Flexible Cotton Fabric-Based Ionizing Radiation Dosimeter for 2D Dose Distribution Measurements over a Wide Dose Range at High Dose Rates.

This work presents an ecological, flexible 2D radiochromic dosimeter for measuring ionizing radiation in the kilogray dose range. Cotton woven fabric made of cellulose was volume-modified with nitrotetrazolium blue chloride as a radiation-sensitive compound. Its features include a color change during exposure from yellowish to purple-brown and flexibility that allows it to adapt to various shapes. It was found that (i) the dose response is up to ~80 kGy, (ii) it is independent of the dose rate for 1.1-73.1 kGy/min, (iii) it can be measured in 2D using a flatbed scanner, (iv) the acquired images can be filtered using a mean filter, which improves its dose resolution, (v) the dose resolution is -0.07 to -0.4 kGy for ~0.6 to ~75.7 kGy for filtered images, and (vi) two linear dose subranges can be distinguished: ~0.6 to ~7.6 kGy and ~9.9 to ~62.0 kGy. The dosimeter combined with flatbed scanner reading and data processing using dedicated software packages constitutes a comprehensive system for measuring dose distributions for objects with complex shapes.

The Surface Modification of Papers Using Laser Processing towards Applications.

This work presents the results of paper laser processing. It begins with the selection and examination of the processing parameters, then an examination of the properties of the modified papers and examples of applications of the developed modification method. The properties of laser-modified paper were studied using reflectance spectrophotometry to examine the colour aspects of the modified papers, scanning electron microscopy (SEM) and confocal microscopy for a morphological analysis, and Raman spectroscopy to analyse the papers under the influence of laser light. The influence of laser processing on the wettability of paper and the evenness of unprinted and printed paper was also investigated. The knowledge gained on paper surface modification with laser light was used to propose several applications, such as methods of marking, tactile detection, the controlled removal of optical brightener, ink, and metallised coatings from paper packaging, highlighting the design and aesthetics of paper. The developed laser-assisted method shows a promising, ecological approach to the design of many value-added paper products.

Capsule Dosimeters for Ultraviolet Radiation Measurements on Coral Reefs and in Seawater.

This work reports on the new chemical dosimeters for UV radiation dose measurements on coral reefs and in seawater. The proposed dosimeters can measure the actual dose of UV radiation, which consists of 95% UVA and 5% UVB radiation, unlike the currently-used radiometers in marine and ocean waters that measure the dose of UVA and UVB radiation separately. The dosimeters are composed of water, poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127) as a gel matrix, and 2,3,5-triphenyltetrazolium chloride (TTC) as a UV radiation-sensitive compound. In the work, the dosimeters were characterised in terms of their response to the dose of UV radiation depending on the TTC concentration and the irradiation and storage conditions of the dosimeters. The stability of the dosimeters over time was also examined. The obtained results indicate that the TTC-Pluronic F-127 dosimeters can be used to measure absorbed doses of UV radiation in the saltwater environment. The developed dosimeters with a concentration of 0.1% TTC can be used up to 5 J/cm2, which predisposes them to UV radiation measurements at a depth of more than 10 m in sea and ocean waters in 10-min intervals during all months throughout the year.

Multi-Color Printed Textiles for Ultraviolet Radiation Measurements, Creative Designing, and Stimuli-Sensitive Garments.

This work concerns the new idea of textile printing with a multi-color system using pastes containing compounds sensitive to ultraviolet (UV) radiation. A screen printing method based on a modified CMYK color system was applied to a cotton woven fabric. Aqueous printing pastes were prepared from thickening and crosslinking agents and UV-sensitive compounds: leuco crystal violet (LCV), leuco malachite green (LMG), and 2,3,5-triphenyltetrazolium chloride (TTC) instead of the system's standard process colors: cyan, magenta, and yellow. Depending on the number of printed layers and the type of UV radiation (UVA, UVB, and UVC), the modified textile samples change color after irradiation from white to a wide range of colors (from blue, red, and green to purple, brown, and gray). Based on reflectance measurements, the characteristic parameters of the one-, two-, and three-color-printed samples in relation to absorbed dose were determined, e.g., dose sensitivity, linear and dynamic dose response, and threshold dose. This printing method is a new proposal for UV dosimeters and an alternative standard for textile printing. Furthermore, the developed method can be used for the securing, marking, and creative design of textiles and opens up new possibilities for such stimulus-sensitive reactive printing.

Golden and Silver-Golden Chitosan Hydrogels and Fabrics Modified with Golden Chitosan Hydrogels.

Golden and silver-golden chitosan hydrogels and hydrogel-modified textiles of potential biomedical applications are investigated in this work. The hydrogels are formed by reactions of chitosan with HAuCl4·xH2O. For above the critical concentration of chitosan (c*), chitosan-Au hydrogels were prepared. For chitosan concentrations lower than c*, chitosan-Au nano- and microgels were formed. To characterise chitosan-Au structures, sol-gel analysis, UV-Vis spectrophotometry and dynamic light scattering were performed. Au concentration in the hydrogels was determined by the flame atomic absorption spectrophotometry. Colloidal chitosan-Au solutions were used for the modification of fabrics. The Au content in the modified fabrics was quantified by inductively coupled plasma mass spectrometry technique. Scanning electron microscopy with energy dispersion X-ray spectrometer was used to analyse the samples. Reflectance spectrophotometry was applied to examine the colour of the fabrics. The formation of chitosan-Au-Ag hydrogels by the competitive reaction of Au and Ag ions with the chitosan macromolecules is reported.

Study of NBT-Pluronic F-127 Gels as 1D UV Radiation Dosimeters for Measurement of Artificial Light Sources.

This work reports on radiochromic dosimeters for 1D UV light measurements. The dosimeter is composed of a 25% Pluronic F-127 that forms a physical gel matrix and nitro blue tetrazolium chloride (NBT) as a radiation-sensitive compound. This dosimeter was exposed to UVA, UVB and UVC radiation, and the radiochromic reactions were followed with reflectance spectrophotometry including changes in light reflectance and color coordinates in the CIELAB color system. The exposition of dosimeters to all UV radiation caused color changes from pale yellow to dark violet, and its intensity increased with increasing absorbed dose. The effects of NBT concentration and UV radiation type on the dose-response of the dosimeters were also examined. The results obtained reveal that the dosimeters are the least sensitive to irradiation with UVC and the most sensitive to irradiation with UVB (e.g., dosimeter with 2 g/dm3 of NBT was characterized by the following parameters: the threshold dose 0.1 J/cm2; the dose sensitivity -5.97 ± 0.69 cm2/J; the linear dose range 0.1-2.5 J/cm2; the dynamic dose range was equal to 0.1-3 J/cm2). The results obtained reveal that the NBT-Pluronic F-127 dosimeters can be potentially useful as 1D sensors for artificial UV radiation sources measurements.

Discolouring 3D Gel Dosimeter for UV Dose Distribution Measurements.

This work reports on a new TBO-Pluronic F-127 three-dimensional (3D) gel dosimeter for UV light dose distribution measurements. The optimal gel composition was found to be 60 µM Toluidine Blue O (TBO), which acts as a UV-sensitive compound; 5% w/w hydrogen peroxide (H2O2), which is necessary for initiation of TBO photodegradation and 25% w/w poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127), which forms a physical gel matrix. The dosimeter becomes discoloured when exposed to UV radiation and a discolouration is the more intense, the higher the absorbed dose is. The samples after irradiation with UVA, UVB and UVC radiation were measured using UV-Vis spectrophotometry to obtain the basic dose-response characteristic of the dosimeter, including dose sensitivity, linear and dynamic dose range, threshold dose, stability over time and dose-response for fractioned and non-fractioned doses. Additionally, the TBO-Pluronic F-127 gel dosimeter was investigated for spatial stability and the ability to measure the dose distribution of UV radiation. The results obtained indicate that the TBO-Pluronic F-127 dosimeter is a promising UV sensor and 2D/3D UV dosimeter.