Abstract
It is shown that magnetite nanoparticles (MagNPs) grafted with polyethylene glycol (PEG) self-assemble and short-range-order as 2D films at surfaces of aqueous suspensions by manipulating salt concentrations. Synchrotron X-ray reflectivity and grazing-incidence small angle X-ray scattering studies reveal that K2CO3 induces the migration of the PEG-MagNPs to the liquid/vapor interface to form a Gibbs layer of monoparticle in thickness. As the salt concentration and/or nanoparticle concentration increase, the surface-adsorbed nanoparticles become more organized. And further increase in salt concentration leads to the growth of an additional incomplete nanoparticle layer contiguous to the first one at the vapor/liquid interface that remains intact.
| Original language | English |
|---|---|
| Article number | 1701149 |
| Journal | Advanced Materials Interfaces |
| Volume | 5 |
| Issue number | 6 |
| DOIs | |
| State | Published - Mar 23 2018 |
| Externally published | Yes |
Funding
The authors thank Ivan Kuzmenko at beamline 9ID-B, and Xiaobing Zuo, at beamline 12ID-B, APS, Argonne National Laboratory for technical support in liquid surface scattering measurements and solution small angle X-ray scattering measurements, respectively. This research was supported by the U.S. Department of Energy (U.S. DOE), Office of Basic Energy Sciences, Division of Materials Sciences and Engineering. Ames Laboratory is operated for the U.S. DOE by Iowa State University under Contract No. DE-AC02-07CH11358. Use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. DOE Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357.
Keywords
- grazing-incidence X-ray diffraction at small angles (GISAXS)
- magnetitite nanoparticles
- nanoparticle self-assembly
- PEG-functionalized nanoparticles
- X-ray reflectivity