Vertical liquid crystal orientation of phytochemical-based oryzanol modified polystyrene

Area of Science:

• Polymer Chemistry
• Materials Science
• Liquid Crystal Displays

Background:

• Liquid crystal (LC) displays rely on precise molecular alignment for optimal performance.
• Developing novel materials for LC orientation layers is crucial for advancing display technology.
• Phytochemicals offer a sustainable route for creating advanced polymer materials.

Purpose of the Study:

• To synthesize and characterize oryzanol-modified polystyrenes (PORZ) for LC orientation.
• To investigate the relationship between the oryzanol moiety's mole fraction and LC orientation behavior.
• To evaluate the electro-optical properties and stability of these novel materials as LC orientation layers.

Main Methods:

• Synthesis of phytochemical-based oryzanol-modified polystyrenes (PORZ) with varying mole fractions.
• Fabrication of LC cells using PORZ films.
• Measurement of surface energy and correlation with LC orientation.
• Assessment of electro-optical properties including thermal and UV stability, voltage holding ratio, and residual DC voltage.

Main Results:

• Increased mole fraction of oryzanol side groups promoted vertical LC orientation.
• Vertical orientation behavior was observed when polymer surface energy was below 40.42 mJ m^-2.
• PORZ100 demonstrated excellent aligning stabilities (250 °C, 20 J cm^-2 UV) and good electro-optical properties (voltage holding ratio, R-DC).

Conclusions:

• Oryzanol-modified polystyrenes are effective materials for controlling LC orientation.
• Surface energy is a key factor determining the vertical alignment behavior.
• PORZ100 shows promise as a stable, eco-friendly orientation layer for advanced LC applications.