Sealant compositions comprising an alkali swellable latex and a pH increasing material and methods of using the same to service a wellbore are provided. In one embodiment, the sealant composition can be used in a wellbore and includes an alkali swellable latex and a pH increasing material. The sealant composition can have a pH of from about 7 to about 14. In other embodiments, the pH increasing material includes a base-producing material. The base-producing material can include alkali and alkali earth metal carbonates, alkali and alkali earth metal bicarbonates, alkali and alkali earth metal hydroxides, alkali and alkali earth metal oxides, alkali and alkali earth metal phosphates, alkali and alkali earth metal hydrogen phosphates, alkali and alkaline earth metal sulphides, alkali and alkaline earth metal salts of silicates, alkali and alkaline earth metal salts of aluminates, water soluble or water dispersible organic amines, polymeric amine, amino alcohols, or combinations thereof.