An approach is described for the synthesis of controlled submicron interpenetrating networks with distinct functional features in commodity polymers, based on a mechanism of crazing and polymerization. In this work, ion conductivity was introduced into polyethylene with only minor losses in its mechanical properties, using a highly branched acrylic hydrogel. Control over the porous network developed in the matrix was gained by the addition of a crystallizing nucleating agent, which was used to increase the number and reduce the size of crystallites. Variation of experimental conditions, such as the degree of elongation and applied reaction pressure, produced different morphologies and conductivities for the co-continuous alloy. The samples were deformed in a liquid medium that possessed an affinity for the matrix material and acted both as a surface-active agent for the crazing and as a reactant for the conductive phase. Without pressure, deforming by 100% strain yielded a conductivity of 5.67 × 10 −7 S•cm −1 for the polymer specimen. Simultaneously increasing the system pressure while constantly straining a specimen enabled further enhancement in conductivity. As a particular example, elongation of 100% and applied pressure up to 2.76 MPa ensured conductivity nearly equal to that of the pure hydrogel at 4.43 × 10 −4 S•cm −1 .

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.

An approach based on controlled crazing and post‐polymerization was used to incorporate a nanoscaled conductive co‐continuous network into commercial ENGAGE™ Polyolefin Elastomers (POEs). Three POE films of differing crystallinity and phase morphology were stretched in a reactive mixture of acrylic polymerization precursors that possessed an affinity for the olefinic materials and acted as a surface‐active agent for craze promotion. As a result, a rigid acrylic hydrogel phase was grown in the void space associated with crazing, which prevented the formed channels from collapsing after mechanical stresses were removed. The hydrogel phase offered ion conductivity properties to the POE. Simply replacing the acrylic monomer with an aniline emulsion for polymerization did not lead to the same outcome in terms of a continuous network; the materials became insulative after the removal of mechanical stresses due to fragmentation of the polyaniline channels from the unrestrained elastic relaxation of the POE. This problem was overcome by solution‐casting POE with polycaprolactone (PCL) into films and, subsequently, partially dissolving and leaching PCL from the blend while a sample was stretched in an aniline emulsion medium containing formic acid. The residual PCL left in the crazes reinforced the polyaniline to prevent fragmentation, allowing the formation of a highly electron‐conductive secondary phase.