Stimuli-responsive microgel, based on synthetic polymer (poly-NiPAAm) and biopolymer (chitosan), was incorporated onto cotton fabric surface by pad-dry-cure method using 1,2,3,4-butanetetracarboxylic acid (BTCA) as crosslinker. In order to assess the moisture management properties of cotton functionalized with responsive microgel, the effects of temperature, relative humidity and concentration of microgel on water vapour transmission rate (WVTR) and moisture content (MC) were quantified. Since the use of experimental design is considered as a highly attractive feature in dealing with experiments and variables of this nature, the effects were quantified by using a central composite design. The regression equations obtained from the statistical analysis allowed the prediction of WVTR and MC at different ambient conditions. Material properties such as crease recovery and whiteness were also measured. The results indicate that both relative humidity and temperature significantly influence studied responses (WVTR and MC), showing that good perspiration can be achieved at lower humidity levels and at higher temperatures. The observed phenomena are attributed to controlled expansion (or contraction) of the surface incorporated microgel, which acts as a sensor of temperature and as a valve to regulate the water vapour permeability of functionalized cotton.

Peracetic acid is a well‐known alternative to hydrogen peroxide as a bleaching agent for cotton. In this study, a novel cationic bleach activator, N‐[4‐(triethylammoniomethyl)benzoyl]butyrolactam chloride, was used in combination with peracetic acid to investigate the enhancement of cotton bleaching efficiency. The effects of temperature, pH and concentrations of activator and peracetic acid on the bleaching performance were studied using a statistical design of experiment. Adding activator to a peracetic acid bleaching bath improved the resultant whiteness of the substrate and at optimal conditions produced less fibre damage than when peracetic acid was used alone. In addition, the bleaching performance of both peracetic acid and hydrogen peroxide in the presence of activator was compared. In the absence of activator, the peracetic acid performance was considerably superior to a conventional hydrogen peroxide bleach system in which no bleach activator is present. However, addition of activator to the hydrogen peroxide bath increased the whiteness to a level comparable to peracetic acid.

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An innovative strategy for functional finishing of cotton involves application of stimuliresponsive surface modifying system based on temperature-and pH-responsive poly-NiPAAm/chitosan microgel. The stimuli-responsiveness implied to cotton is the consequence of swelling/collapse of the microgel particles incorporated to the fibre surface, which produces an active liquid management system. The performance of functionalized cotton fabric in terms of liquid management properties was assessed by choosing appropriate techniques (water uptake; thin-layer wicking; water retention capacity; and drying capability) and discussion of the results was based on the types of water that are expected to be present in hydrated cotton and stimuli-responsive microgel.

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