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The purpose of this research is to ascertain the feasibility of fabricating polymer optical fibers (POFs) based textile structures by knitting with Polymethylmethacrylate (PMMA) based optical fibers for textile sensor application. It has long been established that by using the principles of physics, POFs have the capability to function as sensors, detecting strain, temperature and other variables. However, POF applications such as strain and pressure sensing using knitting techniques has since not been very successful due to a number of reasons. Commercially available PMMA-based optical fibers tend to be fragile and susceptible to breakages when subjected to stress during the knitting processes. Also light transmitted within these fibers is prone to leakage due to the curvature that results when optical fibers are interlaced or interlooped within fabric structures.

Using Stoll’s multi-gauge CMS 350 HP knitting machine, five fabric structures namely, 1 × 4 float knit structure, tunnel inlay knit structure, 3:1 fleece fabric and 2:1 fleece fabric structure respectively were used to knit sensor samples. The samples were subsequently tested for length of illumination and sensitivity relative to applied pressure.

The results of this preliminary study establish that embedding plastic optical fibers into a knitted structure during the fabric formation process for soft strain sensor application possible. The best illumination performance was recorded for tunnel inlay structure which had an average of 94 cm course length of POF being illuminated. Sensor sensitivity experiments also establish that the relative spectral intensity of the fiber is sensitive to both light and pressure. Problems encountered and recommendations for further research have also been discussed and proffered.

Due to resource limitations, an innovative technique (use of precision weight set) was used to apply pressure to the sensors. Consequently, information regarding the extent of corresponding sensor deformation has not been used in this initial analysis.

Because the fundamental step toward finding a solution to any engineering problem is the acquisition of reliable data, and considering the fact that most of the popular technologies used for soft textile sensors are still bedeviled with the problem of signal instability and noise, the success of this application thus has the tendency to promote the wide spread adoption of POF sensors for smart apparel applications.

As far as research on soft strain sensors is concerned, to the best of the authors’ knowledge, this is the first study to have attempted to knit deformable sensors using commercially available POFs.

Marine seaweeds, characterised by high-valued bioactive compounds, are used worldwide for several applications, including human food, animal feed, pharmaceutics and cosmetics, bioplastics, agricultural fertilisers, biofuels, and others. Seaweed production can be carried out through different approaches, from on-land or sea-based cultivation to the harvesting of wild stocks. The latter can be of particular importance in the case of seasonal algal over-proliferations, often caused by eutrophic conditions associated with intensive human industrial activities, and which wreak havoc with ecosystem functioning and hinder economic activities. In Europe, Italy experiences seaweed blooms in several coastal basins, such as the Lagoon of Venice and the Lagoon of Orbetello (Tuscany). Here, the proliferating seaweed represents a disturbance to the natural ecosystem and to local business and touristic activities. These biomasses hold no economic value in the country and are systemically removed and disposed of. Re-purposing the biomass to produce seaweed-derived commercial goods would provide benefits for the environment and local economic activities while promoting a sustainable business within a Circular Economy framework and contribute to the UN Sustainable Development Goals number 12 (‘Responsible consumption and production’), and number 14 (‘Life under water’), among others.