Transition temperature control of adsorption–desorption property of PNIPAM / mesoporous silica composite by addition of crosslinking agent

The aim of this study was to clarify the influence of the crosslinking agent N, N′- methylenebisacrylamide (BIS) on the structural and adsorption–desorption properties of a poly(N-isopropylacrylamide) (PNIPAM)/mesoporous silica composite. CHN elemental analysis, X-ray diffraction, Fourier-transform infrared spectroscopy, nitrogen adsorption, and thermogravimetric studies revealed that the temperature-responsive composite had the MCM41-type hexagonal structure and that the addition of PNIPAM and BIS hardly affected the structure of the mesoporous silica. The transition temperature, defined as the temperature at which the amount of adsorption of methyl orange ions changed drastically, shifted to higher temperatures upon the addition of BIS to the PNIPAM (from 30–35 °C for PNIPAM without BIS to 35–40 °C for PNIPAM with BIS).

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► PNIPAM with BIS / mesoporous silica composite was synthesized.
► PNIPAM was present as a thin layer on the external surface of mesoporous silica.
► Transition temperature depended on the amount of BIS added.