Current immobiliza;on techniques oWen face significant challenges, including unevendistribu;on of enzymes, reduced enzyma;c ac;vity, and material waste, all of which can limitthe effec;veness of immobilized enzymes in industrial applica;ons. To address these issues,this study introduces a hydraulic spray automa;on system specifically designed for theimmobiliza;on of redox enzymes on tex;le substrates, providing a novel, resource-efficient,and con;nuous method for enzyme immobiliza;on. For this, glucose oxidase (GOx) waschosen as the model enzyme and was immobilized onto polyester tex;les (PET) using thehydraulic spray system. To op;mize the immobiliza;on process, several cri;cal parameters,including enzyme concentra;on, pickup percenatge, and the technique of layer-by-layerassembly of GOx was studied. Results revealed significant improvements in both the stabilityand ac;vity of the immobilized GOx, which are crucial for its effec;veness in industrialapplica;ons. Results showed that, the loading of GOx on PET had no influence on type of PET(ac;vated or pris;ne) used. However, surface ac;va;on offered be2er stability of GOxagainst rinse cycles. Results also showed that, with the increase of pickup percentage theac;vity of immobilized GOx increases un;l it reaches to the plateau. The results werepromising and demonstrated significance in uniformity and reduc;on in waste and ;meduring enzyme immobiliza;on. This immobiliza;on method not only minimizes resourceconsump;on by reducing waste but also facilitates large-scale produc;on, making itpar;cularly well-suited to meet the evolving demands of the industry. Ul;mately, this researchdemonstrates the poten;al of hydraulic spray automa;on technology to revolu;onize enzymeimmobiliza;on, paving the way for more sustainable and efficient industrial applica;ons.

This study introduces hydraulic spray (HS) atomizing system as new resource-efficient continuous dyeing-finishing method for wool fabric. Here, wool fabric was dyed and finished by using commercial dyes and finishes through either one-step or two-steps HS method. Results obtained from color strength (K/S), color difference (ΔECMC) and color fastness analysis presented the apprehension of HS method in dyeing of wool fabric with different GSM and dyes. Finishing performance of wool fabric was measured through water contact angle analysis. Analysis shows that, the finishing performance of HS method were substantial to reach water contact angle as high as 145° while maintaining high fastness to wash and abrasion. Between one-step and two-steps HS method, one-step method showed better performance with high resource efficiency compared to two-steps method. Results from statistical analysis shows no statistical significance of fabric weight, type of dyes, and finishes to the performance of new HS method which is crucial for true-scale industrial implementation and scaling up of this process. The findings of this report are of great importance as it presents a greener alternative to the conventional resource-intensive dyeing-finishing methods of wool fabric.

Although resource-efficient processes like inkjet printing have a large potential to foster the development of smart and functional textiles, one bottleneck still is the development of functional inks. To make inkjet printing and UV curing given production techniques for smart and functional specialty products, e.g. photochromic textiles, deepened knowledge about the development, rheological behavior and jetting behavior of functional ink is needed. This paper focuses on the formulation and performance of UV-responsive and UV-curable inkjet inks, which are based on photochromic dyes and their application to produce UV-responsive textiles. Two commercial photochromic dyes—Reversacol Ruby Red (RR) and Sea Green (SG), which represent dyes of the naphthopyran and spirooxazine class, respectively, have been used to develop the inks. The photochromic inks are characterized according to their physical–chemical and rheological properties in respect to temperature. The influence of temperature on the drop formation of the inks in an industrial print head is analyzed using a high-speed camera, which reveals important information regarding challenges in ink jettability. It was found that the dye structure and type used in the ink can influence the jetting behavior of photochromic UV-curable ink. More pronounced temperature sensitivity of dyes can increase the temperature-related effects of drop formation as was observed for SG ink. The printability of the RR and SG inks is framed and underpinned by theoretical calculations of the Z number. Discrepancies are observed and discussed between existing theory of ink jettability and visual evaluation of the photochromic ink.

Smart textiles have been a hot topic in research for several decades; however, comparatively few products can be found on the market. Resource-efficient processes can boost the breakthrough of smart and functional textiles, which often necessitate high-cost materials and only require small batches.

This thesis provides a technology-driven approach with resource-efficient solutions for the production of UV-sensing textiles, while pointing out the challenges of the new materials, which are created when novel production processes are used. The performance of UV-sensing textiles produced by ink jetting and UV curing of ink with commercial photochromic dyes is primarily explored. Several steps in the development of a UV-sensing textile are covered in thesis; development and jetting performance of the photochromic UV-curable inkjet ink, optimization of the color performance of photochromic prints using production process parameters by tuning color kinetics, and evaluation of the durability and textile character of photochromic textiles. Other focuses included in the thesis are dyeing of photochromic textiles with supercritical carbon dioxide (scCO2), novel ways of stabilizing photochromic prints and ink jetting of functional ink for sports and work wear.

It was shown that physical properties of the ink and temperature affected the jetting behavior of the ink. A discrepancy between the drop formation of UV-curable photochromic ink and existing models for jetting of inkjet ink was highlighted. Reversibly color-changing textiles can be produced with inkjet printing and UV curing of photochromic inks. The combination of the resource-efficient processes with the photochromic material required the introduction of an extended kinetic model to describe the coloration reaction of prints. An essential finding was that the kinetics of photochromic dyes in UV-curable ink applied on polyester fabric could be tuned using fabrication parameters during printing and curing in a continuous resource-efficient production process. By changing fabrication parameters during production, the prints’ crosslinking density is influenced and hence dye kinetics can be modified as a result of matrix rigidity of the UV ink. Furthermore, fabrication parameters influence and can be used to improve print durability as of abrasion and washing. Also, printing with photochromic UV-curable ink did not affect the fabric properties significantly in regards to flexibility and surface morphology. With the results obtained, photochromic textiles can be produced resource-efficiently using inkjet printing and UV curing, as well as scCO2 dyeing to boost the cost-effective and flexible production of smart textile UV sensors.

Photochromic molecules are well-established colourants in the manufacturing of niche products, providing reversible colour change effects when irradiated with ultraviolet (UV) light. The high material cost of such speciality dyes along with the general high carbon footprint and extensive water consumption of textile products necessitates resource-efficient production processes. The use of supercritical CO2 (scCO(2)) dyeing technique enables the economic production of textile high-end products, where a uniform through colouration is desired. This study investigates the potential application of two commercial photochromic dyes based on spirooxazine (Sea Green - SO-SG) and naphthopyran (Ruby Red - NP-RR) to polyester fabric using scCO(2) dyeing technique and examines their photochromic behaviour. The dyeing was carried out at 120 degrees C and 25 MPa for 1 h. The photochromic performance was evaluated using a specially designed online colour measurement system capable of simultaneous UV irradiation and continuous measurement of photochromic colour change even after the shutdown of the UV source. The colour yields (K/S values), photoswitching rates and durability against washing were the main parameters examined. The results showed that scCO(2) dyed photochromic polyester fabrics exhibited reversible colour changing properties upon UV exposure and removal. The samples dyed with SO-SG demonstrated a comparable degree of photo-colouration, lower background colour, faster colouration and decolouration speeds, but inferior wash fastness compared with NP-RR dyed samples. Particularly, the same class of dyes applied by scCO(2) dyeing showed faster fading rates compared with conventionally dyed and screen printed samples. This study shows that scCO(2) dyeing method is a potential alternative to develop uniformly coloured photochromic textiles providing excellent photochromic performance with additional economic and environmental benefits.

The development and design of novel functional and smart textile materials such as textile sensors and multicolored systems based on photochromic dyes necessitate controls of color intensities, switching speeds, and material durability. Precise control and synchronization of dye kinetics are important for multi-colored photochromic applications especially. However, durability towards abrasion and washing should not be compromised on if we aim to design reliable future textile products. In this study, two different commercial photochromic dyes — a naphthopyran and a spirooxazine-based dye — have been applied on PET fabric by inkjet printing and UV-LED curing. The photochromic textiles’ color behavior, fastness to abrasion and washing, and handle are evaluated using spectrophotometry, scanning electron microscopy, and Kawabata evaluation system. Despite a decrease in color performance after washing, the photochromic inkjet print is effective and barely influences the textile structure. Reduced rigidity of the host matrix promoted higher color yields and faster dye kinetics, but also improved durability towards abrasion and washing. In order to synchronize kinetics of the different dye types for multi-colored applications, distinct curing conditions are preferable, which, however, result in varying print durability. In the design of multi-colored photochromic textiles, dye kinetics, and durability have to be balanced.

Photochromic textiles are of considerable interest for smart and functional textile applications due to their remarkable dynamic colour changing effect when irradiated with light of a certain wavelength. The use of resource efficient processes, such as digital inkjet printing and supercritical carbon dioxide (scCO₂) dyeing techniques enables an economic production of those high-end functional products with high material costs. In this study, photochromic polyester fabric has been prepared by applying two commercially important photochromic dyes from spirooxazine (SO) and naphthopyran (NP) dye classes using scCO₂-dyeing technique. The properties of scCO₂ dyed photochromic fabrics were compared with the properties of the same dyes in a non-polar solvent, hexane. UV-Vis spectroscopy and a specially designed online colour measurement system capable of simultaneous UV irradiation and colour measurement were used to evaluate the photochromic colour behaviour. Both photochromic dye types embedded in textile as well as in solution showed significant reversible colour changing properties when exposed to UV light and revert to their original non-coloured form when the UV light is removed. The scCO₂ dyed polyester fabrics exhibited similar trends of colour build-up as in solution, while contrasting behaviour was observed in terms of colour changing rates compared to their behaviour in solution.

The complexity and challenges of higher education (HE) in recent times have been widely discussed in HE literature, as have concomitant demands on university teachers and their professional learning needs. Much attention has been paid to new academics in these conversations, but less so to international PhD and post-doctoral researchers, who are often asked to teach, yet can be precluded from attending foundational pedagogical courses. This paper discusses an interpretive-hermeneutic study based on a pedagogical course developed for new academics in this very situation. Our discussion focuses on professional growth experienced by the course participants in terms of pedagogical understanding and self-confidence, and what enabled that growth from the participants’ perspectives. On the basis of analysis of interviews, questionnaires and qualitative course evaluations, we consider the value of such purpose-built courses and offer insights into what may need to be considered by course developers to ensure that their impact is optimal.

In our research group focusing on resource efficient processes, we explore the waterless supercritical carbon dioxide (SC-CO₂) technology as a promising sustainable alternative to the traditional textile wet dyeing and water based finishing processes. Already, it is industrially implemented for textile dyeing, in particular for synthetic fabrics, and, being a dry color process it is regarded as only using ¼ of the physical footprint compared to conventional dyeing. This, does not only account for water and energy savings, but also includes advantages such as reduced emissions of harmful effluents, less amount of used dye, no or minimal use of auxiliaries (dispersing agents, carriers and surfactants) and low waste of material. To expand the industrial capabilities of this technology and open up for new business opportunities, our research focuses on textile functionalization in SC-CO₂, either by only applying a functional material or to combine dyeing and functionalization of fabric in a single-step process. For polyethylene terephthalate (PET) fabric dyeing (step 1) and functionalization (step 2) in a sequential process where similar processing parameters (high temperature and pressure) was used, it was found that the color was extracted in the second step. The PET dyeing kinetics using SC-CO₂ as a solvent depend on the transition in the amorphous regions of the fiber and diffusion properties and solvating power of the SC-CO₂ with the dye. Hence, extensive studies on compatibility between fiber, dye and functional compounds include solubility of dye and functional material in SC-CO₂, optimization of process parameters (pressure and temperature) and depressurization. This is crucial for understanding the adhesion mechanism between fiber and chemicals, and, particularly for a proper adhesion with a durable functional performance. Furthermore, as SC-CO₂ is a good solvent for hydrophobic compounds, nonionics and organic compounds with low molecules weight, there are challenges in modifying conventional compound or using co-solvents. Activities within this domain in our research group stretch between dyeing and functionalization of textiles with end-use properties such as antimicrobial, photochromic, moisture management, water repellency, soil repellency and flame retardant.

Digital inkjet printing is a production technology with high potential in resource efficient processes, which features both flexibility and productivity. In this research, waterborne, fluorocarbon-free ink containing polysiloxane in the form of micro-emulsion is formulated for the application of water-repellent sports- and work wear. The physicochemical properties of the ink such as surface tension, rheological properties and particle size are characterized, and thereafter inkjet printed as solid square pattern (10 × 10 cm) on polyester and polyamide 66 fabrics. The water contact angle (WCA) of the functional surfaces is increased from < 90° to ca. 140° after 10 inkjet printing passes. Moreover, the functional surface shows resistance to wash and abrasion. The WCA of functional surfaces is between 130° and 140° after 10 wash cycles, and is ca. 140° after 20000 revolutions of rubbing. The differences in construction of the textile as well as ink–filament interaction attribute to the different transportation behaviors of the ink on the textile, reflected in the durability of the functional layer on the textile. The functionalized textile preserves its key textile feature such as softness and breathability. Inkjet printing shows large potential in high-end applications such as customized functionalization of textiles in the domain of smart textiles.