# Metal-Organic Frameworks as Promising Textile Flame Retardants: Importance and Application Methods
## 5 Challenges and Future Perspectives  
In the textile industry, the durability of finishes is crucial, especially for advanced functionalities such as flame retardancy, antimicrobial properties, and controlled release. Recent research has focused on using metal-organic frameworks (MOFs) to achieve these functionalities. In addition to satisfying the functional requirements, the application of MOFs to textile substrates must ensure durability--a key aspect of textile quality. Researchers are exploring alternatives to enhance this durability, including structural modifications to the substrate or the MOF itself, and the use of cross-linking techniques. MOF-textile adhesion can occur either ex situ or in situ within cellulose-based textiles. The metal ions of MOFs coordinate with the hydroxyl groups of cellulose, which acts as a mixed ligand with an organic acid in the formation of MOFs [80; 87; 131; 132]. Modifyingcellulose can create chemical groups that serve as anchors for MOF adhesion, thereby increasing durability. [PERSON] and collaborators [5] developed a durable coating made of UiO-66, cationic starch (St), and polyphosphonitrile (PZS) on cotton fabrics modified with citric acid, without affecting the fabrics' color, whiteness, or stiffness. In in situ synthesis, [PERSON] and team [133] obtained a multifunctional fabric with visual aesthetics and washing durability through the carboxymethylylation of cotton fabrics--a strategy also employed by other researchers and substrates [81; 86; 134]. [PERSON] and collaborators [45] used a different MOF-textile adhesion method, developing coatings from UiO-66 decorated with spherical polypyrrole nanoparticles and wrapped with chitosan chains, achieving high flame retardancy, UV protection, and tensile strength. Another approach considered by research groups involves using cross-linking agents to promote more cohesive bonds between the metal-organic structures and textile substrates. [PERSON] and collaborators [135] reported using 3-glycidyloxypropyl-ltrimethylaxsilane as a bonding agent in natural cotton, viscose, and linen fibers to create functional fabrics. [PERSON] and colleagues [136] performed the in situ growth of ZIF-8 on cotton fibers at room temperature, followed by coating with polydimethylsiloxane (PDMS), ensuring the durability of superhydrophobic and antibacterial fabrics. [PERSON] [137] and his team used silicate as a cross-linker to produce durable functional fabrics with attention to coloration. Metal-organic structures can also act as adsorbents for dyes, improving durability. [PERSON] [101] demonstrated this by using cotton fabric to achieve dyeing with acid dyes. Beyond fixation properties, the colorimetric aspects of MOFs applied to textiles are also crucial due to their impact on the visual appearance of fabrics. MOFs can have intrinsic colors that vary depending on the metals and organic ligands used in their synthesis. Incorporating colored MOFs can alter the visual appearance of textiles, adding new shades [138; 139] or intensifying existing colors. For instance, [PERSON] [140] used ZIF-8 and colored nanospheres composed of polymethylhydrosiloxane (PMHS) through a spraying process to create multifunctional colored cotton fabrics. Typically, ZIF-8 and UiO-66 in powder form are white to slightly yellowish due to the synthesis reagents. [PERSON]'s [132] team reported the yellowing of cotton fabric after modification with UiO-66. ZIF-8, known for its white appearance, was chosen by [PERSON] [141] to modify cotton fabrics through acid dye adsorption. The colorimetric aspects of MOFs applied to textiles are complex and multifaceted. Researchers are exploring the intrinsic color of MOFs, the uniformity of application, and interaction with dyes to optimize the visual appearance of treated fabrics. Thus, while the application of MOFs to textiles can confer advanced functional properties, it must be carefully controlled to produce only the desired effects.