Novel pillar[6]arene thin films for enhanced gas sensing of volatile organic compounds

On the surface of glass substrates, pillar[6]arene based compounds (I-P[6], R1-P[6], R2-P[6]), newly synthesized, were coated using the spin coating method, respectively. AFM, SEM-EDX, and contact angle measurements were applied to characterize the films. The thicknesses of the spun P[6]-based thin films were estimated using WINSPALL software. Based on experimental and fitting data, the thickness of the spun thin film was calculated to be 1.11 nm for I-P[6], 10.05 nm for R1-P[6], and 10.22 nm for R2-P[6]. These P[6]-based compounds were then used as a new gas sensing platform for the determination of various volatile organic compounds (VOCs). Due to the better interaction, the R1-P[6] coated film shows a higher sensitivity and better selectivity toward VOCs than that of I-P[6] and R2-P[6] films. Therefore, important sensor parameters such as response, sensitivity, limit of detection (LOD), limit of quantitation (LOQ), response time, and recovery time for the R1-P[6] thin-film sensor have been elucidated. The R1-P[6] thin film sensor performed better against dichloromethane than the other vapors tested with a sensitivity of 26.14×10–4 Hz/ppm, LOD and LOQ values of 1.26 ppm and 3.82 ppm respectively. This study presents a promising gas sensing platform for rapid and sensitive analysis of some industrial aliphatic hydrocarbons.