Enhanced thermal conductivity of cellulose nanofibril/aluminum nitride hybrid films by surface modification of aluminum nitride

In this work, gamma-aminopropyltriethoxysilane treated aluminum nitride nanosheets (TAlN) were blended with cellulose nanofibrils (CNFs), and a novel nano-flexible composite film was prepared by vacuum filtration. The interactions between the CNFs and TAlN were studied, and the effect of the amount of the added TAlN on the properties of the composites was discussed. Due to the function of silane, the dispersibility of the AlN nanosheets in the CNF substrate is improved and resulting in the formation of covalent bonds between them. The silane treatment reduces the phonon scattering between the AlN and CNF substrate interfaces; thus, the composite film exhibits excellent thermal conductivity. The in-plane thermal conductivity of the composite film reaches 5.11 W/mK when the amount of TAlN added is 25 wt%. The high thermal conductivity composite film material can realize thermal management for flexible energy storage electronic products; thus, effectively promoting the development of green flexible electronic devices. Graphic abstract