Observable Temperature-Dependent Compaction−Decompaction of Cationic Polythiophene in the Presence of Iodide

Abstract

Investigation on compaction and decompaction of polymers is very important since it is a fundamental problem in polymer physics. With the aids of atomic force microscope (AFM) and dynamic light scattering (DLS) measurements in this contribution, the temperature-dependent compaction/decompaction transition process of water-soluble cationic polythiophene (PT) was investigated in the presence of KI. The above process is characterized by the red-to-yellow color change and fluorescence recovery and is reversible during the heating-cooling cycles in the range from 25 to 55 °C, indicating that the compaction and decompaction of polymer can be employed as a temperature indicator.

Water-soluble ionic polythiophenes for biological and analytical applications

“…The AFM study indicated that the thickness of free polymer is ca 120 nm at both 25 and 55 °C, but the thickness decreases to ca 60 nm in the presence of KI at 25 °C. From these data it was claimed that at 25 °C in the presence of KI the polymer adopts a less conjugated, nonplanar conformation …”

“…(A) Schematic of polythiophene conformational change when exposed to ligands or varying surroundings and (B) the observable temperature‐dependent compaction/de‐compaction of polythiophene in the presence of KI. (Reproduced from Wang et al )…”

Nuclear fast red‐based colorimetric sensors for sensitive and selective detection of Ag ions

“…In recent years, colorimetric sensing has drawn increasing attention to decrease experimental cost, simplify the sensing process and determine the target concentration visually. This method has been used for many kinds of target detection with satisfactory results . Significant advances have been made in the development of colorimetric sensors for Ag + detection, however, there is still a need to set up a convenient colorimetric method for Ag + that has a wide detection range, low determination limit, as well as high selectivity.…”

Interactions of a zwitterionic thiophene-based conjugated polymer with surfactants

“…Conformational changes can be promoted by changing temperature, pH, ionic strength, cations, anions, surfactants, nucleic acids, proteins, etc. [2][3][4][5][6][7][8][9][10] A detailed study of the optical transitions of a water-soluble PT induced by surfactant addition was performed by Knaapila and coworkers. 8,9 The optical transitions are correlated with the changes in the type of CPE-surfactant aggregate formed in solution.…”