Silica suspensions

A suspension of silica particles comprising:

• a water-immiscible polar organic liquid,
• at least one phase transfer agent, and
• silica particles having an average particle size of less than 400 nm, characterised in that organosilane moieties derived from compounds of formula (I):
• R—Si(OR1)3 (I),
• wherein R is —CH3 or —CH═CH2 and each R1 is independently selected from the group consisting of —CH3 or —C2H5, are chemically bound to the silica.