Interfacial Synthesis and Widely Controllable Conductivity of Polythiophene Microparticles

Abstract

Fine polythiophene (PTh) microparticles were successfully synthesized by a novel interfacial polymerization at a dynamic interface between two immiscible solvents, i.e., n-hexane and acetonitrile or nitromethane containing thiophene and oxidant, respectively. The polymerization yield, size, and electrical conductivity of the microparticles are optimized by facilely regulating the medium species, oxidant species, oxidant/monomer ratio, monomer concentration, and polymerization temperature. The microparticles were thoroughly characterized by IR, UV-vis spectroscopy, wide-angle X-ray diffractometry, laser particle-size analyzer, and simultaneous TG-DSC technique. The yield rises with increasing oxidant/monomer ratio, monomer concentration, and polymerization temperature. However, low monomer concentration, low polymerization temperature, and modest oxidant/monomer ratio are all favorable for the formation of the PTh with good, large pi-conjugation and high conductivity. With decreasing the thiophene concentration from 200 to 50 mM at a fixed FeCl3/thiophene molar ratio of 3 at 0 degrees C in hexane/nitromethane biphase system, the PTh obtained exhibits a steadily enhanced conductivity from 10(-12) to 0.01 S cm(-1) and gradually darkening color from crimson to black. Under the same conditions, the PTh obtained in hexane/acetonitrile usually possesses lower yield but higher conductivity than that in hexane/nitromethane. The conductivity will be further enhanced to 1.1 and 4.4 S cm(-1) if the PTh powders are doped in iodine vapor and simply carbonized at 25 through 999 degrees C in nitrogen, respectively. The PTh is fine particles with the number-average diameter of 2.67-3.95 microm and low size polydispersity index between 1.12 and 1.23. The black particles carbonized at 25 to 999 degrees C are much smaller than original PTh particles, with the number-average diameter of 279 nm and size polydispersity index of 1.09. This interfacial approach provides an optimal synthesis of unique PTh microparticles with large pi-conjugation, high conductivity, black color, uniform size, good insolubility, excellent infusibility, high thermostability, and high yield of electrically conducting char at 999 degrees C.

Cu content dependence of morphological, structural and optical properties for Cu2ZnGeS4 thin films synthesized by sulfurization of sputtered precursors

“…), which can be potentially applicable for manufacturing solar cells, have drawn considerable interest [1][2][3][4][5]. Among them, CIGS thin film solar cells have been successfully developed and are being commercialized, which exhibits a record efficiency of 20.8% at the laboratory level [1].…”

A high-performance supercapacitor based on a polythiophene/multiwalled carbon nanotube composite by electropolymerization in an ionic liquid microemulsion

“…The band at 1635, 1247, 1103 and 615 cm À1 is assigned to C]C asymmetric stretching vibration modes of the thiophene ring, C-H bending, C-H in-plane deformation and C-S-C ring deformation, respectively. 48,49 The above results demonstrated that the PTh/ MWCNT composite has been successfully synthesized in the O/ IL microemulsion.…”

Electroactive and bioactive films of random copolymers containing terthiophene, carboxyl and Schiff base functionalities in the main chain

“…The most evident peaks in this range appeared as follows: the peak at around 568 cm -1 attributable to  thiophene ring vibration 60 ; that at 695 cm -1  4 cm -1 due to C-S-C ring deformation; and the peak at 793 cm -1 due to CH out-of-plane bending vibration ( C-H) of 2,5-substituted thiophene rings. 81,82 A strong doublet-like band centered at 1260 cm -1 and at 1050  10 cm -1 is also present in this range which could be due to the  C-H bending in doped PTh chains 81 . An absorption band centered at 1660 cm -1  20 cm -1 can be seen in the spectra of all the investigated materials due to the conjugation between the thiophene rings along the polymer chains.…”