Construction and Mechanism Analysis of a Self-Assembled Conductive Network in DGEBA/PEI/HRGO Nanocomposites by Controlling Filler Selective Localization

Efficiently tuning the electrical performance of PBTTT-C14 thin film viainsitucontrollable multiple precursors (Al2O3:ZnO) vapor phase infiltration

Conjugated polymer-based organic/inorganic hybrid materials become the current research frontier and show great potential to integrate flexible polymers and rigid solid materials, which have been widely used in the field of various flexible electronics and optical devices. In this study, based on the multiple vapor phase infiltration (VPI) process, various precursor molecules (diethylzinc DEZ, trimethylaluminum TMA, H2O) are applied for thein situmodification of PBTTT-C14 films. The conductivity of the PBTTT-C14/Al2O3:ZnO (AZO) film is significantly enhanced, and the maximum value of conductivity is 1.16 S cm-1, which is eight orders of magnitude higher than the undoped PBTTT-C14 thin film. Here, the change of morphologies and crystalline states are analyzed via SEM, AFM, and XRD. And the chemical changes during the VPI process of PBTTT-C14 are characterized through Raman, XPS, and UV-vis. During the AZO VPI process, the formation of new ZnS matrix in the polymer subsurface can generate new additional electron conduction pathways through the crosslinking of polymer chains with inorganic materials, and the addition of Al2O3can bring about the increase of average grain size of ZnO crystals, which is also benefit to the conductivity increase of PBTTT-C14 thin film. Generally, the synergistic effect between the inorganic and polymer constituents results in the significantly enhancement of the conductivity of PBTTT-C14/AZO thin films.

Enhanced Electromagnetic Interference Shielding Properties of Immiscible Polyblends with Selective Localization of Reduced Graphene Oxide Networks

Herein, an effective technique of curing reaction-induced phase separation (CRIPS) was used to construct a reduced graphene oxide (RGO) network in the immiscible diglycidyl ether of the bisphenol A/polyetherimide (DGEBA/PEI) polyblend system. The unique chemical reduction of RGO facilitated the reduction of oxygenated groups and simultaneously appended amino groups that stimulate the curing process. The selective interfacial localization of RGO was predicted numerically by the harmonic and geometric mean technique and further confirmed by field emission transmission electron microscopy (FETEM) analysis. Due to interfacial localization, the electrical conductivity was increased to 366 S/m with 3 wt.% RGO reinforcement. The thermomechanical properties of nanocomposites were determined by dynamic mechanical analysis (DMA). The storage modulus of 3 wt.% RGO-reinforced polyblend exhibited an improvement of ~15%, and glass transition temperature (T_g) was 10.1 °C higher over neat DGEBA. Furthermore, the total shielding effectiveness (SE_T) was increased to 25.8 dB in the X-band region, with only 3 wt.% RGO, which represents ~99.9% shielding efficiency. These phase separation-controlled nanocomposites with selective localization of electrically conductive nanofiller at a low concentration will extend the applicability of polyblends to multifunctional structural nanocomposite applications.