Interfacial polymerisation of anilinium at Langmuir monolayers

Abstract

Anilinium is strongly adsorbed at monolayers of the phospholipid L-alpha-dimyristoylphosphatidic acid (DMPA) and hexadecanesulfonic acid (HDSA) at the air-water interface, and undergoes chemical polymerisation under conditions where bulk polymerisation does not occur.

Two-Dimensional CVD-Graphene/Polyaniline Supercapacitors: Synthesis Strategy and Electrochemical Operation

“…For the low scan rate of 50 mV s –1 (Figure A), the pristine graphene exhibits an almost rectangular shape, whereas the graphene/polyaniline heterostructure shows prominent redox peaks with redox transitions located at around +0.25 and +0.40 V (RE: Ag/AgCl) for oxidation and at around +0.15 V for reduction, specifically the reduction of emeraldine to leucoemeraldine (see Figure C). This observation is in line with previously reported voltammetry data on polyaniline monolayers. ,, For the high scan rate of 500 mV s –1 , the pristine graphene voltammograms remained almost rectangular (Figure S3), while the graphene/polyaniline heterostructure exhibited less well-resolved redox peaks and a significant increase in current values (Figure S3).…”

“…No observation of polyaniline Raman signature outside the sulfonated graphene area (see Figure A) is consistent with the expectation coming from setting the reaction conditions for aniline polymerization, namely, that the polyaniline formation proceeds selectively on the acidic sulfonated surface under conditions applied . This conclusion on no formation of polyaniline outside the graphene area is also supported by the Raman maps (Figure B) showing the simultaneous absence (on the Si/SiO 2 wafer) and presence (on the graphene) of the Raman band of polyaniline located at ∼1165 cm –1 and the 2D mode of graphene.…”

“…First, CVD-graphene on a Si/SiO 2 wafer is functionalized by p -phenylene sulfonic groups using the diazonium protocol as previously reported . In the second step, an anilinium monolayer formed on the surface of the sulfonated graphene is oxidized by ammonium persulfate; this process is analogous to the synthesis of polyaniline monolayers from anilinium Langmuir–Blodgett films . The results of both synthetic steps are reflected by the Raman spectra of the nanomaterials (Figure A).…”

“…Various methods for producing polyaniline mono- and nanolayers have been reported: (1) self-assembly of the dissolved bulk polyaniline, − (2) electrochemical and chemical oxidative polymerization of anilinium films on self-assembled templates bearing sulfonic groups, , (3) synthesis of polyaniline thin films on substrate surfaces − and functionalized surfaces, − and (4) synthesis of polyaniline freestanding films utilizing templates or interfaces . Few of the above-mentioned methods work with surface sulfonation to produce an electrostatically stabilized anilinium monolayer for subsequent polymerization, , which is a concept easily transferable into graphene chemistry through graphene sulfonation. , …”

A comparative study of the electrodeposition of polyaniline from a protic ionic liquid, an aprotic ionic liquid and neutral aqueous solution using anilinium nitrate

“…15 The polymer film was smooth and not porous, which is not a desirable property for a supercapacitor device. 1,42 Other work has been carried out by Zhang et al 43 investigating the oxidation of anilinium in acidified aqueous media which allows for easier polymerisation.…”