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Second-harmonic generation from rubbed ferroelectric liquid crystal mesogenic monolayer surfaces
C S Park1, T E Furtak, N A Clark
1Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
Summary
We developed novel self-assembled monolayers that align liquid crystals on glass surfaces. This surface treatment induces a single domain, crucial for advanced display technologies.
Area of Science:
- Materials Science
- Surface Chemistry
- Liquid Crystal Physics
Background:
- Controlling liquid crystal alignment is vital for display technologies.
- Traditional alignment methods like polymer rubbing have limitations.
Purpose of the Study:
- To design and characterize self-assembled monolayers (SAMs) for liquid crystal alignment.
- To investigate the mechanism of rubbing-induced alignment using SAMs.
Main Methods:
- Fabrication of SAMs with ferroelectric liquid crystal mesogens on glass.
- Mechanical rubbing of the SAMs.
- Optical second-harmonic generation (SHG) for surface analysis.
Main Results:
- Rubbed SAMs induced single-domain alignment in a high-polarization achiral liquid crystal (smectic-C phase).
- SHG confirmed rubbing-induced in-plane anisotropy in mesogen orientation.
- Achieved a surface order parameter of 0.094, comparable to polymeric alignment layers.
Conclusions:
- SAMs offer an effective alternative to polymeric layers for liquid crystal alignment.
- The study elucidates the role of surface anisotropy in achieving uniform alignment.