Neutral, π-Radical-Conjugated Microporous Polymer Films of Nanoscale Thickness for Potential Use in Magnetoelectronics and Sensor Devices

π-Radical conjugated microporous polymers (CMPs) are highly appealing for optoelectronics, especially optical response-based sensor devices, and their thin film fabrication is demanding for developing functional devices. Toward this, neutral, π-radicalic CMP films (poly-D•, poly-T•: SBET-488 m2/g) of nanometer thickness (24, 33 nm) were fabricated from air stable, radicalic carbazole-substituted polychlorotriphenyl methane (PTM) radical monomers using electropolymerization method. Electron paramagnetic resonance spectra with g value of 2.0029 revealed radical nature of monomers, polymer thin films. The monomers in solution and polymer thin films are reversibly reduced electrochemically as observed by cyclic voltammetry measurements. The radicalic CMP films (poly-T•, poly-D•) displayed intervalence charge-transfer (IV-CT) transition at ∼750 nm, which was not observed in their hydrogenated polymer films (poly-TH; SBET-385 m2/g, poly-DH). Poly-T• and poly-D• (both of yellow color) easily undergo a reductive conversion into anionic poly-T– and poly-D– (both of deep blue color) by simply being immersed into a n-Bu4NOH solution. All the properties of thin films are also compared with the chemically synthesized bulk hydrogenated (bulk-poly-TH) and radicalic polymer (bulk-poly-T•) powders. Our results demonstrate the designed synthesis of carbazolic radical monomers and utility of electropolymerization method to achieve π-radical CMP thin films for potential application in magnetoelectronics and sensor devices.