Rapid self-assembly preparation of p-nitrophenol-molecular imprinted photonic crystal sensors

To overcome the long period of three-dimension photonic crystal colloidal array preparation, a rapid self-assembly method is proposed. The effect of microspheres diameter and concentration, heating and nitrogen blowing have been also studied. According to the results, when the microspheres suspension concentration is 0.2 wt% and heating temperature of 70 °C, a highly regular 3D face-centered cubic colloidal crystal array structure self-assembles on the gas-liquid interface within 3 min. Then using this method, a p-nitrophenol-molecular (p-NP) imprinted photonic crystal sensor with high selectivity and sensitivity is prepared. The p-NP imprinted sensor presents twice signal intense than the non-imprinted sensor towards the target, and the structural color changes from blue to green. Meanwhile, the sensor responds in 3 min and can be reversible more than 9 times. This rapid self-assembly method provides a suitable way for large-area colloidal photonic crystal preparation with higher efficiency and good repeatability, which has a high value for practical applications.