Development of Functional Textiles Through Micro-encapsulation

Essential oils are used for medical and technical textiles' functionality, giving them new properties. The most commonly used method is encapsulation, which ensures greater functionality and durability. Microencapsulation protects small solid, liquid or gaseous particles by a coating system (1–1000 mm). The encapsulated material is called the core, and the material that forms the coating of the particles is the wall or encapsulating agent. The encapsulating material can be a natural, synthetic or semi-synthetic polymeric layer. Textiles made by knitting technology from fibrous mixtures with content of: Cotton/Elastane, Cotton/Polyester and 100% Polyester were treated by padding, to offer antibacterial properties. The impregnation module consists of a padding machine with 2 vertical/horizontal oscillating rollers, acquired from Roaches International LTD. The first treatment solution (R1) containing pine essential oil and collagen hydrolysate was obtained. 450 μL of pine essential oil was dissolved in 15 mL of ethyl alcohol. The pine essential oil solution was added over the 1.5% collagen solution together with zeolite and β-cyclodextrin (pine essential oil: zeolite: β-cyclodextrin ratio of 1:10:10). The second treatment solution (R2) containing doxycycline and collagen hydrolysate was obtained (doxycycline: β-cyclodextrin ratio of 1:10). After the treatment, the samples were dried at room temperature for 24 h. The treatment solutions were characterised by: DLS analysis (dynamic light scattering) with the Zetasizer nano NZ device from Malvern Instruments Limited UK used for the characterization of particles with sizes between 0.3 nm – 10 μm. The particle size in solution R1 was within the limits of 11-20 µm. The particle size in solution R2 was within the limits of 274.6 nm-1.169 µm. Optical microscopy using an Olympus BX43 microscope equipped with a WHN10x/22 eyepiece and a Plan N 40x/0.65 Ph2 objective, and scanning electron microscopy (drop-casting on copper slide) with magnifications of 4000X and 16000X and EDAX for compositional analysis were used for solutions analysis (R1 and R2). SEM images for R1 revealed granular formations with an average size of 516 µm (4000X) and 4.95 µm (8000X) and a density of granules of 365 granules per 128 µm×148 µm=18944 µm2 (area of the SEM image at 2000X magnification), resulting in a surface density of 1.92 granules/100 µm2. EDAX analyses reveal the elemental composition of the R2 solution consisting mainly of Oxygen-51.73%, silicon oxide-21.19% and Nitrogen-11.66%, Na, C, Al, Cl, K, Ca. GS-MS analysis for both the pine essential oil and the treated textile structures revealed the presence of specific chemical compounds. GS-MS analysis for both the pine essential oil and the treated textile structures revealed the presence of specific chemical compounds.The antibacterial activity, according to SR EN ISO 20645/2005, was evaluated on Staphylococcus aureus ATCC 6538 (gram-positive) and Escherichia coli ATCC10536 (gram-negative) strains and showed a satisfactory effect of treatments with R1 and R2 because no bacterial growth was observed.