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Manufacturing Methods of PLA Composites
Published in Jyotishkumar Parameswaranpillai, Suchart Siengchin, Nisa V. Salim, Jinu Jacob George, Aiswarya Poulose, Polylactic Acid-Based Nanocellulose and Cellulose Composites, 2022
Guang-Way Bill Jang, Cheng-Han Hsieh, Allen Lai, Sagle Chan
Polyelectrolytes bond with cellulose materials through ionic interaction. Thus, ionic density and distribution, as well as the presence of salt, will influence the efficiency of polyelectrolyte modification of cellulose. Electrostatic assembly of two negatively charged nanomaterials, nanosilver, and NC fibers, was mediated by subsequent adsorption of a positively charged polyelectrolyte, such as polydiallyldimethylammonium chloride, polyallylamine hydrochloride, and polyethyleneimine, followed by a negatively charged polyelectrolyte onto the surface of NCF. The adsorbed polyelectrolytes served as a linkage between NCF and Ag nanoparticles for the preparation of antibacterial paper [20].
Basics of Resonance
Published in Banshi Dhar Gupta, Anand Mohan Shrivastav, Sruthi Prasood Usha, Optical Sensors for Biomedical Diagnostics and Environmental Monitoring, 2017
Banshi Dhar Gupta, Anand Mohan Shrivastav, Sruthi Prasood Usha
The SMOs that have been used for LMR sensing applications include indium tin oxide (ITO), zinc oxide (ZnO), indium oxide (In2O3), and tin oxide (SnO2). The selection of SMO for application depends on the properties and compatibility of the material with the desired environment in which it has to work. The high conductivity of SMO material in the infrared region of electromagnetic spectrum supports sensor realization using SPR technique. In contrast, the optical transparency of the SMO material in the visible region of electromagnetic spectrum supports sensor based on LMR technique. The thickness of SMO material such as ITO also varies the conductivity of the material, which needs to be taken care of. A unique property of the LMR-based sensors is the generation of multiple LMR dips or a certain RI of the surrounding medium. Hence, by analyzing the maximum shift in resonance wavelength generated by each dip for a range of RI change, the best LMR dip can be chosen for the sensing purpose. The SMO-LMR-based sensors also possess high sensitivity due to the high value of the real part of the RI of SMO (Zamarreno et al. 2012). ZnO, one of the SMOs, exhibits dual property. One of the properties is supporting LMR and the other is the direct immobilization of biorecognition element by acting as a matrix which simplifies the fabrication process of biosensor probe (Usha et al. 2017). In addition, the chemisorption feasibilities on SMOs help in realizing a single SMO-layered LMR sensor probe as a high-sensitive gas sensor for environmental monitoring applications (Usha et al. 2015). Besides SMOs, polymers such as polyacrylic acid (PAA), polyallylamine hydrochloride (PAH), and polystyrene sulfonate (PSS) and their layer-by-layer combinations support LMR since their dielectric properties satisfy the conditions discussed above (Del Villar et al. 2012, Zamarreno et al. 2013). However, incompatibility of the polymers with certain viscous analytes limits their application in sensing.
Synthesis and characterization of magnetic nanoparticles coated with polystyrene sulfonic acid for biomedical applications
Published in Science and Technology of Advanced Materials, 2020
Bo-Wei Chen, Yun-Chi He, Shian-Ying Sung, Trang Thi Huynh Le, Chia-Ling Hsieh, Jiann-Yeu Chen, Zung-Hang Wei, Da-Jeng Yao
Polystyrene sulfonic acid (PSS) is a hydrophilic chain-like polymer derived from polystyrene with SO3− functional groups that has been reported for its antithrombotic and anticoagulant functions, as well as modulating activities of heparin-binding growth factors [15–19]. In aqueous applications, SO3− groups are typically bonded or electrostatically attracted to an amino or diazo group and form covalent or non-covalent bonds between polymers [15,16,20]. In many cases, PSS can form polyelectrolyte multilayers or microcapsules in the presence of polyallylamine hydrochloride (PAH) with a layer-by-layer technique. The multilayers composed of PSS and PAH possess positive and negative charges in alternate layers; the films hence maintain structural stability in the absence of a chemical bond. Recent tests demonstrated that the multilayer PSS-PAH microcapsules can serve as fluorescent hydrophobic nanorods [21] or nanocarriers for drug doxorubicin [20]. PSS alone in the solvent can form micelles under vigorous stirring because of the hydrophilic group (-SO3H−) and hydrophobic alkyl group; it is therefore able to encapsulate nanomaterials and as-synthesized nuclei to form particles of size in a range of tens of nanometers [18]. Compared with polystyrene, which is one of the common polymers used for decorating MNPs, PSS possess stronger negative charge that can enhance both steric hindrance and electrostatic repulsions between nanoparticles when PSS is coated on the surface. Accordingly, PSS has an advantage over the uncharged or weakly charged hydrophilic polymers for nanoparticle biocompatibility by forming well-dispersed particles with narrow size distribution in the solvent whose properties closed to the biofluid of human body.