Tian Xiaojuan, Li Yun, Chen Zhuo, Li Qi, Hou Liqiang, Wu Jiaye, Tang Yushu, Li Yongfeng
State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing, Changping, 102249, P. R. China.
Sci Rep. 2017 Dec 19;7(1):17794. doi: 10.1038/s41598-017-18149-5.
Boron nitride nanosheets (BNNS) hold the similar two-dimensional structure as graphene and unique properties complementary to graphene, which makes it attractive in application ranging from electronics to energy storage. The exfoliation of boron nitride (BN) still remains challenge and hinders the applications of BNNS. In this work, the preparation of BNNS has been realized by a shear-assisted supercritical CO exfoliation process, during which supercritical CO intercalates and diffuses between boron nitride layers, and then the exfoliation of BN layers is obtained in the rapid depressurization process by overcoming the van der Waals forces. Our results indicate that the bulk boron nitride has been successfully exfoliated into thin nanosheets with an average 6 layers. It is found that the produced BNNS is well-dispersed in isopropyl alcohol (IPA) with a higher extinction coefficient compared with the bulk BN. Moreover, the BNNS/epoxy composite used as thermal interface materials has been prepared. The introduction of BNNS results in a 313% enhancement in thermal conductivity. Our results demonstrate that BNNS produced by supercritical CO exfoliation show great potential applications for heat dissipation of high efficiency electronics.
氮化硼纳米片（BNNS）具有与石墨烯相似的二维结构以及与石墨烯互补的独特性能，这使其在从电子到储能等广泛应用领域具有吸引力。氮化硼（BN）的剥离仍然是一个挑战，阻碍了BNNS的应用。在这项工作中，通过剪切辅助超临界CO₂剥离工艺实现了BNNS的制备，在此过程中，超临界CO₂插入并在氮化硼层之间扩散，然后在快速降压过程中通过克服范德华力实现BN层的剥离。我们的结果表明，块状氮化硼已成功剥离成平均6层的薄纳米片。研究发现，所制备的BNNS在异丙醇（IPA）中分散良好，与块状BN相比具有更高的消光系数。此外，还制备了用作热界面材料的BNNS/环氧树脂复合材料。BNNS的引入使热导率提高了313%。我们的结果表明，通过超临界CO₂剥离制备的BNNS在高效电子产品散热方面具有巨大的潜在应用价值。
