• 文献标题:   Adsorption and removal of graphene dispersants
  • 文献类型:   Article
  • 作  者:   IRIN F, HANSEN MJ, BARI R, PARVIZ D, METZLER SD, BHATTACHARIA SK, GREEN MJ
  • 作者关键词:   pristine graphene, dispersant, dialysi, vacuum filtration, spray drying
  • 出版物名称:   JOURNAL OF COLLOID INTERFACE SCIENCE
  • ISSN:   0021-9797 EI 1095-7103
  • 通讯作者地址:   Texas A M Univ
  • 被引频次:   17
  • DOI:   10.1016/j.jcis.2015.01.058
  • 出版年:   2015

▎ 摘  要

We demonstrate three different techniques (dialysis, vacuum filtration, and spray drying) for removal of dispersants from liquid-exfoliated graphene. We evaluate these techniques for elimination of dispersants from both the bulk liquid phase and from the graphene surface. Thermogravimetric analysis (TGA) confirms dispersant removal by these treatments. Vacuum filtration (driving by convective mass transfer) is the most effective method of dispersant removal, regardless of the type of dispersant, removing up to similar to 95 wt.% of the polymeric dispersant with only similar to 7.4 wt.% decrease in graphene content. Dialysis also removes a significant fraction (similar to 70 wt.% for polymeric dispersants) of un-adsorbed dispersants without disturbing the dispersion quality. Spray drying produces re-dispersible, crumpled powder samples and eliminates much of the unabsorbed dispersants. We also show that there is no rapid desorption of dispersants from the graphene surface. In addition, electrical conductivity measurements demonstrate conductivities one order of magnitude lower for graphene drop-cast films (where excess dispersants are present) than for vacuum filtered films, confirming poor inter-sheet connectivity when excess dispersants are present. (C) 2015 Elsevier Inc. All rights reserved.