Scalable, Robust, Low‐Cost, and Highly Thermally Conductive Anisotropic Nanocomposite Films for Safe and Efficient Thermal Management

Recently, soaring developments in microelectronics raise an urgent demand for thermal management materials to tackle their “overheating” concerns. Polymer nanocomposites are promising candidates but often suffer from their inability of mass production, high‐cost, poor mechanical robustness, and even flammability. Hence, it is desirable to scalably fabricate low‐cost, robust polymeric nanocomposites that are highly thermally conductive and fire‐retardant to ensure safe and efficient thermal management. Herein, the scalable production of nacre‐like anisotropic nanocomposite films using the layer‐by‐layer assembly of phenylphosphonic acid@graphene nanoplatelets (PPA@GNPs)‐poly(vinyl alcohol) (PVA) layer and GNPs layers, is demonstrated. The PPA serves as interfacial modifiers and fire retardants for flammable PVA (film‐forming agent) and GNPs (inexpensive conductive nanofillers) via hydrogen‐bonding and π–π stacking. The resultant nanocomposite exhibits a high flexibility, high tensile strength of 259 MPa, and an ultrahigh in‐plane thermal conductivity of 82.4 W m‐1 K‐1, making it effectively cool smartphone and high‐power light emitting diode modules, outperforming commercial tinfoil counterparts. Moreover, the as‐designed nanocomposites are intrinsically fire‐retardant and can shield electromagnetic interference. This work offers a general strategy for mass production of thermally conductive nanocomposites holding great promise as thermal management materials in electronic, military, and aerospace fields. The scalable production of nacre‐like PVA multifunctional nanocomposite films is presented by using the LBL assembly. The resultant low‐cost nanocomposite achieves desirable flexibility, high tensile strength of 259 MPa, and an ultrahigh in‐plane thermal conductivity of 82.4 W m–1 K–1, making it effectively cool for both smartphone and high‐power LED modules. Moreover, as‐designed nanocomposites are intrinsically fire retardant.