A　facile　grafting-onto　strategy　has　been　exploited　to　prepare　a　smart　pH-controlled　drug　delivery　system　(P-B)　via　surface-grafting　of　the　preformed　silane　modified　with　PMAA　[poly(methylacrylic　acid)]　onto　the　surface　of　BMMs　(bimodal　mesoporous　silicas).　Accordingly,　the　PMAA　acted　as　the　pH-sensitive　component,　and　the　silane　provided　an　anchor　with　the　surface　OH　group　of　BMMs.　Thereby,　a　series　of　P-B　with　different　mass　ratio　of　BMMs　to　PMAA　have　been　synthesized.　Meanwhile,　ibuprofen　(IBU)　was　applied　as　a　model　drug　to　investigate　the　influences　of　different　pH　values　on　drug　release.　The　results　showed　that　the　obtained　P-B　presented　a　flexible　control　over　drug　release　by　adjusting　the　grafted　amount　of　PMAA.　Moreover,　the　drug　release　amount　of　the　drug-loaded　samples　was　pH　dependent　and　increased　with　the　increasing　of　pH　value,　implying　that　the　P-B　are　promising　drug-carriers　in　application　of　pH-responsive　controlled　drug　delivery　systems.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.