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Updated: Dec 13, 2025
Combining Microfluidics and Microrheology to Determine Rheological Properties of Soft Matter during Repeated Phase Transitions
Published on: April 19, 2018
Microrheology to probe smectic clusters in bent-core nematic liquid crystals
Sathyanarayana Paladugu1, Supreet Kaur2, Golam Mohiuddin2
1School of Physics, University of Hyderabad, Hyderabad, India. sathyapaladugu@gmail.com sdsp@uohyd.ernet.in and Soft and Active Matter Group, Department of Physics, Indian Institute of Science Education and Research (IISER), Tirupati, Andhra Pradesh 517507, India.
Bent-core liquid crystals with smectic clusters show unique properties. Microrheology reveals these clusters significantly impact shear modulus, offering insights into their behavior.
Area of Science:
- Materials Science
- Soft Matter Physics
- Liquid Crystal Physics
Background:
- Bent-core nematic liquid crystals possess unusual physical properties.
- These properties are often attributed to the presence of cybotactic (smectic) clusters within the nematic phase.
Purpose of the Study:
- To investigate the influence of smectic clusters on the complex shear modulus (G*(ω)) of asymmetric bent-core liquid crystals.
- To correlate microrheological findings with curvature elastic constant measurements.
Main Methods:
- Utilized microrheology to study the complex shear modulus (G*(ω)) of two asymmetric bent-core liquid crystals.
- Investigated compounds with different hydrocarbon chain lengths (8OCH3 and 16OCH3) exhibiting distinct phase behaviors (nematic only vs. nematic and smectic-A).
Main Results:
- Observed distinct directional shear modulus in the 16OCH3 compound (exhibiting smectic-A and nematic phases) compared to the 8OCH3 compound (nematic only).
- The difference in shear modulus was attributed to the presence of smectic clusters, particularly near the smectic-A to nematic phase transition.
- Estimated the approximate size of these smectic clusters using a simplified model.
Conclusions:
- Microrheological studies are effective for characterizing smectic clusters in bent-core nematic liquid crystals.
- The presence and influence of cybotactic clusters significantly alter the rheological properties of these materials.
