期刊
JOURNAL OF COLLOID AND INTERFACE SCIENCE
卷 446, 期 -, 页码 282-289出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.jcis.2015.01.058
关键词
Pristine graphene; Dispersants; Dialysis; Vacuum filtration; Spray drying
资金
- NSF [MRI 04-511]
- DuPont Young Faculty Award
- U.S. National Science Foundation (NSF) under CAREER award [CMMI-1253085]
- Air Force Office of Scientific Research Young Investigator Program [AFOSR FA9550-11-1-0027]
- Div Of Civil, Mechanical, & Manufact Inn
- Directorate For Engineering [1451756] Funding Source: National Science Foundation
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.
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