AUTHOR=Mushtaq Irrum , Akhter Zareen , Shah Faiz Ullah 

TITLE=Tunable Self-Assembled Nanostructures of Electroactive PEGylated Tetra(Aniline) Based ABA Triblock Structures in Aqueous Medium

JOURNAL=Frontiers in Chemistry

VOLUME=7

YEAR=2019

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2019.00518

DOI=10.3389/fchem.2019.00518

ISSN=2296-2646

ABSTRACT=<p>PEGylated tetra(aniline) ABA triblock structure PEG-TANI-PEG (<bold>2</bold>) consisting of tetra(aniline) (TANI) and polyethylene glycol (PEG) was synthesized by coupling the tosylated-PEG to boc-protected NH<sub>2</sub>/NH<sub>2</sub> TANI (<bold>1</bold>) through a simple nucleophilic substitution reaction. Deprotection of <bold>2</bold> resulted in a leucoemeraldine base state of TANI (<bold>2</bold>-LEB), which was oxidized to stable emeraldine base (<bold>2</bold>-EB) state. <bold>2</bold>-EB was doped with 1 M HCl to emeraldine salt (<bold>2</bold>-ES) state. FTIR, <sup>1</sup>H and <sup>13</sup>C NMR and UV-Vis-NIR spectroscopy, and MS (ESI) was used for structural characterization. The synthesized triblock structure exhibited good electroactivity as confirmed by CV and UV-Vis-NIR spectroscopy. Self-assembling of the triblock structure in aqueous medium was assessed by DLS, TEM, and SEM. Spherical aggregates were observed with variable sizes depicting the effect of concentration and oxidation of <bold>2</bold>-LEB. Further, the aggregates showed acid/base sensitivity as evaluated by doping and dedoping of <bold>2</bold>-EB with 1 M HCl and 1 M NH<sub>4</sub>OH, respectively. Future applications in drug delivery and sensors are envisaged for such tunable self-assembled nanostructures in aqueous media.</p>