A new RRS method for measurement of temperature with magnetic-liquid crystal nanosurface molecularly imprinted polymer probe

Abstract

A new magnetic-liquid crystal nanosurface molecularly imprinted polymer (5CB-Fe₃O₄@MIP) resonance Rayleigh scattering temperature sensor was prepared, using liquid crystal 4′-cyano-4′-pentylbiphenyl as the temperature sensing element, nano-Fe₃O₄ as the substrate, methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the crosslinking agent. It was characterized by molecular spectroscopy, scanning electron microscopy and Fourier transform infrared spectroscopy. The thermosensitive effect of 11 liquid crystals, that is, the relationship between RRS and temperature, was studied. The 4′-cyano-4′-pentylbiphenyl exhibits best sensitive. The 5CB-Fe₃O₄@MIP temperature sensor had a strong resonance Rayleigh scattering peak at 370 nm. The resonance Rayleigh scattering intensity increased with the increase of temperature, and showed a good linear relationship. The temperature range of measurement was 30–95 °C, with a slope of 16.8 a.u./°C. And by optimizing the preparation conditions of molecularly imprinted polymers, the best preparation conditions were obtained: template molecule: 0.25 mmol, functional monomer: 2.5 mmol, cross-linker: 5 mmol, reaction temperature: 70 °C, reaction time: 2.5 h. As a comparison, we also studied the effect of Fe₃O₄ with different particle sizes on the 5CB-Fe₃O₄@MIP temperature sensor. At the same time, the temperature sensor is applied to the temperature measurement of cooling water, which is effective.