Calixarene-based cryopolymers: a versatile smart materials platform suitable for both air and water remediation

Environmental pollution caused by the release of hazardous chemicals into air and water poses serious risks to ecosystems, public health, and infrastructure. Addressing these challenges requires innovative materials capable of both detecting and removing diverse pollutants. However, most current materials are designed to target either air or water pollutants, leaving a gap in multifunctional solutions. This study presents a pioneering approach to bridge this gap by introducing two novel calixarene-based cryopolymers, combining the macroporous structure of cryogels with the recognition capabilities of calixarenes. The synthesized materials were found to be valuable tools for detecting and capturing pollutants in both air and water, taking advances from a dual mechanism of absorption: by chelation through the acidic functionality inserted on calixarene scaffold and by a host-guest complex formation with calixarene cavity through cation-π interactions. As an additional advantageous property, they have the ability to detect the presence of NO₂ in the air through an evident color change. These multifunctional materials represent a breakthrough in environmental remediation, offering a single platform for addressing pollutants in air and water, marking a step forward in pollution management technologies.