Simultaneous formation behaviour of surface structures and molecular alignment by patterned photopolymerisation

ABSTRACT

Highly functional soft materials with fine control of molecular alignment are of great interest for the applications in various fields. However, the current method of molecular alignment still has some challenges. Recently, we have developed a new alignment process based on a concept of scanning wave photopolymerisation (SWaP). When a sample is irradiated with spatially selected light, a polymerisation occurs only in an irradiated region, leading to a molecular motion between the irradiated and unirradiated regions. Such molecular motion generates the alignment of liquid crystal molecules. Moreover, a surface relief structure is formed in the polymer film by the molecular motion. In this study, we simultaneously formed the surface structure and molecular alignment by the patterned photopolymerisation. We compared the degree of molecular alignment with the shape of the created surface structure, and revealed that the degree of molecular alignment was maximized at the boundary of irradiated and unirradiated regions. This method enables one to form both molecular alignment patterning and surface structuring in a single step.

Graphical abstract

KEYWORDS:

• Liquid crystal
• photopolymerisation
• molecular alignment
• surface profile

Acknowledgments

This work was supported by JSPS KAKENHI grant no. JP18H05422 in Scientific Research on Innovative Areas “Molecular Engine: Design of Autonomous Functions through Energy Conversion.” This work was supported by the Core Research for Evolutional Science and Technology (CREST) program, “Creation of Innovative Core Technologies for Nano-enabled Thermal Management” (no. JPMJCR18I4) and JST. This work was supported by JSPS KAKENHI Grant Numbers JP18K14297, JP18J15144. This work was performed under the Cooperative Research Program of “Network Joint Research Centre for Materials and Devices.” This work was performed under the Research Program for CORE Labs of “Network Joint Research Centre for Materials and Devices.”

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Core Research for Evolutional Science and Technology [JPMJCR18I4];Japan Society for the Promotion of Science [JP18H05422, JP18J15144, JP18K14297];