Flexible Conductive Substrate Incorporating a Submicrometer Co-continuous Polyaniline Phase within Polyethylene by Controlled Crazing

Abstract

A polyethylene film with an incorporated nanodispersed polyaniline conductive network was developed by controlled crazing in a high-pressure reactor while immersed in an emulsified medium of aniline in chloroform. The resulting conductive material exhibited an average through-plane electron conductivity of 2 × 10–2 S·cm–1, within an order of magnitude of brittle doped polyaniline (1.2 × 10–1 S·cm–1), yet retained the ductility of the polyethylene matrix. It was also shown that 90% of the original conductivity was retained after 1% elongation. Embedded polyaniline fibers acted both as a nucleating agent to reduce the size of crystallites for controlled crazing and as submicrometer conductive nodes, connecting neighboring conductive conduits formed inside the crazing voids, with both effects contributing to the increasing electrical permeability of the secondary phase. For comparison, montmorillonite and TiO2 particles were tested as alternative nucleating agents to verify the effect of the preliminary embedded polyaniline fibers on the matrix morphology and, consequently, the conductivity acquired.

Flexible nanoscale co‐continuous structures prepared by controlled crazing of ethylene‐octene elastomers and in‐situ polymerization of conductive networks

“…In our previous research, in situ emulsion polymerization of aniline in the polyethylene matrix yielded a highly conductive secondary phase of PANI‐DBSA. [ 3 ] This resembles the approach of stretching the samples in the acrylic monomer, only replacing the hydrogel secondary phase with polyaniline to achieve electron conductivity. However, an attempt to follow this approach with pure Engage 8003 failed since the partial elastic recovery of the matrix displaced the incorporated polyaniline conductive phase when the deformed samples were taken out of the rig, causing the conductivity to drop to an undetectable level.…”

“…Electron conductivity of the POE‐PCL‐PANI samples was also measured in response to multiple stress‐relaxation cycles by the procedure developed for our previous research. [ 3 ] The test specimens were prepared as described in the previous section. They were elongated within the so‐called survival range determined from the previous test.…”

“…The general deformation procedure was basically adopted from the two previous studies. [3,4] The custom tensile rig was contained inside a high-pressure reactor, which was frequently depressurized to carry out a step-wise deformation of the sample, followed by purging and subsequent re-pressurizing to 2.76 MPa (400 psi) with dry nitrogen.…”

“…The voids originate from crystallization when chains are consumed from the amorphous phase in the formation of crystals, resulting in depleted areas at the interface. [3,4] The crystalline and amorphous fractions in POEs, in contrast, are formed from the different chain segments (ethylene and octene, respectively) without causing chain depletion at the interface and, therefore, resulting in a void-free initial material morphology. However, while a POE is stretched, the hard domains act as stress concentrators on which the primary voids to initiate crazing are formed.…”

Evolution of the Surface Structure and Functional Properties of the Electroconducting Polymer Coatings onto Porous Films

“…The electrical conductivity of the composites is comparable (or higher) with known values for conducting polymer-based hybrid systems. For instance, the composites with PANI layers have conductivities 2 × 10 −2 and 0.5-5.8 S/cm for (PE support)/PANI and (PP support)/PANI, respectively [44,45]; the composites with PPy layers on PE and PP supports in [47][48][49] show conductivity 3.25-4.46 S/cm; (PVDF support)/PANI composites were reported to have conductivity 10 −1 -10 −4 S/cm [46,50].…”