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Fei, Haojie; Saha, Nabanita; Zandraa, Oyunchimeg; Moučka, Robert; Kazantseva, Natalia E.; Wang, Gengchao; Bao, Hua; Sáha, Petr
Engineering; Materials Science; Biochemistry, Genetics and Molecular Biology; graphene oxide; SI-ATRP; reduction; hybrids; polymer brushes; green synthesis; silver nanoparticles; zeta potential; dielectric properties; e-beam writer; silicon nitride membranes; nano patterning; anisotropic etching; spiral grating structure; phyllotactic pattern; magnetic nanoparticle; hydrogels; biomineralized MNP; magnetic hydrogel; PVP-CMC; Flexible supercapacitors; hydrogel electrolyte; bacterial cellulose; in-situ; photocatalysis; semiconductor; LED diode; photocatalytic reactor; powder material; on-line measurement; ultrasound; poly(ethylene oxide); magnetic nanoparticles; magnetorheology; electrospinning; Iron oxide nanoparticles; Dextran; Core - shell nanoparticles; Hyperthermia; multicore particles; magnetic interaction; specific loss power; hyperthermia; ion beam milling; optoelectronic device; scanning electron microscopy (SEM); diamond saw; iron oxide nanoparticles; gadolinium; chitosan; theranostic; controlled release; doxorubicin; graphene; surface modification; atom transfer radical polymerization; poly(methyl methacrylate); nanoparticles; composite; MEH-PPV
conference paper description
Properties of the resulting polymer nanofibers are often tailored by sonication technique applied prior or past an electrospinning process. The aim of this contribution is to evaluate morphology of nanofibrous mats formed by poly(ethylene oxide) with distributed magnetic nanoparticles (MNP) (about 20 nm in diameter) in dependence on time of sonication of the used polymer solutions. The solutions were exposed to sonication (intensity 200W, frequency 24 kHz) for 10, 30, and 60 minutes. It was shown that rheological characteristics (viscosity, storage and loss moduli) strongly depend on time of sonication (particularly phase angle) in contrast to electric conductivity and surface tension. For analysis of homogeneous distribution of MNP in polymer solution, the rheological measurements were carried out also in presence of external magnetic field. Magnetorheological efficiency (a relation of corresponding viscosities) was determined for 80, 170, and 255 mT. Consequently, changed rheological characteristics participate significantly in the process of electrospinning and resulting quality of the obtained nanofibrous mats. Qualitative changes were described by means of scanning electron microscopy (variance of mean diameter of nanofibers), transmission electron microscopy (distribution of MNP within nanofibrous mats). Static magnetic properties were determined by a vibration sample magnetometer. It was shown that even distribution of MNP in the mats can be achieved by mere sonication process without application of external magnetic field during an electrospinning process. However, time of sonication generates a degree of embedding of MNP into individual nanofibers.