Quantifying the Stability–defect–layer Trade-off in Surfactant-assisted Fluid-dynamic Exfoliation of Few-layer Graphene

Abstract

In this paper we report an all-aqueous fluid-dynamic exfoliation route to low-defect few-layer graphene (FLG) using the non-ionic surfactant Triton X-100. Systematic variation of surfactant concentration (1–5 wt%) and processing time (0.5–1.5 h) revealed a quantitative interplay among stability, defect, and layer. Raman spectroscopy and 2D band Lorentzian modeling revealed that the few-layer graphene (FLG) predominantly consists of four layers, with very low defect ratios (I_D/I_G = 0.02–0.11; I_2D/I_G = 0.18–0.30). Raman imaging confirmed spatially uniform G band intensity, while the edge-activated D band signals indicated residual edge defects characteristic of shear-cleaved flakes. Transmission electron microscopy and particle size analysis yielded lateral sizes of ~1.29–1.43 µm with a narrow distribution. Fourier transform infrared spectroscopy verified that the defects were not oxidation-derived, while UV–Vis showed graphene π–π absorption at 270–276 nm. This work establishes a short-duration, low-cost, and solvent-free approach for producing stable FLG suitable for liquid-phase applications and provides process–structure metrics for benchmarking across exfoliation studies.