| In1991, the electrostatic self-assembly method proposed by Decher as an effective method to prepare multilayer films has caused great interests. Now it is widely used in polyelectrolyte, biological macromolecules, metal colloid particles, small inorganic particles and so on. By electrostatic self-assembly technique, two substances with opposite charge can form multilayer films by electrostatic force on a substrate. Due to the simple process, controllable thickness at nanoscale, uniform film structures and other outstanding features, electrostatic self-assembly technic has been widely used in the preparation of a variety of functional composite membranes. In this article, electrostatic self-assembly method is used to validate layering characteristics of multilayer films self-assembled with nano-silver particles and achieve surface functionalization cotton fabric by assembling nanoparticles of different shapes and types.Firstly, PDDA/AgNPs multilayers were assembled on the hydrolyzed PET film basement by electrostatic self-assembly method. The law of PDDA/AgNPs self-Assembly of multilayer films were also studied, which provided basis for nanoparticles self-assembly multilayers on fabric substrate. UV-vis, XPS, ICP, FESEM and AFM were used to characterize surface properties, chemical composition and morphology of PDDA/AgNPs multilayer. The results suggested that silver nano-particles were evenly dispersed on PDDA/AgNPs multilayer surface, without reunification, and it existed in the form of Ag0. Thermogravimetric analysis and dynamic mechanical analysis were used to study the thermal stability of PDDA/AgNPs multi-layer films, TG and DMA test results showed that the thermal stability of PET film assembled with10-layer nano-silver particles was improved. AgNPs/PDDA multilayers were assembled on cationic cotton fabric basement by electrostatic self-assembly method. The characteristics of cotton fabric before and after cationic modified were analyzed by FTIR spectra, and the results suggested that hyamine cationic were successfully introduced into cotton fiber surface. The absorbance of cotton fabrics assembled nano-silver particles of different layers by UV-vis, the results showed that the absorbance at410nm growed linearly with the assembly layers increasing. FESEM and AFM observation showed that there were intensive nano-particles on the fiber surface, and the nano-particles were evenly distributed, with no obvious agglomeration. Multilayer fabric strength test results showed that the cotton fabric strength loss was about10%after self-assembled with silver nanoparticles. According to TG and DTG results, the thermal stability of cotton fabric after assembled with nano-silver particles declined slightly, and it became more sensitive to thermal degradation, which was consistent with elongation results of cotton fabric mentioned earlier. Antibacterial experiment results showed that there were significant antibacterial circle in agar substrate inoculated experimental bacteria for cotton fabrics assembled with10-layer silver nanoparticles and the antibacterial circle radius was10mm, and the edge profile was relatively clear, which indicated the antibacterial effects was obvious.Blue silver nanoplate was adsorbed to cotton fiber surface by electrostaticity, meanwhile dyeing and antimicrobial finishing for cotton fabrics were conducted. Triangle slices were prepared by liquid-phase synthesis, the side length of triangle slices was about40nm, and its thickness was about3nm, and monitored silver nanoparticle synthesis procedure by UV-vis spectra. Silver nanoplate appeared three absorption peaks, that is, quadrupole resonance outside the surface in330nm, quadrupole resonance within the surface in390nm and dipole resonance within the surface in390nm. The effects of synthesis condition on the properties of triangular silver nanoparticles was studied and the synthesis mechanism of silver nanoplate was analyzed. The color change of cotton fabrics before and after assembled silver nanoplate and SEM images, both confirmed that the blue silver nanoplate are adsorbed to the cotton fabric basement. Antibacterial test for cotton fabric assembled with nano-silver particles was conducted by oscillation method, and the results showed that its bacteria resistance rate was87.06%, indicating that cotton fabric assembled with nano-silver particles had favorable antibacterial properties.TiO2as an efficient UV shielding agent, whose UV adsorption is very strong. TiO2colloidals with opposite surface electric charges were assembled on cotton fabric substrates to form multilayers by electrostatic self-assembly method. FESEM, AFM, ICP and XPS are used to characterize surface morphology and elements of multilayer fabrics assembled silver nanoparticles. The UPF value of nano-TiO2multilayer cotton fabrics was measured by UV protection factor testing instrument, the UPF value increased with the number of assembled layers increasing, and when the number of assembled layers was up to10layers, its UPF value was93.3, illuminating that the nano-TiO2multilayer cotton fabric had good anti-UV properties.In conclusion, this article provides a new way of thoughts and methods for nanoparticles adsorption on fabrics. Because the electrostatic self-assembly technology can use many kinds of assembled materials, which enriches fabric functional finishing by using nano-particles to some degree. |
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