Growth Mechanism of Strain-Dependent Morphological Change in PEDOT:PSS Films

Abstract

Understanding the mechanism of the strain-dependent conductivity change in polymers in stretched conditions is important. We observed a strain-induced growth of the conductive regions of PEDOT:PSS films, induced by a coalescence of conductive PEDOT-rich cores. This growth due to coalescence leads to a gradual decrease in the electrical resistivity up to 95%, independent of the thickness of the PEDOT:PSS films. The primary mechanism for the evolution of the PEDOT-rich cores proceeds by the cores growing larger as they consuming relatively smaller cores. This process is caused by a strain-induced local rearrangement of PEDOT segments in the vicinity of PSS shells around the cores and also changes the chemical environment in PEDOT, induced by the electron-withdrawing effects around the PEDOT chains. The strain-induced growth mechanism is beneficial to understanding the phenomenon of polymeric chain rearrangement in mechanical deformation and to modulating the electrical conductivity for practical applications.

Potential Applications of Conducting Polymers to Reduce Secondary Bacterial Infections among COVID-19 Patients: a Review

“…Lee et al [ 51 ] discovered that the doping of PEDOT: PSS with DMSO induced morphological changes. The observed changes were an increase in PEDOT grain size and improved connectivity between PEDOT chains.…”

Regulating the Surface Passivation and Residual Strain in Pure Tin Perovskite Films

“…As shown in Figure 4b, the target had a reduced microstrain compared to that of the control, which indicates that post-treatment of the Cs 0.1 FA 0.9 SnI 3 perovskite layer by ThMAI also contributes to strain relaxation consistent with the changes of their morphologies (Figure 4c,d). 25 Releasing strain has been reported as an effective way to reduce defects and facilitate the lattice ordering of perovskite films, thereby ultimately improving the device stability. 26−28 This suggests that the introduction of ThMAI in the Cs 0.1 FA 0.9 SnI 3 perovskite layer will be beneficial for restraining the crystal defects and enhancing the intrinsic stability.…”

Electrical Characterization of Thin PEDOT:PSS Films on Alumina and Thiol–Ene Substrates

“…On the other hand, when the rapid change in resistance process was already over, i.e., during the 3-10 cycles, the average GF for the PEDOT:PSS films became negative and was equal to −0.19, regardless of the substrate used. This result is the superposition of geometrical and piezoresistive effects partially cancelling each other [31]. The geometric component of GF is predetermined by the Poisson's ratio ν and can be expressed as 1 + 2ν.…”

“…However, the electrical properties of PEDOT:PSS thin films are highly dependent on the processing methods, environmental factors, such as temperature and humidity, applied stresses, and peculiarities of the substrate [29][30][31]. It has been proposed to use dimethyl sulfoxide (DMSO) additives, ethylene glycol (EG), or strong acid treatment in order to increase the stability of the films [32][33][34].…”