N. Parushuram, R. Ranjana, B. Narayana, M. Mahendra, Y. Sangappa
Microspheres or microparticles are generally a class of particulates that have diameters from high nanometer (1–1000 nm) to micron range (1–1000 µm) and assume a spherical shape.[19] These particulates are fabricated using ceramics, polymers, and their composites via several techniques/procedures. In literature, several methods or procedures are well documented. The important methods are laminar jet breakup,[20] lipid templating,[21] water-in-oil emulsification-diffusion,[22] spray drying,[23] and self-assembling of regenerated SF.[6] In addition, recombinant spider silk-mimetic peptides are also used to create microspheres[24] and microcapsules.[25] These methods are effective at producing micro- to nanoscale particles; the particle size distribution is generally very broad. SF microspheres can also be produced by blending SF with polyvinyl alcohol (PVA) to elude the use of organic solvents.[9] Synthetic polymers and many of the natural polymers require organic solvents, surfactants, cross-linkers, and harsh conditions in order to produce micro- and nanospheres.[26] Therefore, in this research, it is proposed to use a simple and very effective procedure to fabricate SF microparticles wherein the SF blends with low-molecular-weight hydroxyl propyl methyl cellulose (HPMC) polymer. HPMC is cellulose ether commonly used in the food industry as an emulsifier, protective colloid, stabilizer, suspending agent, and as a thickener or film former.[27]
Synthesis and radiation grafting modification of hydroxyl controlled AM/HEMA polymer microspheres
Published in Journal of Dispersion Science and Technology, 2021
Zhiyong Wang, Meiqin Lin, Zhaoxia Dong, Juan Zhang, Zihao Yang
A variety of polymer microspheres are used in many fields, such as medicine, biology, catalysis, oil recovery, etc. However, most polymer microspheres are smooth particles, which do not have advantages when used in oil production industry. Because the displacement fluid is used to expand the sweep area and improve the sweep efficiency, the polymer particles with smooth surface are insufficient. Therefore, it is necessary to modify the polymer microsphere with smooth surface to make it have a large sweep efficiency and have a wider application in the oil production industry.