Delamination of Vermiculite into Ultrahigh‐Aspect‐Ratio Nanosheets

The applicability of sustainable materials in the packaging industry is currently limited by the poor gas barrier performance of most biodegradable polymers. Incorporation of high–aspect‐ratio nanosheet fillers can significantly enhance barrier properties, yet large‐scale production of such fillers remains challenging. Here, we report a gentle route to produce vermiculite (VMT) nanosheets with unprecedented aspect ratios exceeding 10,000 via one‐dimensional (1D) dissolution. Complete ion exchange was achieved using citrate as complexing agent, which efficiently removed the pristine interlayer Mg 2+ and enabled quantitative exchange with monovalent cations. Intercalation with bulky organocations resulted in spontaneous 1D dissolution of VMT in water, yielding translucent, birefringent gels of delaminated nanosheets in up to 71% yield. Structural and morphological analysis by X‐ray diffraction (XRD), small‐angle X‐ray scattering (SAXS), and atomic force microscopy (AFM) confirmed the formation of monolayer nanosheets with lateral sizes exceeding 10 µm. The combination of citrate‐assisted exchange and mild spontaneous delamination preserves the intrinsic crystal diameter, enabling aspect ratios that surpass previously reported benchmarks for natural clays. The performance of these nanosheets as barrier pigments showed a remarkable potential for future applications in environmentally friendly packaging.