Constructing a Layer-by-Layer Architecture to Prepare a Transparent, Strong, and Thermally Conductive Boron Nitride Nanosheet/Cellulose Nanofiber Multilayer Film

Abstract

Constructing a layer-by-layer framework is a highly efficient strategy for preparing thermal management materials with excellent performance. In this report, thermal oxidation and ultrasonic exfoliation of hexagonal boron nitride can prepare hydroxylated boron nitride nanosheet (BNNS-OH). BNNS-OH layer and cellulose nanofiber (CNF) layer are assembled, respectively, on the CNF surface to form a homogeneous film by vacuum-assisted self-assembly and hydrogen bond interaction. With the increase in the number of BNNS-OH layers and CNF layers, the in-plane thermal conductivity of the multilayer film increases dramatically, which is up to 1.47 W•m −1 •K −1 for 0.16 wt % BNNS-OH, and the thermal conductivity efficiency of the unit weight filler is up to 1142%. The multilayer films maintain optical transparency and mechanical property owing to the hierarchical structure and ultralow filler content. This work provides a new method to prepare a good transparent, mechanically and thermally conductive cellulose nanofiber/boron nitride nanosheet multilayer film, which is promising for thermal dissipation in a series of modern devices.

Ultra-Robust Thermoconductive Films Made from Aramid Nanofiber and Boron Nitride Nanosheet for Thermal Management Application

“…As shown in Figure S6a ( Supplementary Materials ), the FT-IR spectra of BNNS@Ag were very similar to that of BNNS. The former presented characteristic peaks at 1348 cm −1 and 788 cm −1 , while the latter presented characteristic peaks at 1342 cm −1 and 772 cm −1 , which also accorded with other reports [ 36 , 55 , 56 ]. The two peaks contained the vibrations of B−N stretching and B−N bending, respectively, while the slight blue shift of BNNS@Ag relative to BNNS could be attributed to the slight change in lattice vibration caused by the successful adsorption of AgNP on the surface of BNNS.…”

“…Thermogravimetric analysis (TGA) of the BNNS, the BNNS@Ag, and composite films was conducted using a Mettler Toledo thermogravimetric analyzer (Barcelona, Spain) from 30 °C to 800 °C at a heating rate of 10 °C/min under a N 2 flow (20 mL/min). The in-plane thermal conductivity (λ) was calculated via Equation (2) [ 36 , 37 ] as follows: where ρ is the density of composite film, Cp is the specific heat capacity of composite films, and α is the thermal diffusivity of the composite films. The Cp values of composite films were measured using differential scanning calorimetry (DSC, TA 2100, PerkinElmer, Waltham, MA, USA) with the Sapphire method.…”

An overview of boron nitride based polymer nanocomposites

“…Here, the in‐plane thermal conductivity of the multilayer film is found to be increased dramatically and the thermal conductivity efficiency of the unit weight filler is raised up to 1,142%. [ 154 ] CNF/BNNS aerogel exhibited better thermal conductivity compared to CNF aerogel. [ 155 ] Low‐cost and environment friendly method was developed by Xie et al for the fabrication of biodegradable, hydrophilic, and thermally conductive RCF textile containing 60 wt% BNNS.…”

Ultra‐Flexible, Dielectric, and Thermostable Boron Nitride‐Graphene Fluoride Hybrid Films for Efficient Thermal Management

“…The high dispersion is attributed to the modification of the BN lattice by the introduction of hydrophilic OH functional groups. [ 37 ] The FTIR spectrum of pristine BN only reveals the typical in‐plane BN stretching vibration at 1385 cm −1 and out‐of‐plane B‐N bending vibration at 808 cm −1 , while the exfoliated BNNS‐OH exhibits an additional OH stretching vibration at 3410 cm −1 (Figure S1, Supporting Information), giving a strong proof for the hydroxylation of BNNS. Figure 2b shows that most BNNS have lateral dimensions in the range of 100–900 nm.…”