Fire-resistant, fire retardant and/or thermal insulation

A method of making a material, comprising:

• i) providing, using a sol-gel process using a gelation solvent, an open cell foam comprising a network of open pores or cells with at least some interior pores or cells in the network being accessible by a gas or liquid through at least some surface pores or cells in the network, wherein the sol-gel process is performed such that the gelation solvent remains in at least some of the open pores or cells;
• wherein the at least some interior pores or cells are within an interior portion of the open cell foam and the at least some surface pores or cells are positioned at one or more external surfaces of the open cell foam, and the at least some interior pores or cells and the at least some surface pores or cells comprise pore or cell walls defining a pore or cell;
• ii) exchanging, by solvent exchange, the gelation solvent with a miscible solvent or solvent mixture in which one or more phase change materials (PCMs) are soluble;
• iii) exchanging, by solvent exchange, the miscible solvent or solvent mixture with a miscible solvent or solvent mixture comprising the one or more PCMs such that the one or more PCMs infiltrate the at least some of the open pores or cells;
• iv) exchanging, by solvent exchange, the solvent or solvent mixture comprising the one or more PCMs with a solvent or solvent mixture in which the one or more PCMs are not soluble such that the one or more PCMs are deposited in or adjacent to at least some portions of at least some of the pore or cell walls of both the at least some surface pores or cells and the at least some interior pores or cells;
• v) exchanging, by solvent exchange, the solvent or solvent mixture in which the one or more PCMs are not soluble with a drying solvent;
• and
• vi) removing the drying solvent from the open cell foam by evaporation at ambient temperature and pressure so as to leave the one or more PCMs deposited on or adjacent to the at least portions of the pore or cell walls of a plurality of pores or cells of the network;
• wherein the one or more PCMs is or are hydrated inorganic materials and is or are deposited in 50-100% of the at least some surface pores or cells and the at least some interior pores or cells in the network, and wherein the one or more PCMs fills 1-25% of a volume of either or both of the at least some surface pores or cells and the at least some interior pores or cells.