Silica matrix is an appropriate medium for physical and chemical binding of different compounds, among them antimicrobial agents. A nanocomposite coating with AgCl dispersed in a reactive organic-inorganic binder was applied on the cotton fabric by pad-dry-cure and exhaustion methods. The results of the antimicrobial tests showed that the embedment of AgCl in the silica matrix does not inhibit its antimicrobial activity, as well as does not significantly improve its washing resistance. Therefore the activity of AgCl decreases after repetitive washing.
COBISS.SI-ID: 2820968
Biodegradation of cellulose fibres could be successfully decreased with the chemical finishing, where the sol-gel technology is of great importance. In this study, the differences between the active and passive antimicrobial protection are discussed. While the active antimicrobial activity is assured with the application of antimicrobial agents, the passive one is caused by the presence of repellent and easy-care agents which decrease the surface free energy of fibres and crosslink the fibres amorphous regions. This minimizes adhesion of microbes and hinders their penetration into the fibres.
COBISS.SI-ID: 2401392
The influence of antimicrobial activity of two contemporary finishes, specifically a dispersion of colloidal silver (Ag) and 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride (Si-QAC), on the degree of biodeterioration of 100% cotton (CO) fabric and fabric composed of a mixture of cotton and polyester (CO/PES) with the ratio 50:50 was studied. Ag was chosen for the leaching agent, while Si-QAC was used as the biobarrier-forming agent. The biodeterioration of samples finished with different concentrations of Ag and Si-QAC was analysed from a standard soil burial test after 3, 6 and 12 days of exposure to soil microflora. SEM micrographs revealed intensive biodeterioration of the unfinished cellulose fibres, while the highly biologically resistant polyester fibres remained undamaged. A controlled release of Ag successfully inhibited biodeterioration of the cellulose fibres in the CO and CO/PES fabrics when its concentration reached a lethal, biocidal concentration. Contrary to the effects of Ag, the biobarrier formation of Si-QAC on CO and CO/PES fabrics was insufficient to protect the cellulose fibres during longer periods of soil burial, irrespective of its concentration. Intensive chemical changes to the cellulose were clearly seen from the FT-IR spectra of all of the samples. The resistance of the polyester component to biodeterioration did not provide any significant protection for the cotton component in CO/PES fabric.
COBISS.SI-ID: 2556272
The Langmuir-Blodgett (LB) method was used for depositing cubic polyhedral oligomeric silsesquioxanes (T8POSS) onto Au, indium tin oxide (ITO) and mica supports. Three different T8POSS were examined; two were amphiphilic and aggregated upon transfer to a solid support, while the highly symmetric POSS (termed MP8) gave stable and reproducible Langmuir films as studied by surface pressure and transfer ratio measurements. This was attributed to the eight identical alkanethiol groups located on each of the eight corners of the cubic like skeleton. The LB films were studied by RA-FTIR, XPS, contact angle and cyclic voltammetry. These techniques revealed the formation of a permeable, yet, stable layer. The symmetric MP8 was utilized as a bridging building block between the support and Au nanoparticles (Au-NPs). This assembly was examined by means of AFM, SEM and anodic oxidation of the nanoparticles. An average density of 1.45-109 nanoparticles cm-2 was obtained for the deposited Au-NPs on the MP8 layer. Furthermore, anodic stripping voltammetry was used for studying the extraction of Hg2+ by the MP8 LB film. This work is important for understanding the formation of thin coatings of the POSS molecules on other flexible and soft materials, such as textiles.
COBISS.SI-ID: 4783642
In this research, we succeeded to introduce a novel two-step procedure for chemical modification of cellulose fibres with antimicrobial activity, which included the pad-dry-cure method to apply a reactive inorganic-organic hybrid sol-gel precursor (RB) followed by the in situ synthesis of AgCl particles on the RB-treated fibres. This process enabled the preparation of fibres with highly effective and durable antimicrobial properties at a sufficient concentration of AgNO3 in the solution. The results showed that this application process yields the following important benefits: (i) the in situ synthesis enabled a simple and environmentally friendly preparation of AgCl particles from AgNO3 and their embedment into the fibres; (ii) the presence of the RB silica matrix increased the fibres’ capacity for adsorbing AgCl particles compared with the same fibres without RB; (iii) the AgCl particles were bound to the RB silica matrix by physical forces, which allowed for their controlled release from the fibres; (iv) the modified cellulose fibres provide a 100% bacterial reduction even after 10 repeated washing cycles; and (v) chemical modification did not significantly change the fibres whiteness, wettability or softness.
COBISS.SI-ID: 36032773