A simple and inexpensive thermal optic nanosensor formed by triblock copolymer and polydiacetylene mixture

Exploring the Origins of Low-Temperature Thermochromism in Polydiacetylenes

This review article delves into the intriguing phenomenon of low-temperature thermochromism, whereby materials change color in response to temperature variations, with a particular focus on its applications in temperature-sensitive fields like medical storage. By closely examining thermochromic materials, this article highlights their potential to offer innovative solutions for monitoring and preserving thermolabile products that require strict temperature control. This leads to a special emphasis on polydiacetylenes (PDAs), a class of conjugated polymers with unique low-temperature thermochromic properties, positioning them as promising candidates for reliable temperature indicators. This article then explores the underlying mechanisms for fine-tuning the thermochromic behavior of PDAs, particularly discussing recent advancements in PDA design, such as structural alterations of monomers to achieve low-temperature thermochromism. These modifications, influenced by factors like side-chain length, hydrogen-bonding interactions, and the use of copolymers, are intended to result in irreversible color transitions at specific low temperatures, which is crucial to maintaining the integrity of thermally sensitive products. Finally, this article discusses the potential applications of PDAs as thermochromic sensors in tissue biobanking, where their ability to provide visual indications of temperature fluctuations could significantly enhance the monitoring and management of biological samples.

An optical sensor for the detection and quantification of lidocaine in cocaine samples

An optical sensor (OS) was synthesized by mixing 10,12-pentacosadiinoic acid (PDA) with a triblock copolymer for use in the detection/quantification of lidocaine (LD) in seized cocaine hydrochloride (seized CH) samples. In the presence of LD, the OS presented a chromatic transition from blue to red, while no chromatic transition was observed for other typical cocaine adulterants or cocaine hydrochloride. Isothermal titration calorimetry analysis revealed specific interactions between the PDA molecules of the OS and the LD molecules, with these interactions being enthalpically favorable (-1.20 to -36.7 kJ mol^-1). Therefore, the OS color change only occurred when LD was present in the sample, making the OS selective for LD. Consequently, LD was successfully detected in seized CH samples, irrespective of the type of adulteration. The OS was used for the quantification of LD in seized CH samples containing different adulterants, providing a linear range of 0.0959 to 0.225% (w/w), a precision of 7.2%, an accuracy ranging from -10 to 10%, and limits of detection and quantification of 0.0110% (w/w) and 0.0334% (w/w), respectively.