Structure-dependent re-dispersibility of graphene oxide powders prepared by fast spray drying

• 作者: Yexun Shi Chang Li Liming Shen Ningzhong Bao
• 来源期刊: 中国化学工程学报（英文版）
• 年，卷（期）: 2021,（4）
• 所属期刊栏目: Materials and Product Engineering
• 页码范围: 485-492
• 页数: 8页
• 语种: 英文

摘要

The graphene oxide powder (GOP) obtained from the spray drying process often exhibits poor re-dispersibility which is considered due to the partial reduction of GO sheets. The reduction of drying tem-perature can effectively increase the re-dispersibility of GOP, but result in a decreased drying efficiency. Herein, we found that the re-dispersibility of GOP is strongly affected by its microstructure, which is determined by the feed concentration. With the increase of feed concentration, the GO nanosheet assem-bly varies from the disordered stacking to relatively oriented assembly, making the morphology of the GOP transform from ball-like (the most crumpled one) to flake-like (the least crumpled one), and the 0.8 mg·ml-1 is the threshold concentration for the morphology, structure, and re-dispersibility change. Once the feed concentration reaches 0.8 mg·ml-1, the appearance of the nematic phase in droplet ensures the relatively oriented assembly of GO sheets to form the layered structure with a low crumpling degree, which greatly improves the polar parts surface tension of the solid GOP, making the GOP easier to form hydrogen bonding with water during the redispersion process, thus stabilizing dispersion. This work pro-vides useful information for understanding the relationships between the morphology, microstructure, and final re-dispersibility of GOPs.