Disclosed are compositions and methods for treating and modifying surfaces and for enhancing delivery of active agents to surfaces treated therewith, wherein the compositions comprise siloxane polymers functionalized with pendant moieties comprising two or more anionic groups, at least one anionic group being a carboxy group. When applied to a suitable surface, the present composition forms a substantially hydrophobic coating of the anionic functionalized siloxane polymer on the treated surface. These polymers effectively deposit on surfaces that have cationic sites, which are capable of forming bonds or linkages with the anionic groups of the polymer. The treated surface becomes hydrophobic due to the deposition of the anionic functionalized siloxane polymer, which then imparts a variety of end use benefits to that surface such as ease of cleaning, soil release, stain removal and prevention, conditioning, etc. The anionic functionalized siloxane polymer further acts as a carrier to deposit active agents onto the surface and to improve retention and efficacy of the active agents on the treated surface. The present compositions are useful in a variety of applications including oral care, hair and skin care, personal care, cosmetics, and fabric and hard surface cleaning and conditioning.