When it comes to smart clothes, especially protective technical fabrics, the market is ripe with opportunity. Functional textiles produced for purposes other than aesthetics include antibacterial, superhydrophobic, and flame retardant materials. This kind of material is also known as "smart textiles" since it may change color or luminescence properties in response to external stimuli. Having long-lasting phosphorescence in textiles that light up in the dark is desired [1, 2]. Light is absorbed into the crystals of phosphorescence substances. The trap component in the phosphorescence compound then collects the light energy. Eventually, the photons of light that were trapped are released from the traps . Strontium aluminates that are activated by rare earth elements have been employed in a number of applications, including emergency signs, safety textiles and photochromic ink . Several phosphorescent pigments have been described with their ability to develop a wide range of products with various emission colors, such as the greenish emission from SrAl2O4:Eu2+,Dy3+ ; bluish emission from CaAl2O4:Eu2+,Nd3+ ; and red emission from Y2O2S:Eu3+,Mg2+,Ti4+ . As a result of its high quantum efficiency, high recyclability, nonradioactivity, and good thermal, chemical and photostability, LSAO has long been considered a key long-lasting phosphor [8–10]. Hydrophobic surfaces could be created using a variety of techniques, including nanofibers, chemical etching, plasma, sol-gel, and lithography. However, those techniques have demonstrated difficulties such as slow and hard processing, and the requirements of trained personnel and sophisticated instruments . Using the pad dry curing procedure to coat fabrics is a straightforward and cost-effective way to make useful outerwear. In transportation and packing, textiles' hydrophilicity tends to restrict their utility. Static contact angle of > 150° and sliding angle of < 10° are required for superhydrophobic materials [12, 13]. As a result, corrosion prevention, maritime industry, antifouling, and oil-water separation have all profited from the usage of superhydrophobic materials . Using micro/nanoscale hierarchical materials, hydrophobic substrates with high surface roughness have been developed. Fluorine-based chemicals have been utilized to make hydrophobic materials. These compounds, on the other hand, have been proved to be costly and dangerous [15–17]. In recent years, the emphasis of research has shifted to environmentally benign compounds for superhydrophobic materials. Using a butynorate catalyst to ambient temperature vulcanize silicone rubber is an environmentally friendly polymerization. Chemical, heat, and age resistance are just a few of the properties of silicone rubber. Typical properties of silicone rubber include a low viscosity, high hardness, and low shrinking. It is utilized in aircraft, 3D printing, optics, and electronics [18–21].
Flame retardant treatment could be applied to flammable materials in order to limit the potential for damage caused by burning. Firefighters could slow and restrict the blazing process to perform rescue operations and help persons trapped in wildfires escape . Different chemical agents have been developed to improve the resistance to flames in various products. Halogen-containing fire-retardant chemical agents have been demonstrated to emit poisonous gases  despite their widespread usage. Inorganic boron-containing flame retardants are not producible industrially because their matrices do not have sufficient binding ability. Phosphorus-bearing flame retardants, on the other hand, have long been acknowledged as environmentally friendly. In compliance with environmental regulations, phosphorus-based flame retardant chemicals create no toxic substances during the blazing process [24, 25]. The flame retardant performance could be improved by loading two or more types of organic-based phosphorus and nitrogen/phosphorus derived components into a product matrix. Fibers made of linen are more durable, have lower heat conductivity, are more absorbent, and dry faster than fibers made of cotton. Towels, napkins, tablecloths, and chair coverings are just some of many linen-based goods on today’s market. Until recently, linen was a cheap and plentiful commodity . Compared to cotton fibers, it has a longer staple length. Because of its durable nature and low allergenic potential, linen is now one of the most popular fabrics for bed linens. Despite this, linen substrates have been limited in their application due to their intrinsic flammability, low water resistance, and microbial invasion . When immobilizing superhydrophobic and photoluminescence agents into textile material, a variety of useful products for both garments as well as high-performance applications could be produced . According to literature, linen goods with photoluminescence, superhydrophobic, and fire-resistant properties have not been documented yet [29, 30]. It is possible to maintain the flame-retardant performance of linen for a longer time periods by imparting hydrophobicity to the treated linen, which allows linen to provide an improved protection value. Thus, photoluminescence, superhydrophobicity, and fire-resistant properties could be combined to boost the durability of the treated linen fabrics.
Herein, we describe the production of superhydrophobic, flame retardant and photoluminescent linen fabrics using the pad dry curing technology. Ammonium polyphosphate, LSAO nanoparticles, and silicone rubber were admixed together to provide a nanocomposite coating film for linen. Throughout the burning test, the as-coated linen fibers demonstrated superhydrophobic and photoluminescent properties, as well as the capacity to form a char layer during the burning period, exhibiting self-extinguishing qualities. After 24 washing cycles, the treated linen samples retain their self-extinguishing qualities. LSAO was employed as a photoluminescent agent, silicone rubber was employed as a superhydrophobic and crosslinking agent, and ammonium polyphosphate was used as the flame-retardant compound. The shape and diameter of the nanoscale pigment particles were inspected using TEM. The morphology and elemental contents of cured linen were studied using XRF, EDX, SEM, and FTIR. Significant differences in the characteristics of the treated linen substrates could be attributed to the quantity of LSAO nanoparticles. The water-repellent properties of the phosphor nanopowder were improved by increasing the quantity of LSAO nanopowder. The luminescence properties of the cured linen were evaluated using excitation, emission, decaying, and lifetime spectra. Comfort was evaluated by taking measurements of bend length and air permeability. Textiles could be finished using the current approach on a large scale without the need for costly technology, making it suited to mass-produce multiple-purpose clothes.