K‐M theory of fabric knitted by three‐channel rotor spun wool yarn

Two‐component and three‐component color blended yarns were spun by red, yellow, and blue wool slivers using a three‐channel rotor spun machine, and the corresponding plain fabrics were knitted. The color‐matching models of K‐M theory were built with the relative method and the least squares method, respectively. Colors and blending ratios of the fabrics were predicted by the model. The results showed that the average color differences of the samples predicted by the two methods are both about 1.0 and the mean value of the proportional error is below 3%. The least squares method has a better color‐matching effect for the three‐component sample, and the relative value method has better color‐matching results for the two‐component sample. When the tolerance range is 2.0, the pass rates of the samples predicted by either the relative value method or the least squares method reach 100%.     

Synthesis and thermal properties of poly(n‐butyl acrylate)/n‐hexadecane microcapsules using different cross‐linkers and their application to textile fabrics

This study focused on the preparation, characterization, and determination of thermal properties of microencapsulated n‐hexadecane with poly(butyl acrylate) (PBA) to be used in textiles with heat storage property. Microcapsules were synthesized by emulsion polymerization method, and the particle size, particle size distribution, shape, and thermal storage/release properties of the synthesized microcapsules were analyzed using Fourier‐transform infrared spectroscopy, scanning electron microscopy, and differential scanning calorimetry techniques. Allyl methacrylate, ethylene glycol dimethacrylate, and glycidyl methacrylate were used as cross‐linkers to produce unimodal particle size distribution. MicroPBA microcapsules produced using allyl methacrylate cross‐linker were applied to 100% cotton and 50/50% cotton/polyester blend fabrics by pad‐cure method. The mean particle size of microcapsules ranges from 0.47 to 4.25 μm. Differential scanning calorimetry analysis indicated that hexadecane in the microcapsules melts at nearly 17°C and crystallizes at around 15°C. The contents of n‐hexadecane of different PBA microcapsules were in the range of 27.7–50.7%, and the melting enthalpies for these ratios were between 65.67 and 120.16 J/g, respectively. The particle size and thermal properties of microcapsules changed depending on the cross‐linker type. The cotton and 50/50% cotton/polyester blend fabrics stored 6.56 and 28.59 J/g thermal energy, respectively. The results indicated that PBA microcapsules have the potential to be used as a solid‐state thermal energy storage material in fabrics. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Hue and warm‐cool feeling as the visual resemblance criteria for iso‐CCT judgment

The hue perception and ‘warm‐cool’ feelings were investigated, in response to various lighting settings, following the adaptation to either 3500K or 5000K to compare which one—between conventional iso‐Correlated Color Temperature (CCT) and a new one based on CIE u'v′ color space—is more compatible with the visual perception. Twenty participants evaluated hue and warm‐cool feelings for 48 test lighting settings, by observing an empty gray booth. The results showed that yellow‐blue and ‘warm‐cool’ feelings are closely located around the Planckian locus, while red‐green roughly follows the line orthogonal to the Planckian locus in CIE u'v′ color space, at both 3500 K and 5000 K settings. This suggests that u'v′ color space correlates better with human perception.     

Preparation and properties of Fe(II)‐ion‐sensitive colour‐changing fabric

Textile fabrics were dyed with complexometric indicators (ionochromic dyes) to develop Fe(II) ionochromic fabric. Three kinds of ionochromic dye were used to dye silk fabric, and they were evaluated for colour changes triggered by Fe(II) solution. The K/S values and photos of the fabrics were then recorded. It was found that 1,10‐phenanthroline was the most suitable ionochromic dye in these dyes. Colour change from white to red could be clearly seen when 1,10‐phenanthroline‐dyed silk fabric was triggered by Fe(II) solution, but it showed no colour change when triggered by Cu(II), Mg(II), or Ca(II) solution. Moreover, 1,10‐phenanthroline‐dyed nylon, polyester, and cotton fabrics showed no obvious colour changes after triggering by Fe(II) solution. Ion concentration, pH value, and reaction time could affect the colour changes. When triggered by 8 mg l^?1 of Fe(II) solution at neutral pH for about 15 min, the ionochromic fabric showed a clear colour change. In addition, three coloured fabrics in green, blue, and yellow were also dyed with 1,10‐phenanthroline. It was found that they could also show clear colour changes when triggered by Fe(II) solution. These ionochromic fabrics may find broad application in many fields, such as Fe(II) detection, magic toys, anticounterfeiting materials, and bionic silk flowers.     

Cytocompatible and regenerable antimicrobial cellulose modified by N‐halamine triazine ring

This study reports the formation of cyanuric chloride hydrolysate and its attachment onto cellulose fibers though covalent bonding. The hydrolysis product, 2,4‐dichloro‐6‐hydroxy‐1,3,5‐triazine, is prepared in water solution at ambient temperature, and directly used as a treatment solution for the treatment of cotton fabrics without any prior work‐up. The triazine treated fabrics are rendered antimicrobial through exposure to chlorine bleach. The oxidative chlorine bonded to the triazine‐treated cotton is very stable and regenerable to standard washing tests and UVA irradiation test. The N‐halamine modified cotton fabrics demonstrate excellent antimicrobial efficacy against Staphylococcus aureus ATCC 6538 and Escherichia coli O157:H7 ATCC 43895 with 7‐logs reductions within the contact time of 10 and 5 min, respectively. In addition, the results of in vitro cell viability test suggested that the N‐halamine modified fabrics have excellent cytocompatibility to mammalian cells. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40627.     

Categorical color constancy under RGB‐LED light sources

The light‐emitting diode (LED)‐based light sources have been widely applied across numerous industries and in everyday practical uses. Recently, the LED‐based light source consisting of red, green and blue LEDs with narrow spectral bands (RGB‐LED) has been a more preferred illumination source than the common white phosphor LED and other traditional broadband light sources because the RGB‐LED can create many types of illumination color. The color rendering index of the RGB‐LED, however, is considerably lower compared to the traditional broadband light sources and the multi‐band LED light source (MB‐LED), which is composed of several LEDs and can accurately simulate daylight illuminants. Considering 3 relatively narrow spectral bands of the RGB‐LED light source, the color constancy, which is referred to as the ability of the human visual system to attenuate influences of illumination color change and hold the perception of a surface color constant, may be worse under the RGB‐LED light source than under the traditional broadband light sources or under the MB‐LED. In this study, we investigated categorical color constancy using a color naming method with real Munsell color chips under illumination changes from neutral to red, green, blue, and yellow illuminations. The neutral and 4 chromatic illuminants were produced by the RGB‐LED light source. A modified use of the color constancy index, which describes a centroid shift of each color category, was introduced to evaluate the color constancy performance. The results revealed that categorical color constancy under the 4 chromatic illuminants held relatively well, except for the red, brown, orange, and yellow color categories under the blue illumination and the orange color category under the yellow illumination. Furthermore, the categorical color constancy under red and green illuminations was better than the categorical color constancy under blue and yellow illuminations. The results indicate that a color constancy mechanism in the visual system functions in color categories when the illuminant emits an insufficient spectrum to render the colors of reflecting surfaces accurately. However, it is not recommended to use the RGB‐LED light source to produce blue and yellow illuminations because of the poor color constancy.     

Practical color barrier‐free illumination for deuteranopia using LEDs

Here, we propose a color barrier‐free illumination consisting of white, red, and blue LEDs for people with deuteranopia‐type defects in color perception. Color perceptions of 20 volunteers with normal vision and four examinees of deuteranopia were evaluated by both the Ishihara test for color blindness and the Farnsworth Panel D‐15 test under color barrier‐free illumination. The illumination was comparably effective, not only for discriminating between red and green but also for discrimination of the hues on a color chip continuously. © 2014 Wiley Periodicals, Inc. Col Res Appl, 40, 218–223, 2015     

Temperature‐sensitive poly(N‐tert‐butylacrylamide‐co‐acrylamide) hydrogels bonded on cotton fabrics by coating technique

Different from the conventional method of developing stimuli‐sensitive textiles by graft copolymerization of environmental responsive polymers onto the fabric, the coating technique was applied to bond temperature‐sensitive hydrogels with cotton fabric through chemical covalent in our work. A temperature‐sensitive linear copolymer of N‐tert‐butylacrylamide (NTBA) and acrylamide (AAm) was prepared in methanol. Then, the cotton fabrics were coated using an aqueous solution of this copolymer containing 1,2,3,4‐butanetertracarboxylic acid as a crosslinker and sodium hypophosphite (SHP) as a catalyst, followed by drying and curing. The surface of the cotton fabrics was bonded on more or less coatings of poly (NTBA‐co‐AAm) hydrogels, as verified by Fourier transform infrared spectroscopy and scanning electron microscopy images. The poly(NTBA‐co‐AAm) hydrogels‐coated fabrics exhibited temperature sensitive, and the temperature interval of the deswelling transition was higher than lower critical solution temperature of linear copolymer solution. The coated fabrics presented good water‐impermeable ability because of the swelling of hydrogels bonded, especially when the add‐on was as high as 14.14%. Environmental scanning electron microscopy images revealed that coating hydrogels swelled and covered on the surface as a barrier to prevent water from penetrating once the coated fabric came into contact with water. The findings demonstrate that the temperature‐sensitive hydrogels can be covalently bonded on the cotton fabrics by coating technique and the coated fabrics have potential on immersion fabrics. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The study of colour fastness of commercial microencapsulated photoresponsive dye applied on cotton,cotton/polyester and polyester fabric using a pad‐dry‐cure process

Commercial microencapsulated photoresponsive dye was applied on cotton, polyester/cotton and polyester fabric using a pad‐dry‐cure process. Colour fastness of the photoresponsive fabrics to washing, wet cleaning, dry cleaning, rubbing and light was investigated. The CIELAB colour values of the fabrics before and after testing were measured using a reflectance spectrophotometer, and the colour differences were calculated to evaluate the fastness properties. The fabrics had better colour fastness to wet cleaning and washing than to dry cleaning. The fabrics showed higher colour fastness to wet than to dry rubbing. The photoresponsiveness of the fabrics decreased with prolonged exposure time to artificial light due to low photostability of the microcapsules.     

Using carbon black nanoparticles to dye the cationic‐modified cotton fabrics

Carbon black (CB) aqueous dispersion was prepared and used to dye the cationic‐modified cotton fabrics through exhaust dyeing process. The effects of CB concentration, CB nanoparticles size, dyeing bath pH, dyeing time and dyeing temperature were investigated. The color yields of dyed fabrics were evaluated on Kubelka‐Munk value K/S. The surface morphologies of cationic modified and nonmodified cotton fabrics were measured by video microscope. The fabrics presented 18.9 of the color yield with the dyeing conditions: the dyeing solution contained 2% o.w.f. CB and dyeing at 80°C for 30 min with pH 13 using a 50 : 1 liquor ratio. The images of the video microscope demonstrated a clear surface profile for the cationic‐modified cotton fabrics dyed with smaller CB particle size solutions. These results indicated that CB nanoparticles were suitable for dyeing the cotton fabrics. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Direct coloration of textiles with photochromic dyes. Part 1: Application of spiroindolinonaphthoxazines as disperse dyes to polyester,nylon and acrylic fabrics†

1,3,3‐Trimethylspiroindoline‐2,3′‐3H‐naphth[2,1‐b][1,4]oxazine ( 1a ) and 6′‐piperidino‐1,3,3‐trimethylspiroindoline‐2,3′‐3H‐naphth[2,1‐b][1,4]oxazine ( 1b ) were applied as disperse dyes to polyester, nylon and acrylic fabrics. Under optimised dyeing conditions, photochromic fabrics were produced which, on irradiation with ultraviolet or exposure to sunlight, turned blue ( 1a) or blueish‐purple ( 1b ). Dye 1a showed enhanced photochromic colour change performance compared with dye 1b . The photochromic colour build was highest on nylon and lowest on acrylic fabric. The colour change properties and the technical performance (wash fastness and photostability) of the photochromic fabrics were evaluated using specifically adapted colour measurement methods. The data were analysed in terms of variation of lightness, a*, b*, chroma, hue angle and ΔE, colour difference before and after exposure, and K/S curves as a function of irradiation time. The fabrics generally showed good wash fastness. Although the colour build‐up decreased with exposure to the Xenotest fadeometer, some residual photochromism remained after prolonged exposure.     

UV–Vis irradiation fatigue resistance improvement of azo photochromic compound using polyurethane‐chitosan double shell encapsulation

Double shell photochromic microcapsules were prepared by in situ polymerization with polyurethane and chitosan as inner and outer shell respectively. FT‐IR indicated that chitosan‐glutaraldehyde copolymer formed by imine and combined with polyurethane photochromic nanocapsules. The polyurethane‐chitosan microcapsules exhibited a near‐spherical shape, and the average particle size of nanocapsules was around 1.2 μm. The half‐life of azo compound increased from 135 to 340 min after encapsulated in polyurethane‐chitosan microcapsules. The polyurethane‐chitosan shell delayed the coloration process for 14 s compared with azo compound in ethanol, however, the absorbance of azo compound increased by 17.15% in polyurethane‐chitosan microcapsules. It decreased from 0.3486 to 0.1738 in ethanol during 20 s, however, it decreased from 0.4084 to 0.2625 in polyurethane‐chitosan microcapsules in 55 s when it reached steady state during decoloration process. Polyurethane‐chitosan double shell encapsulation is an effective route for improving the fatigue resistance, increasing the absorbance of azo compound. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40895.     

Microencapsulation and application of fluorine‐free water repellent agent‐AH102

Fluorine‐free water repellent agent, AH102, was microencapsulated by interfacial polymerization with polyurethane as shell material to restrict its hydrolysis and improve its dispersibility in water. The appearance of the resultant microcapsules was characterized with optical microscope and scanning electron microscope. Chemical structure of microcapsules was identified with Fourier‐transforming infrared spectrometer. The size and size distribution of the microcapsules were determined by laser particle size analyzer. The thermal property of the microcapsules was investigated by thermogravimetric analysis. The stability and dispersibility of the microcapsules in aqueous medium were characterized by evaluating the static water contact angles of the treated cotton fabrics with the emulsions of unencapsulated and microencapsulated AH102 at different storage intervals. The results showed that AH102 was successfully encapsulated and its stability and dispersibility in water were greatly improved. As expected, the emulsion of the microencapsulated AH102 became more stable than that of the unencapsulated one at water repellence to cotton fabric with increasing storage intervals. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Color vision assessment‐3. An efficient,two‐step,color assessment protocol

Color vision tests and multi‐test protocols in current use often fail to detect small changes in red/green (RG) and yellow/blue (YB) color vision due to poor sensitivity. The tests also have low specificity. In this study, we examine how improved understanding of within‐ and inter‐subject variability in RG and YB color vision and accurate assessment of the differences in color thresholds between the least‐sensitive, age‐matched normal trichromats, and the least‐affected deutans and protans can be used to design an efficient color vision screener (CVS) test. To achieve this objective, we examined two extensive data sets from earlier studies and carried out new experiments to provide better estimates of within‐subject variability in color thresholds and to validate the CVS test. The data sets provide essential information on inter‐subject variability, the effects of normal aging on RG and YB thresholds, and the spread in RG color thresholds in deutan and protan subjects. A statistical model was developed to optimize the parameters of the CVS test and to predict the limits of what can be achieved in color assessment. The efficiency and repeatability of the CVS test were then assessed in 84 subjects. The results match model predictions and reveal close to 100% test efficiency. The test takes between 140 and 160 seconds to complete and has close to 100% repeatability. An efficient, “two‐step” protocol based on the initial use of the CVS test followed by full color assessment in only those who fail the CVS test is also described.     

Nucleoside‐Based Diarylethene Photoswitches: Synthesis and Photochromic Properties

Diarylethene photoswitches based on the natural nucleoside deoxyadenosine were designed and synthesized. In aqueous solution, some of them exhibited good photochromic properties, including clear changes in color upon irradiation at 365 nm, red‐shifts of the absorption wavelength, with good fatigue resistance, thermal stability, conversion efficiency, and base‐pairing properties.     

Color matching of fiber blends: Stearns‐Noechel model of digital rotor spun yarn

Stearns‐Noechel model was utilized as a primary reference to study color matching principles of digital rotor spun yarn. Three primary colored (red, yellow and blue) cotton fibers were used to spin blended yarns. Spectral reflectance of the two‐component and three‐component samples was measured with data color spectrophotometer. For these samples, the Stearns‐Noechel model parameter M was determined. Four methods were employed to calculate the M value to improve accuracy of the model, 1.Classical method, named as M1; 2.Optimizing the M1 value obtained by the classical method considering the wavelength factor, named as M2; 3.Simplified M2 according to the linear correlation with the wavelength, named as M3; 4. Simplified M2 according to the segmentation correlation with the wavelength, named as M4. The study shows that average color difference of the two‐component decreases from 2.7 to 1.48, and for three‐component samples from 3.32 to 1.66, by using M2 instead of M1. While calculated using M3, the color difference of the two types of samples will be 1.73 and 2.19, correspondingly. This cannot meet color matching needs. As for M4, the average color difference of the two categories will be 1.54 and 1.91, better than the result obtained using M1 and M3, worse than M2.     

Automatic detection of layout of color yarns of yarn‐dyed fabric. Part 3: Double‐system‐Mélange color fabrics

Automat layout detection of color yarns is necessary for weaving and producing processes of yarn‐dyed fabrics. This study presents a novel approach to inspect the layout of color yarns of double‐system‐mélange color fabrics automatically, which is Part III of the series of studies to develop a computer vision‐based system for automatic inspection of color yarn layout for yarn‐dyed fabrics. The inspection of single‐system‐mélange color fabrics has been realized in Part I of the series of studies. Integrating the projection‐based region segmentation method proposed in Part I and the FCM‐based stepwise classification method proposed in Part II, the proposed approach is composed of three steps: (1) fabric region segmentation, (2) fabric region selection, and (3) layout of color yarns recognition. In the first step, the fabric regions are segmented by the projection‐based region segmentation method. In the second step, the reasonable fabric regions are selected by analyzing their color histograms and comparing their weft color's frequency. In the third step, the layout of color yarn is recognized by the FCM‐based stepwise classification method, and the precise layouts of color warps and wefts are produced. The experimental analysis proved that the proposed method can recognize the layout of color yarns of double‐system‐mélange color fabrics correctly by testing four different color fabrics and three pieces of same yarn‐dyed fabrics. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 250–260, 2017     

An investigation of an instrument‐based method for assessing colour fastness to light of photochromic textiles

A new method for evaluating the light fastness of photochromic fabrics was established, aimed at replacing the conventional method with an instrumental method. This method was based on comparing the colour difference of photochromic fabrics after light exposure with measured values of the colour differences of the blue wool references after fixed periods of light exposure. This method benefits from replacing the traditional visual evaluation of colour difference between exposed and unexposed areas of textile samples with a more accurate, instrument‐based measurement of the colour difference. The light fastness is then evaluated by comparing the colour difference with tabulated values of colour differences brought about by light exposure, for increased periods of time, of standard blue wool references. This method could be used for measuring light fastness of both traditional and photochromic fabrics. However, blue wool references and tested samples should be exposed to light under similar conditions when using this method to measure colour fastness to light of fabrics.     

Influence of chitosan posttreatment parameters on the fixation of pigment‐based inks on ink‐jet‐printed cotton fabrics

Cotton fabrics were digitally printed with pigment‐based black ink with an HP Desk‐Jet 880C printer. These ink‐jet‐printed fabrics were posttreated with chitosan samples for the fixation of the pigment‐based ink on the cotton. The influence of various parameters, including the molecular weight (MW), application method (pad–dry–cure vs pad–batch), concentration, and pH, on the degree of fixation (DF) of the pigment‐based inks was examined. The chitosan‐posttreated cotton samples were evaluated for their color strength, DF, color difference, and whiteness index values and their colorfastness properties. Chitosan samples with MWs of 150,000 and greater than 375,000 showed 100% (complete) fixation of the pigment‐based inks on the cotton fabrics. DF drastically decreased in the chitosan with an MW of less than 5000. Both the pad–dry–cure and pad–batch methods were found to be suitable for chitosan application onto ink‐jet‐printed fabrics. Chitosan with an MW of 150,000 showed 100% fixation at concentrations ranging from 0.3 to 1%. A further decrease in the concentration significantly decreased the fixation. High fixation values were achieved at acidic pH, whereas a neutral to alkaline pH resulted in poor fixation. The colorfastness properties for each parameter studied are also discussed. The posttreatment of the digitally printed cotton with chitosan was found to be very effective in fixing the pigment‐based inks. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Textiles screen‐printed with photochromic ethyl cellulose–spirooxazine composite nanoparticles

Photochromic compounds change colour on exposure to light, while the reversion may be attributable either to radiation or may be thermal. The use of photochromism on fabrics can provide new opportunities to develop smart textiles; for example, sensors and active protective clothes. Ethyl cellulose‐1,3‐dihydro‐1,3,3,4,5 (and 1,3,3,5,6) ‐pentamethyl‐spiro‐[2H‐indole‐2,3′‐(3H)naphtha(2,1‐b)(1,4)oxazine] composites were prepared by an oil‐in‐water emulsion, solvent evaporation method in order to form easily suspendable and fatigue‐resistant photochromic nanoparticles in screen‐printing paste. Their size was well below 1 μm and did not change substantially over a wide range of dye concentrations. After screen‐printing, a homogenous photochromic layer was built on a cotton substrate surface, which represented substantial blue colour development in CIELab colour space measurements because of ultraviolet light, even at a dye concentration of 0.045% w/w. The addition of a photodegradation inhibitor, Tinuvin 144, further increased the coloration of the printed fabric.