CHARACTERIZATION OF CO-FE MAGNETIC FILMS FABRICATED BY GALVANO-STATIC ELECTRODEPOSITION

In this research, nanocrystalline Co-Fe coatings were electrodeposited on copper substrate. The influence of current density on different properties of the films at two pH levels was investigated. All the coatings showed nodular structure with rougher morphology at higher current densities. Due to anomalous deposition at higher current density, the amount of iron content increased and reached its maximum value at about 50 wt.% for the coating obtained from pH 5. X-ray diffraction patterns showed hcp structure as the dominant phase. However, by increasing current density at lower pH value, a double phase structure containing fcc+hcp phases was detected. It was observed that current density has a positive effect on grain refinement. However, coarser grains would obtain at lower pH value. Microhardness measurements showed that, there is a direct relationship between grain size and microhardness. Moreover, microstructure in double phase structure films can influence microhardness more dominantly. Vibrating sample magnetometer (VSM) measurements indicated that the saturation magnetic is proportion to deposited iron content and reached its maximum value at about 1512 emu/cm3. It was cleared that grain size, phase structure and chemical composition can affect coercivity of the films effectively

Design of thermosensitive polymer‐coated magnetic mesoporous silica nanocomposites with a core‐shell‐shell structure as a magnetic/temperature dual‐responsive drug delivery vehicle

A stimuli-responsive nanocomposite with a core-shell-shell structure consisting of iron oxide (Fe3O4) nanoparticles as core, mesoporous silica as middle shell, and poly(N-isopropyl acrylamide-co-acrylic acid) (P[NIPAAm-co-AAc]) as an exterior shell with thermo-responsivity properties was synthesized to be used as a magnetic/temperature responsive drug delivery system. The structure, morphology, and size of P(NIPAAm-co-AAc)-coated mesoporous silica embedded magnetite nanoparticles (P(NIPAAm-co-AAc)@mSiO2@Fe3O4) were characterized by XRD, FTIR, and TEM analyses. Also, the heating ability of mesoporous silica-coated Fe3O4 nanoparticles, and P(NIPAAm-co-AAc)@mSiO2@Fe3O4 nanocomposites was investigated under the exposure of an alternating magnetic field (AMF). The results indicated that the prepared nanocomposites could generate enough heat for hyperthermia applications. Moreover, the magnetic/temperature-responsive drug release behavior of P(NIPAAm-co-AAc)@mSiO2@Fe3O4 nanocomposites loaded with fluorouracil (5-FU) was studied under the exposure of the AMF (frequency = 120 kHz, and amplitude = 22 kA m−1), as well as two different temperatures (37°C and 45°C). The results showed that only 7.8% of the drug could be released after 20 h at 37°C (below the LCST of the copolymer). In contrast, by increasing the temperature of release medium up to 45°C (above the LCST of the copolymer), the amount of released drug was increased up to 47%. Moreover, by exposing the prepared nanocomposite to a safe AMF, a burst release of drug was observed, indicating the excellent responsivity of the carrier to an external magnetic field. These results proved that the obtained nanocomposite has a great performance to be used as a magnetic/temperature-sensitive drug carrier for advanced drug delivery applications