Excellent soft magnetic properties have been achieved in a wide metal volume fraction (x) range for as-deposited (Fe65Co35)x(SiO2)1−x granular films fabricated by magnetron sputtering. With the decrease in x from 0.7 to 0.5, the films exhibit small coercivity Hc not exceeding 4 Oe and high electrical resistivity ρ up to 5.48 × 103 µΩ cm. A minimum Hc value of 1.7 Oe was obtained for the sample of x = 0.57 with ρ = 2.86 × 103 µΩ cm. At a frequency lower than 1.3 GHz, the real part μ′ of complex permeability of this sample is about 170 and then decreases with frequency while the imaginary part μ″ is visible when f > 1 GHz, which may be caused by anisotropy dispersion. The FMR frequency is as high as 2.4 GHz, implying a high cut-off frequency for high frequency applications. A study of high resolution transmission electronic microscope indicates that the samples consist of Fe65Co35 particles uniformly embedded in an insulating SiO2 matrix. The excellent soft magnetic property is ascribed to exchange coupling among magnetic particles. The investigation of the Δm–H curve evidences the existence of this inter-granule interaction.
A simple and effective way was developed to prepare antibacterial poly(methyl methacrylate) (PMMA) materials from commercial PMMA and synthesized poly[2-(tert-butylamino) ethyl methacrylate] (PTBAEMA) by solution blending and solvent evaporation methods. The chemical structure of as-synthesized PTBAEMA was characterized by FTIR and 1 H-NMR, and the molecular weight (M w ) and polydispersity index was determined by Gel Permeation Chromatograph. The two components, that is, PMMA and PTBAEMA, were partially miscible and of regular domain size and shape as revealed by SEM observation. Antibacterial assay revealed PMMA/PTBAEMA blends inherited the good antibacterial activity of PTBAEMA against both Staphy-lococcus aureus and Escherichia coli, no matter whether the bacteria were waterborne or airborne. Besides, the antibacterial performance of PMMA/PTBAEMA blends depended on the M w and dosage of PTBAEMA, and type of bacteria strain. Furthermore, it was proved that PMMA/PTBAEMA blends killed bacteria on direct contact without releasing active component, which sufficiently met the demand of developing environment-friendly antibacterial materials.
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