Effect of surface condition on liquid crystal photoalignment by light-induced azo dye adsorption phenomena

ABSTRACT

The effect of surface condition on the photoalignment of light-induced methyl red (MR) adsorption phenomena on various substrates based on azo dye-doped liquid crystals is investigated. The results show that the polar surface energy determines the initiation of MR adsorption phenomena. The surface polarity energy of different substrates, which are modulated by oxygen plasma treatment (OPT), is further examined using the sessile drop method. The results also indicate that the uniformity and efficiency of MR adsorption can be enhanced by OPT. Light intensity influences the MR adsorption rate. The uniformity of MR adsorption onto various substrates is analysed via polarised optical microscopy.

Graphical Abstract

KEYWORDS:

• Liquid crystals
• azo dye
• adsorption
• photoalignment
• surface tension

Acknowledgements

The authors would like to thank the Ministry of Science and Technology (MOST) of Taiwan for financially supporting this research under Grant Nos. MOST 101-2112-M-006-011-MY3 and MOST 103-2112-M-008-018-MY3. We sincerely thank the reviewer for the valuable comments and suggestions.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors would like to thank the Ministry of Science and Technology (MOST) of Taiwan for financially supporting this research under Grant Nos. MOST 101-2112-M-006-011-MY3 and MOST 103-2112-M-008-018-MY3.