Sol-gel technique for protective textile and clothing

If not inherently flame retardant, most of either natural or synthetic fibers and fabrics easily burn when put in contact with a flame or exposed to an irradiative heat source: this unfavorable behavior remarkably restricts the potential applications of these materials, particularly referring to those uses, for which flame retardance is definitely mandatory. Therefore, it becomes very important to protect the fibers and fabrics from the action of fire: in this context, apart from the possibility of embedding specific additives (the so-called flame retardants) within synthetic textiles during their production, another opportunity involves surface engineering approaches. In particular, it is possible to design specific fully inorganic or hybrid organic-inorganic coatings, able to protect the underlying substrate from the action of fire. Among the possible surface engineering methods, the sol-gel process, born and well established for the synthesis of ceramic materials, is being utilized very frequently for conferring flame retardant properties to textiles. This chapter aims at summarizing the development and current state-of-the-art on the use of the sol-gel processes as efficient protective flame retardant finishing for textile materials. Furthermore, the still present limitations of this surface engineering approach will be considered, as well as its further potential future advances.