Molecular Sensing by Nanoporous Crystalline Polymers

Abstract

Chemical sensors are generally based on the integration of suitable sensitive layers and transducing mechanisms. Although inorganic porous materials can be effective, there is significant interest in the use of polymeric materials because of their easy fabrication process, lower costs and mechanical flexibility. However, porous polymeric absorbents are generally amorphous and hence present poor molecular selectivity and undesired changes of mechanical properties as a consequence of large analyte uptake. In this contribution the structure, properties and some possible applications of sensing polymeric films based on nanoporous crystalline phases, which exhibit all identical nanopores, will be reviewed. The main advantages of crystalline nanoporous polymeric materials with respect to their amorphous counterparts are, besides a higher selectivity, the ability to maintain their physical state as well as geometry, even after large guest uptake (up to 10–15 wt%), and the possibility to control guest diffusivity by controlling the orientation of the host polymeric crystalline phase. The final section of the review also describes the ability of suitable polymeric films to act as chirality sensors, i.e., to sense and memorize the presence of non-racemic volatile organic compounds.

Nanoporous polymeric materials: A new class of materials with enhanced properties

“…These materials can detect organic compounds or low-molecular-mass substances present in gaseous and liquid environments. For instance, Pilla et al [211] showed how 1-lm-thick s-PS films (porosity: 7%; pore size: not specified) can work as gravimetric sensors for the detection of chloroform in both vapor and liquid phases.…”

Factors controlling the structure of syndiotactic polystyrene upon the guest exchange and guest extraction processes

“…These nanoporous crystalline forms were found to have the capability to absorb molecules like CO 2 and H 2 [44,45] as well as organic molecules [16,46]. Hence, these materials can be used as sensors, [47][48][49][50] molecular sieves, [46,[51][52][53], catalysts [54], etc.…”

Microporous-crystalline microfibers by eco-friendly guests: An efficient tool for sorption of volatile organic pollutants

“…These microporous-crystalline polymers are able to absorb volatile organic compounds (VOC) also when present in traces and have been mainly proposed for molecular separation [22][23][24][25][26][27], sensor [28] and catalysis [29][30][31] applications. In particular two different microporous crystalline forms, named δ [10-13, 16, 17] and ε [14], have been thoroughly described for s-PS.…”