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Background matching, a form of camouflage, involves species developing patterns and coloration that closely resemble their environment. Humans have utilized camouflage and background matching, particularly in military applications, to reduce detectable characteristics, known as signatures. Recent advancements in sensor systems necessitate the development of effective camouflage in the short-wave infrared (SWIR) range (0.9 – 2.5 µm). However, absorption of SWIR radiation is heavily influenced by water, and dry textile materials may be easily detectable against a forest background due to their low water content. To address this challenge, this master's thesis explores the integration of hydration onto a textile fabric to reduce the signature in SWIR. Various fabric types were included in this study. The optical properties of these textiles, both when wet and dry, were evaluated using SWIR imaging and UV-VIS-NIR spectroscopy, and compared to foliage. Surface modifications were employed to introduce hydrophobic properties to the fabric, such as the application of water-repelling agents (Nikwax and OrganoTex) or functionalized silica nanoparticles. The water evaporation rates of untreated and surface-treated fabrics were assessed. However, the hydrophobic surface did not significantly reduce water evaporation from the fabrics. Similarly, the addition of a nanocellulose-based hydrogel on the fabric surface did not result in a significant change in evaporation. Combining the hydrogel with water-repelling solutions in a multilayer configuration indicated prolonged evaporation, but further tests are required to validate this finding. This master's thesis demonstrates that introducing water into a dry textile fabric alters its spectral properties, making it more similar to foliage. However, the primary challenge lies in retaining water within the material for improved camouflage in SWIR wavelengths.

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Modern firefighter protective equipment is excellent at protecting firefighters from surrounding heat, but how effective is at deflecting incoming radiant heat, and would the use of more reflective textiles, be able to further increase the equipment’s protective properties? This study aims to understand the different properties that reflective materials, compared to standard firefighter outer layers, have against radiative heat flux. The textiles of firefighter turnout gear and the reflective textiles used in the smelting industry have been examined when exposed to varying levels of radiant heat in a cone calorimeter. The materials were examined before and after a layer of soot was applied to them, to understand their capabilities if used in a soot-rich environment. The change in material emissivity, when soot was applied, could then be calculated for each material. The heat reducing properties of the sooted and non sooted materials emissivities were tested, using computer simulations of a firefighter’s full turnout gear. First the radiative and convective heat fluxes were compared within a computational fluid dynamics software called FDS, second the skin level temperature was calculated using VGP, a finite element software that accounts for heat flow further into the skin and body.  During the experiment it was found that the emissivity of the reflective material even after soot application, performed better than that of the standard firefighter gear. In the simulations, the sooted reflective material emissivity would reduce the total heat flux to the firefighter with an average of 19% compared to the sooted standard turnout gear. Using the temperature of 44 °C as the limit for human skin damage, the use of a reflective emissivity would allow a 19% longer exposure to the same incident heat before possible skin damage would occur. Reducing the emissivity of current turnout gear would prove valuable as a method of reducing heat accumulation in a firefighter, especially at key areas more susceptible to the radiative heat flux from smoke-layers and radiative flames. This would in turn provide safer work environments for structural firefighting by reducing heat stress during active operations.

This paper is about MusiCushions: Interactive cushions to control external speakers in a living room. The interactive cushions are made of smart and interactive textiles, which acceptance has been profoundly investigated. Several studies have come to the conclusion that the most important feature for acceptance of smart and interactive textiles is the aesthetics of the textile interface. Therefore, this study investigates the question: How is integration of interactive cushions in the home environment affected by design concepts with different levels of explicit interaction and types of use cues? The method used in this study is based on constructive design research (CDR), where the design process consisted of moodboarding, sketching, prototyping and evaluation. Three prototypes were built and tested in two different user observations. The interactive cushions were considered well integrated in the home environment but there is room for improvement of usability. The evaluation showed that visual cues were the most important feature for usability but that there is a trade off between use cues and aesthetics. / Denna studie handlar om MusiCushions: Interaktiva kuddar att kontrollera externa högtalare med i ett vardagsrum. De interaktiva kuddarna är gjorda av smarta och interaktiva textilier, vars acceptans har varit grundligt utforskad i tidigare studier. Flera studier visar att den viktigaste faktorn för acceptans av smarta och interaktia textilier är estetiken av ett textilt gränssnitt. Därför undersöker denna studie frågan: Hur är integrering av interaktiva kuddar i hemmet påverkad av design koncept med olika nivåer av explicit interaktion och typer av use cues? Metoden som denna studie är baserad på är "Constructive design research" (CDR) och design processen bestod av utformande av moodboards, sketcher, prototyper och utvärdering. Tre prototyper var utvecklade och testade i två olika användarobservationer. De interaktiva kuddarna ansågs vara väl integrereade i hemmet, men det finns utrymme för användbarheten att förbättras. Utvärderingen visade också att visuella use cues var den viktigaste faktorn för användbarhet, men att det måste göras en avvägning mellan use cues och estetik då den ena påverkar den andra.

Electrically conductive fabrics are one of the major components of smart textile that attracts a lot of attention by the energy, medical, sports and military industry. The principal contributors to the conductivity of the smart textiles are the intrinsic properties of the fiber, functionalization by the addition of conductive particles and the architecture of fibers. In this study, intrinsic properties of non-woven carbon fabric derived from a novel linear lignin, poly-(caffeyl alcohol) (PCFA) discovered in the seeds of the vanilla orchid (Vanilla planifolia) was investigated. In contrast to all known lignins which comprise of polyaromatic networks, the PCFA lignin is a linear polymer. The non-woven fabric was prepared using electrospinning technique, which follows by stabilization and carbonization steps. Results from Raman spectroscopy indicate higher graphitic structure for PCFA carbon as compared to the Kraft lignin, as seen from G/D ratios of 1.92 vs 1.15 which was supported by a high percentage of graphitic (C-C) bond observed from X-ray photoelectron spectroscopy (XPS). Moreover, from the XRD and TEM a larger crystal size (Lc=12.2 nm) for the PCFA fiber was obtained which correlates to the higher modulus and conductivity of the fiber. These plant-sourced carbon fabrics have a valuable impact on zero carbon footprint materials. In order to improve the strength and flexibility of the non-woven carbon fabric, lignin was blended with the synthetic polymer Poly acrylonitrile (PAN) in different concertation, resulting in electrical conductivity up to (7.7 S/cm) on blend composition which is enough for sensing and EMI shielding applications. Next, the design of experiments approach was used to identify the contribution of the carbonization parameters on the conductivity of the fabrics and architecture of the fibers, results show carbonization temperature as the major contributing factor to the conductivity of non-woven fabric. Finally, a manufacturing procedure was develop inspired by the architecture of plant fibers to induce controlled porosity either on the skin or core of fibers which results in stiffness and flexibility in the fibers. Coaxial Electrospinning and Physical foaming (CO2 foaming) techniques were utilized to create the hierarchical fiber architecture. Finite Element model was developed to design for mechanical properties of the bioinspired fiber mesh. Results show the polymers contributes less in a coaxial design as compared to the individual fibers for mechanical properties. This manufacturing method can use for hierarchical functionalization of fibers by adding conductive nanoparticles at different levels of fiber cross-section utilized for sensing applications in sports and medical industry.

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