Abstract
Hypothesis: Understanding the scission of rod-like micelles under mechanical forces is crucial for optimizing their stability and behavior in industrial applications. This study investigates how micelle length, flexibility, and external forces interact, offering insights into the design of micellar systems in processes influenced by mechanical stress. Although significant, direct experimental observations of flow-induced micellar scission using scattering techniques remain scarce. Experiments and Simulations: Small angle neutron scattering (SANS) is used to explore the shear response of aqueous cetyltrimethylammonium bromide (CTAB) solutions with sodium nitrate. Rheological tests show shear thinning with no shear banding, ensuring a uniform flow field for reliable interpretation of scattering data. As shear rate increases, the scattering spectra show angular distortion, which is analyzed using spherical harmonic decomposition to characterize flow-induced scission and micelle orientation under shear. Findings: Two analysis steps are used: a model-independent spectral eigendecomposition reveals a decrease in micellar length, while regression analysis quantifies the evolution of the length distribution and mean length with shear rate. Additionally, micelle alignment increases with shear, quantified by the orientational distribution function. These findings provide experimental evidence for flow-induced alignment and scission, offering a new framework for understanding shear-induced phenomena in micellar systems.
| Original language | English |
|---|---|
| Pages (from-to) | 1125-1134 |
| Number of pages | 10 |
| Journal | Journal of Colloid and Interface Science |
| Volume | 686 |
| DOIs | |
| State | Published - May 15 2025 |
Funding
A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. This research was sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U. S. Department of Energy. RPM acknowledges support from CHRNS, a national user facility jointly funded by the NCNR and the NSF under Agreement No. DMR-2010792. Commercial equipment or software identified in this work does not imply recommendation nor endorsement by NIST. GRH was supported by the National Science and Technology Council in Taiwan with Grant No. NSTC 111-2112-M-110-021-MY3. We would like to thank ILL for the provision of beam time on the D22 SANS instrument DOI: 10.5291/ILL-DATA.EASY-1399. A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. This research was sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy. RPM acknowledges support from CHRNS, a national user facility jointly funded by the NCNR and the NSF under Agreement No. DMR-2010792. Commercial equipment or software identified in this work does not imply recommendation nor endorsement by NIST. GRH was supported by the National Science and Technology Council in Taiwan with Grant No. NSTC 111-2112-M-110-021-MY3. We would like to thank ILL for the provision of beam time on the D22 SANS instrument DOI: https://doi.org/10.5291/ILL-DATA.EASY-1399.
Keywords
- Mechanically driven rod-like micellar solutions
- Real spherical harmonic expansion
- Small angle neutron scattering