Electrogenerated Thin Films of Microporous Polymer Networks with Remarkably Increased Electrochemical Response to Nitroaromatic Analytes

Abstract

Thin films of microporous polymer networks (MPNs) have been generated by electrochemical polymerization of a series of multifunctional carbazole-based monomers. The microporous films show high Brunauer-Emmett-Teller (BET) surface areas up to 1300 m2 g(-1) as directly measured by krypton sorption experiments. A correlation between the number of polymerizable carbazole units of the monomer and the resulting surface area is observed. Electrochemical sensing experiments with 1,3,5-trinitrobenzene as prototypical nitroaromatic analyte demonstrate an up to 180 times increased current response of MPN-modified glassy carbon electrodes in relation to the nonmodified electrode. The phenomenon probably involves intermolecular interactions between the electron-poor nitroaromatic analytes and the electron-rich, high surface area microporous deposits, with the electrochemical reduction at the MPN-modified electrodes being an adsorption-controlled process for low scan rates. We expect a high application potential of such MPN-modified electrodes for boosting the sensitivity of electrochemical sensor devices.

Trends and challenges for microporous polymers

“…56,126 For the first reliable measurements of the surface areas of such films, which is hard to achieve as very low sample masses are naturally obtained, krypton sorption was used to determine a surface area of up to 1300 m 2 g À1 in a carbazole based CMP film, which compares nicely to the surface area found in a related bulk material. 126,127 These values could be even increased applying thiophene based monomers (42000 m 2 g À1 ). 31 Notably, the surface area of such films depends strongly on the solvents in which the electropolymerization is carried out.…”

“…nitrobenzene, dinitrotoluene and trinitrotoluene), showing a significantly increased current response or a quenched luminescence compared to a reference electrode without film deposition. 31,[126][127][128] Furthermore CMP thin films derived from dithiothiophene by electropolymerization could be reversibly oxidized and reduced, yielding a pronounced electrochromic effect.…”

Electrochemically Generated Thin Films of Microporous Polymer Networks: Synthesis, Properties, and Applications

“…Krypton and nitrogen adsorption isotherms of a) electrogenerated MPN films and b) corresponding bulk materials produced by oxidative coupling with FeCl 3 , respectively. Reproduced with permission . 2015, American Chemical Society.…”

“…a) Linear scan voltammograms (after background correction) for reduction of 0.5 μm aqueous 1,3,5‐trinitrobenzene (TNB) solution at P1 ‐modified or nonmodified (inset) glassy carbon electrodes (scan rate of 0.01 V s −1 ) and b) current ratio of the third reduction peak of TNB at MPN‐modified and nonmodified glassy carbon electrodes versus specific surface area of the MPN films. Adapted with permission . 2015, American Chemical Society.…”

Design of Open‐Shell π‐Conjugated Microporous Polymer Film with Super‐High Conductivity

“…Recently, scientists electrochemically generated thin films of microporous polymer networks. They used multifunctional carbazole‐ and thiophene‐based rigid monomers to build rigid 3D building blocks and obtained microporous polymer films with relatively smooth surface morphology . For example, Jiang and co‐workers designed thiophene‐based building blocks and used electropolymerization to form solution processable conjugated microporous polymer films, which can be used for device fabrications.…”