The phase behaviour in neutral and acid aqueous solution is reported for two poly(oxyethylene)/poly(oxybutylene)/(oxyethylene) (EBE) triblock copolymers, of composition E33B10E33 and E43B14E43. Micellar solutions of both copolymers were utilised for templated-silica synthesis under acidic conditions. Calcination of the silica products gave mesoporous materials. The E33B10E33-templated silica exhibited a spherical morphology, whilst the E43B14E43-templated silica comprised irregularly shaped particles.