Synthesis and suspension rheology of titania nanoparticles grafted with zwitterionic polymer brushes
- Title
- Synthesis and suspension rheology of titania nanoparticles grafted with zwitterionic polymer brushes
- Author
- 김진웅
- Keywords
- Colloidal gel; Colloidal suspensions; Rheology; Titania
- Issue Date
- 2012-11
- Publisher
- ACADEMIC PRESS INC ELSEVIER SCIENCE
- Citation
- Journal of Colloid And Interface Science,2012, 386(1), P.135-140
- Abstract
- Titania nanoparticles were modified by free-radical graft polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) at the particle surface, resulting in the formation of a 1-2 nm thick polymer brush. The zwitterionic nature of the polymer layer suggests that the suspension stability is a delicate function of pH, as well as volume fraction, salt concentration and the presence of charged or un-charged additives which may act as depletants or to screen charge interactions in the system. In this context, we characterized the suspension rheology as a function of volume fraction, pH, ionic strength and the concentration of surfactants in the suspension. Near-neutral pH, the brush layer is effective in stabilizing particles against aggregation with Newtonian behavior observed for volume fractions approaching 14%. Flocculation of particles and an onset of shear-thinning behavior was observed on decreasing pH from near-neutral. Conversely, suspension stability was maintained on increasing pH from near-neutral. Likewise, flocculation could be quickly induced by the addition of salt and cationic surfactant in small amounts, but the suspensions displayed greater stability to anionic and non-ionic surfactant additives. These results have important implications for the successful formulation of complex fluids employing zwitterionic colloids. (c) 2012 Elsevier Inc. All rights reserved.
- URI
- https://www.sciencedirect.com/science/article/pii/S0021979712007734?via%3Dihubhttp://hdl.handle.net/20.500.11754/42947
- ISSN
- 0021-9797
- DOI
- 10.1016/j.jcis.2012.06.085
- Appears in Collections:
- GRADUATE SCHOOL[S](대학원) > BIONANOTECHNOLOGY(바이오나노학과) > Articles
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