Calixarene functionalization of TiO2 nanoarrays: an effective strategy for enhancing the sensor versatility

Abstract

Sensitive, selective, low-cost, and simply designed sensors for gases and analytes are highly attractive. The rational synergy between calixarenes (CAs) and titania nanorods (TiO₂NRs) and nanotubes (TiO₂NTs) gives rise to completely new types of behaviors that open unprecedented applications. First, the geometric building of NRs and NTs leads to excellent signal amplification and transduction. Second, grafted CAs create self-assembled monolayers (SAMs) that switch order under a thermal stimulus and generate a stimuli-responsive behavior, thus promoting modulated sensing properties. Third, CAs accelerate gas diffusion in the sensor, yielding a fast, sensitive, selective, and reproducible response to H₂ at room temperature (RT). In addition, these systems may act as sensors for other analytes, such as the pesticide profenofos (PFF).