A multifunctional material composition functioning as a halogen-free flame-retardant finish combined with in certain implementations one or both of antimicrobial and insect-repellant is nanomanufactured by the absorption/adsorption of metallic salts with one or more additional compounds by inorganic crystallites. The identity of the additional compounds is determined by the desired functionality of the substrate. The material composition can be chemically and mechanically applied to substrates (e.g. to cotton, nylon, and polyester based textile fabrics), for example, to yield durable antimicrobial, insecticidal, and environmentally friendly flame retardant materials. The addition of nano-scale metallic deposits to a phosphorous-rich and nitrogen-rich architecture complex improves the flame retardant properties of the substrates.