Recently, there has been a strong interest in providing fabrics with greater wearing comfort while remaining fresh and odor free as well as the ability to impart antimicrobial properties. The innovative combination of controllable topographical and chemical modifications of the material will be a step forward for surface engineering towards real life application: to make surfaces less liable to microbial adhesion, or easier to be cleaned, with the addition of an antimicrobial agent. The fabric surfaces are not only exposed to abrasion and wear caused by daily contacts, but also to aggressive laundry procedures. So far, many different methods have been studied using approaches such as polymeric grafting or polymeric coating accompanied by lack of stability. Thus, higher mechanical and chemical stabilities become mandatory properties for such materials and need to be taken into consideration during the design process. Using plasma-based process techniques, thereby obtaining a highly stable and homogenous functional surface could be a potential alternative. Materials and Methods Cotton knit fabric samples were were cut into size of 1×1 cm~2 and cleaned in successive baths of acetone and diethyl ether anhydrous for 10 minutes before being used. Surface modifications were performed using a hybrid plasma enhanced chemical vapor deposition (PE-CVD) reactor, operating at 13.56 MHz at room temperature. Hydrogen and nitrogen (N_2:H_2) were used as gas precursors for plasma pre-treatment of cotton fabric to enhance antimicrobial dye uptake. Methane was used for deposition of biocidal doped amorphous carbon (aC) nanocoating on the cotton fabric. Chemical state of surface was characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The wettabillty of the surfaces after each modification has been measured using static water contact angle (WCA). The antibacterial activity of the treated fabric was estimated against Escherichia coli (ATCC 11229). To evaluate durability of wash, a hospital laundry process was chosen. Results: The morphological changes due to plasma treatments were investigated by SEM as shown in Figure 1. It reveals a fairly smooth surface for untreated and N2:H2 pretreated samples, whereas nanocoating deposition caused a significant morphological change. Surface chemical composition analyses, by XPS, exhibited that the aC deposition was efficient as carbon became the major component of the surface: 95.4 at.% for nanocoated sample versus 67 at.% for untreated one. N2:H2 pretreated samples displayed high amount of nitrogen (at.%). Depending on plasma modification process the wetting behavior of cotton fabric could be tailored. Indeed, the WCA demonstrate the effect of plasma treatment by changing untreated cotton fabric wettability from ～ 100° to hydrophobic state (～145°) or hydrophilic state (～80°) by aC nanocoating and N2:H2 pretreatment, respectively. Antibacterial test revealed that nanocoated samples as well as N2:H2 pretreated samples with antimicrobial agents shown antibacterial activity against E. Coli as compared to untreated cotton fabric before and after laundry. Discussion and Conclusions: Our results clearly show the feasibility of low temperature plasma based process to modify the surface of fabric towards tuning the wetting behavior and antibacterial property. Moreover, stable antibacterial activity has been achieved by deposition of nanocoating on the surface of cotton fabric. The goal of the present work was to propose an appropriate treatment for functionalization of cotton fabric, which can be applied by textile industry using ecofriendly and non-toxic agents and processes.
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