Nematic liquid crystal reorientation around multi-walled carbon nanotubes mapped via Raman microscopy

Area of Science:

• Materials Science
• Physics
• Nanotechnology

Background:

• Topological defects in liquid crystals (LCs) are crucial for their unique properties.
• Multiwalled carbon nanotubes (MWCNTs) can influence LC behavior due to their surface properties.
• External electric fields are known to reorient LC molecules.

Purpose of the Study:

• To investigate the formation and characteristics of topological defects in LC matrices induced by MWCNTs and electric fields.
• To understand the interplay between MWCNTs, electric fields, and LC molecular orientation.
• To spatially map and quantify the topological defects at microscale.

Main Methods:

• Macroscopic analysis using spectroscopic variable angle ellipsometry.
• Microscale analysis using confocal micro-Raman spectroscopy.
• Acquisition of a three-dimensional, spatially-resolved map of topological defects.

Main Results:

• Topological defects are formed due to the distortion of the LC molecular director near the MWCNT surface.
• Scale length variations and orientation topography of LC molecules around MWCNTs were determined.
• The study successfully mapped the 3D structure of the topological defects.

Conclusions:

• MWCNTs and electric fields synergistically induce and control topological defects in LC matrices.
• The findings provide insights into the microstructural organization of LCs influenced by nanomaterials.
• This research contributes to the understanding of LC-nanomaterial interactions for advanced applications.