I am trapping a 1-3 um sized silica particle in water. The viscosity obtained from auto correlation function is coming out double that of viscosity of water at 20 degree Celsius. Can that happen and what are the possible causes behind it?
Yes, it is possible for the measured viscosity of a suspension to be higher than the viscosity of the solvent due to various factors, such as the presence of particles, interparticle interactions, and confinement effects.
In the case of trapping a silica particle in water, the particle can cause a disturbance to the surrounding water molecules, leading to changes in the local viscosity of the suspension. The viscosity increase can be attributed to several factors, such as the size, shape, and surface properties of the particle, as well as the concentration of particles in the suspension. For example, the presence of a large particle can lead to the formation of a local region of higher viscosity due to the confinement of the surrounding water molecules.
Additionally, the interparticle interactions can play a role in determining the viscosity of the suspension. In a dilute suspension, the interactions between particles may be negligible, but in a concentrated suspension, the particles can interact with each other, leading to changes in the rheological properties of the suspension.
Finally, it is important to consider the experimental setup and conditions. The presence of any artifacts, such as air bubbles or contamination, can affect the measurement of the viscosity. Additionally, variations in temperature or pressure can also affect the viscosity measurement.
In summary, the observed increase in viscosity compared to the viscosity of water at 20 degrees Celsius may be due to the presence of the silica particle, interparticle interactions, and/or experimental artifacts. It is important to carefully consider all these factors when interpreting the viscosity measurements of a suspension.
No, the viscosity of water in optical trapping cannot come out double than that of bulk viscosity. Optical trapping relies on the interaction between the light and the particles being trapped, and the viscosities of the surrounding media do not affect the trapping process.
- Badges
- Science topic