Alcohol sensing and classification using PCF-based sensor

Designing hollow-core PCF sensors for high-performance terahertz detection of NaCN and KCN

Cyanide is very poisonous and raises environmental problems because of its industrial application and potential as a terrorist weapon. Given CN's toxicity and possible hazard to people, an effective and adaptive detection approach is needed. This specification suggests using a PCF to build a terahertz Hexagonal Core and Curved rectangular air holes sensor to detect NaCN and KCN. The recently created PCF analysis, which was promptly delivered, reveals an RS concentration of 99.62 % for NaCN and a maximum concentration of KCN is 99.08 %. In addition, we analyzed the Confinement Loss (CL) at a value of 5.88 × 10-09 dB/m and 2.07 × 10-05 dB/m, as well as EML at values of 0.0020 cm-1 and 0.0026 cm-1, accordingly, about these hazardous substances. The designed detector can identify NaCN and KCN at low concentrations even with small RI shifts due to its high sensitivity. Real-time NaCN and KCN detection and monitoring through nerve reflexes is essential for life-threatening conditions. It can selectively work in NaCN and KCN, ensuring accurate detection even in complex chemical compositions. Additionally, its tiny size allows for emergency use.

Unveiling the potential of polymer cholesteric liquid crystal interpenetrating networks as a label-free alcohol biochemical sensor

In this study, an optical sensor is developed, incorporating hydrogen-bonded photonic array dots containing poly(acrylic acid) (PAA) within a polymer cholesteric liquid crystal interpenetrating polymer network (PCLCIPN) framework, thereby effectively controlling porosity. This methodology involves the fabrication of a porous photonic film, subsequent infusion with a hydrogel (PAA), and precise UV-curing to generate patterned array dots. The sensor exhibits exceptional discriminatory capability between methanol and ethanol, accurately discerning their varying concentrations within alcohol solutions. The optical sensing performance of the film is rigorously evaluated through continuous monitoring of wavelength shifts in the transmission spectrum across various alcohol concentrations. Notably, the observed wavelength shifts demonstrate a linear correlation with the concentration of alcohol, thereby enabling precise quantitative analysis of the alcohol solutions. The sensor exhibits a sensitivity of 0.44 nm/% for ethanol concentrations ranging from 5% to 60%, increasing to 2.1 nm/% for concentrations between 60% and 80%. Similarly, for methanol, sensitivities of 0.68 nm/% (5-60%) and 2.2 nm/% (60-80%) are recorded. Remarkably, this sensitivity trend extends seamlessly to 1 : 1 ethanol/methanol ratios, with values of 0.49 nm/% (5-60%) and 2.25 nm/% (60-80%). Furthermore, these sensors demonstrate colorimetric response to different alcohols, rendering them accessible and cost-effective biosensors for visual detection, thus obviating the necessity for complex analytical instruments.

Alcohol Selective Optical Sensor Based on Porous Cholesteric Liquid Crystal Polymer Networks

A responsive hydrogen-bonded cholesteric liquid crystal polymer (CLCP) film with controlled porosity was fabricated as an optical sensor to distinguish between methanol and ethanol in alcohol solutions. To facilitate responding the alcohols, porosity was generated by removing the nonreactive liquid crystal agent, and the hydrogen bridges of CLCP were broken. The sensitivities of CLCPs to ethanol and methanol were obtained by monitoring the wavelength shifts of the transmission spectrum at different alcohol concentrations and ratios of methanol/ethanol. Changes in the central wavelength of the CLCP network transmission spectrum allowed the methanol–ethanol ratio to be discriminated. A linear relationship between wavelength shift of CLCP networks and alcohol concentration was obtained experimentally, and the sensor characteristics were explored. The sensitivities of the CLCPs were 1.35 and 0.18 nm/% to ethanol and methanol, respectively. The sensing sensitivity of cholesteric networks to alcohol molecules increased as the methanol–ethanol ratio declined. Therefore, CLCP could act as a stimuli-responsive material to distinguish the concentrations of acetone and ethanol in mixed solutions. Furthermore, the impact of UV intensity for curing a CLC mixture on the sensing sensitivity to the different alcohol concentrations was also studied. The higher UV intensity could enhance the sensitivity to alcohol molecules and distinguishing ability between methanol and ethanol.