Nanospherical Aggregation of Isothiouronium-Terminated Amphiphilic Polythiophene: Preparation and Vapor-Phase Detection of Volatile Organic Compounds

Abstract

Cationic isothiouronium-terminated amphiphilic poly(3-octylthiophene) IPOT has been synthesized by the reaction of bromoethylene-terminated poly(3-octylthiophene) with 1-(2-(2-methoxyethoxy)ethyl)-3-methylthiourea. By performing gel-permeation chromatography analysis, we estimated the number-average molecular weight (M(n)) and the polydispersity index (PDI) to be 1.07 x 10(4) and 1.48, respectively. The incorporation of an isothiouronium unit at the terminal position renders the polymer amphiphilic. Well-dispersed spherical aggregates were formed with increasing H2O content in the THF solution and were characterized by FE-SEM and powder XRD measurements. We thus proposed a core/shell-type micelle with a poly(3-octylthiophene) segment as the core and an isothiouronium segment as the shell, exposing the hydrophilic methoxyethoxy pendant. The change in morphology to a spherical shape led to a bathochromic shift of the absorption band with decreasing fluorescence intensity, enabling us to use it as a fluorimetric "off-on" sensor for volatile organic compounds (VOCs) where a quick response to THF was observed on the IPOT aggregate-coated TLC plate.

Regioregularity and deposition effect on the physical/chemical properties of polythiophene derivatives films

“…Both regiorandom P3BT and P3OT LB films showed a broad band centered at higher wavelengths (452 and 444, respectively) when compared to the respective LS films (439 and 436, respectively) (table 2). This result indicates a higher conjugation length [30,31] for the LB films of regiorandom P3AT, and therefore a more ordered structure provided by the LB deposition technique in this case. The absence of the vibronic structure in any of the regiorandom P3ATs films spectra can be assigned to an inhomogeneous broadening of the electronic π-π * transition produced by a relatively wider distribution of conjugation lengths at a lower mean length [32].…”

An Electrochemical Approach to Quantification of Volatile Organic Solvents Dispersed in Solution – Towards Bipolar Electrode Sensors

“…As model analyte, styrene was used. PVDF hydrophobic membranes were modified with polyoctylthiophene (POT) acknowledging its applicability of VOCs sensing using different techniques [16,21,22].…”