Polyelectrolyte/mesoporous silica hybrid materials for the high performance multiple-detection of pH value and temperature

Mesoporous silica nanoparticles have been widely adopted in energy, biology and medicine due to their well-ordered and stable structures. Nevertheless, few attempts have been made to study these materials as a sensing tool. Herein, we report a "smart" sensor for the dual-detection of the pH value and temperature, which was implemented with environmentally responsive polyelectrolyte/mesoporous silica electrodes. Using SBA-15 silica as the framework, we functionalized the internal mesopores with DMAMEA monomer via surface-initiated RAFT polymerization ("grafting-from" method). By controlling the degree of polymerization, the pore size and the specific surface area can be precisely controlled. When the degree of polymerization was optimized to 75, the hybrid material showed significant sensitivity in response to the pH value in the range of 4-10 and optimally responded to the temperature at 39 °C, setting a pH value of 10. The ionic conductivities of the template Fe(CN)₆^4-/3- and Ru(NH₃)₆^2+/3+ ions were switchable in different conditions. These results suggest that the polyelectrolyte/mesoporous silica hybrid materials could have potential for application in dual-functional sensors in environmental detection.