The present invention relates to a composition comprising a binder comprising one or more siloxane polymers, silicone resins, silicone based elastomers, and mixtures thereof, wherein said binder optionally comprises one or more cross-linker components comprising a silane and/or a siloxane containing silicon-bonded hydrolysable groups; and a hydrophilic powder and/or gel selected from one or more amorphous, porous hydrophilic silica(s), one or more hydrophilic silica aerogel(s) and mixtures thereof, said amorphous, porous hydrophilic silica and/or said hydrophilic silica aerogel having a BET surface area from 100 m