Technical Note: Core–Edge Domain Contrast Control for Ultra-High-Strength Carbon

This technical note proposes a practical, testable lever for improving ultra-high-strength carbon fiber and its translation into composite performance: controlling and measuring core–edge domain contrast. The core idea is that elite fiber performance is often limited by edge-domain behavior (surface chemistry, sizing distribution, defect-driven crack initiation, and interfacial load transfer), even when bulk corridor alignment and tensile strength are high. The note defines a compact “Core–Edge Domain Contrast” (CEDC) signature built from three categories: (1) core corridor quality (alignment and variability), (2) edge-domain chemistry and interface readiness (surface functional groups, sizing level/uniformity), and (3) failure initiation indicators (variability statistics and simple interface tests). A minimal, low-burden test matrix is included to evaluate whether CEDC predicts composite interfacial performance and reliability more effectively than tensile strength alone. This is a non-proprietary research contribution intended to be easy to reproduce and extend. It does not disclose enabling manufacturing recipes. If useful, citation is appreciated.