Hybrid CNT–Polymer Nanocomposites Processed by Scalable Routes for Enhanced Dielectric Properties and EMI Shielding

Lightweight polymer nanocomposites are promising sustainable alternatives to metallic electromagnetic interference (EMI) shields, but nanofiller agglomeration, high dielectric loss at practical loadings, and limited GHz stability hinder deployment. Here, poly(vinylidene fluoride) (PVDF) and epoxy are reinforced with functionalized multi-walled carbon nanotubes (MWCNTs), reduced graphene oxide (rGO), and carbon black (CB) via scalable melt blending and solution casting. SEM, TEM, FTIR, and XPS confirm uniform dispersion and strong interfacial adhesion. CNT/PVDF nanocomposites exhibit a dielectric constant ε′ ≈ 180 and loss tangent tan δ < 0.05 at ≤1 wt% CNT, retained under ±50 V DC bias and thermal cycling to 150 °C. Hybrid CNT+rGO and CNT+CB systems exploit 1D/2D/0D synergy, achieving EMI shielding effectiveness >25 dB in the 2–8 GHz band while remaining electrically insulating. A Random Forest model (R2 > 0.90) predicts dielectric response from filler type, morphology, and processing, reducing experimental iterations by ∼60%. This integrated experimental–computational framework provides a practical route to GHz-stable, high-permittivity, low-loss nanocomposites for aerospace, automotive, and wearable electronics.