Abstract
In this investigation, the utility of a static light scattering (SLS) technique to characterize aggregate morphology of two-dimensional engineered nanomaterials (2D ENMs) was systematically evaluated. The aggregation of graphene oxide (GO) and lithiated-molybdenum disulfide (Li-MoS2) were measured and compared to that of a spherical reference colloid, carboxylate-modified latex (CML) nanoparticles. The critical coagulation concentration (CCC) for all dispersions was determined via analysis of aggregation kinetics using time-resolved dynamic light scattering. This technique allowed for the elucidation of the transition from the reaction-limited aggregation (RLA) regime to diffusion-limited aggregation (DLA). The findings of this study support the aggregation trends predicted by Derjaguin-Landau-Verwey-Overbeek (DLVO) theory and recent computer simulations of aggregation kinetics. For all nanomaterials, as ionic strength increased towards the respective the CCC, fractal dimension decreased; any increase in ionic strength beyond the CCC did not yield significant change in fractal dimension. Across comparable primary particle sizes and using both carbonaceous (GO) and inorganic (Li-MoS2) 2D ENMs, this study further supports the use of SLS for the measurement of fractal dimension for 2D materials. To further support this claim, the aggregate morphology of GO in both RLA and DLA regimes was measured via cryogenic transmission electron microscopy.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 849-853 |
| Number of pages | 5 |
| Journal | Journal of Colloid And Interface Science |
| Volume | 561 |
| DOIs | |
| State | Published - Mar 1 2020 |
Funding
This study has been supported by a combination of National Science Foundation (NSF) and Environmental Protection Agency (EPA). S.D. Story was supported by the NSF IGERT: Water SENSE ? Water Social, Engineering, and Natural Sciences Engagement Program (Grant # 1144635). S. Walker's participation and the work more broadly were also funded through the UC-CEIN (University of California Center for Environmental Implications of Nanotechnology), which is supported by the NSF and the EPA under Cooperative Agreement Number DBI 0830117. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF or the EPA. This work has not been subjected to EPA review and no official endorsement should be inferred. We would like to acknowledge Dr. Ian Marcus for his efforts editing the manuscript. This study has been supported by a combination of National Science Foundation (NSF) and Environmental Protection Agency (EPA). S.D. Story was supported by the NSF IGERT: Water SENSE \u2013 Water Social, Engineering, and Natural Sciences Engagement Program (Grant # 1144635 ). S. Walker's participation and the work more broadly were also funded through the UC-CEIN (University of California Center for Environmental Implications of Nanotechnology), which is supported by the NSF and the EPA under Cooperative Agreement Number DBI 0830117 . Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF or the EPA. This work has not been subjected to EPA review and no official endorsement should be inferred. We would like to acknowledge Dr. Ian Marcus for his efforts editing the manuscript.
Keywords
- Aggregate morphology
- Critical coagulation concentration
- Fractal dimension
- Static light scattering
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Biomaterials
- Surfaces, Coatings and Films
- Colloid and Surface Chemistry