SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2021, Vol. 32 ›› Issue (4): 485-492.DOI: 10.1016/j.cjche.2020.08.023

• Materials and Product Engineering • 上一篇    

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

Yexun Shi, Chang Li, Liming Shen, Ningzhong Bao   

  1. College of Chemical Engineering, State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009, China
  • 收稿日期:2020-07-01 修回日期:2020-07-21 出版日期:2021-04-28 发布日期:2021-06-19
  • 通讯作者: Liming Shen, Ningzhong Bao
  • 基金资助:
    This research was supported by the National Key R&D Program of China (2019YFD1101200, 2019YFD1101204), Natural Science Foundation of China (51772150), and the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) Jiangsu Provincial Key Research and Development Program (BE2018008-1).

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

Yexun Shi, Chang Li, Liming Shen, Ningzhong Bao   

  1. College of Chemical Engineering, State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009, China
  • Received:2020-07-01 Revised:2020-07-21 Online:2021-04-28 Published:2021-06-19
  • Contact: Liming Shen, Ningzhong Bao
  • Supported by:
    This research was supported by the National Key R&D Program of China (2019YFD1101200, 2019YFD1101204), Natural Science Foundation of China (51772150), and the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) Jiangsu Provincial Key Research and Development Program (BE2018008-1).

摘要: The graphene oxide powder (GOP) obtained from the spray drying process often exhibits poor redispersibility which is considered due to the partial reduction of GO sheets. The reduction of drying temperature 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 assembly 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 provides useful information for understanding the relationships between the morphology, microstructure, and final re-dispersibility of GOPs.

关键词: Graphene oxide powder, Spray drying, Re-dispersibility, Oriented assembly, Layered structure

Abstract: The graphene oxide powder (GOP) obtained from the spray drying process often exhibits poor redispersibility which is considered due to the partial reduction of GO sheets. The reduction of drying temperature 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 assembly 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 provides useful information for understanding the relationships between the morphology, microstructure, and final re-dispersibility of GOPs.

Key words: Graphene oxide powder, Spray drying, Re-dispersibility, Oriented assembly, Layered structure