Influence of sericin/TiO2 nanocomposite on cotton fabric: part 1. Enhanced antibacterial effect.

Sericin as a biological material was extracted from raw silk by boiling in hot water and nano-TiO2 was dispersed in its solution. The prepared finishing agents with and without polycarboxylic acid cross-linking agents were treated on cotton fabric using pad-dry-cure. Presence of sericin, nano-TiO2, and cross-linking agents on cotton fabric was confirmed by at least one of the following experimental FTIR, SEM, EDX, and XRD. The antibacterial activity and the durability of modified cotton fabrics were investigated against one Gram-positive bacterium (Staphylococcus aureus) and one Gram-negative bacterium (Escherichia coli). The finishing treatment on the cotton fabric was more effective against S. aureus than E. coli. The fabrics treated with nano-TiO2 were possessed more activity against bacteria as compared to sericin and also considerably improved with given nanocomposite. The antibacterial activity of treated fabrics with cross-linking agents has not been considerably changed after 20 and 40 launderings. The fabrics treated with given nanocomposites did not dramatically affect the breaking strength.

Novel durable bio-photocatalyst purifiers, a non-heterogeneous mechanism: accelerated entrapped dye degradation into structural polysiloxane-shield nano-reactors.

This research has designed innovative Ag/TiO(2) polysiloxane-shield nano-reactors on the PET fabric to develop novel durable bio-photocatalyst purifiers. To create these very fine nano-reactors, oppositely surface charged multiple size nanoparticles have been applied accompanied with a crosslinkable amino-functionalized polysiloxane (XPs) emulsion. Investigation of photocatalytic dye decolorization efficiency revealed a non-heterogeneous mechanism including an accelerated degradation of entrapped dye molecules into the structural polysiloxane-shield nano-reactors. In fact, dye molecules can be adsorbed by both Ag and XPs due to their electrostatic interactions and/or even via forming a complex with them especially with silver NPs. The absorbed dye and active oxygen species generated by TiO(2) were entrapped by polysiloxane shelter and the presence of silver nanoparticles further attract the negative oxygen species closer to the adsorbed dye molecules. In this way, the dye molecules are in close contact with concentrated active oxygen species into the created nano-reactors. This provides an accelerated degradation of dye molecules. This non-heterogeneous mechanism has been detected on the sample containing all of the three components. Increasing the concentration of Ag and XPs accelerated the second step beginning with an enhanced rate. Further, the treated samples also showed an excellent antibacterial activity.

A smart dynamic self-induced orientable multiple size nano-roughness with amphiphilic feature as a stain-repellent hydrophilic surface.

Recently developing bioinspired super-hydrophobic surfaces to achieve self-cleaning properties has been driving numerous researches. However, hydrophilicity is one of the most important features of garment comfort. Therefore, accomplishing self-cleaning and stain repellency on hydrophilic surfaces would be a high topic of interest. This research is concerned with wettability mechanism; static and dynamic study of contact angle through water droplet absorption on the multiple scale nano-roughness covered by different weight ratio of oppositely charged inorganic nanoparticles and amino-functionalized polysiloxane. The results revealed that the second layer of the resin formed on the surface can show an amphiphilic hybrid block copolymer-like feature whose dual action can be intensified during water droplet absorption by the created multiple size nano-roughness. This unique structure can create a stain repellent but hydrophilic surface with exceptional advantages. The mechanism has been deeply discussed according to the evidence on droplet edge interfacial energy changes as a driving force to overcome meta-stable Cassie state on the multiple size nano-roughness with amphiphilic feature. A lotus-like nano-roughness has been also observed on the SEM micrographs. Based on a statistically approached experimental design, the effect of variant factors on droplet absorption time, static, advancing, receding contact angles and self-cleaning properties has been mathematically modeled according to the response surface methodology (RSM).