Homogeneous alignment

In liquid crystals homogeneous alignment, sometimes called planar alignment, is the state of alignment where molecules align in parallel to a substrate. The opposite method is homeotropic alignment.¹

For planar alignment - polyimides can be used. One of the popular ones is PI-2555.

The surface has to be rubbed by paper or by a velvet or similar cloth in order to make the alignment axis parallel to the rubbing.¹ However the exact mechanism of this alignment is not entirely clear.

References

Jones, Lesley Parry (2012), Chen, Janglin; Cranton, Wayne; Fihn, Mark (eds.), "Alignment Properties of Liquid Crystals", Handbook of Visual Display Technology, Berlin, Heidelberg: Springer Berlin Heidelberg, pp. 1390–92, doi:10.1007/978-3-540-79567-4_86, ISBN 978-3-540-79566-7, retrieved 2025-01-08{{citation}}: CS1 maint: work parameter with ISBN (link)

[:0-1] Jones, Lesley Parry (2012), Chen, Janglin; Cranton, Wayne; Fihn, Mark (eds.), "Alignment Properties of Liquid Crystals", Handbook of Visual Display Technology, Berlin, Heidelberg: Springer Berlin Heidelberg, pp. 1390–92, doi:10.1007/978-3-540-79567-4_86, ISBN 978-3-540-79566-7, retrieved 2025-01-08{{citation}}: CS1 maint: work parameter with ISBN (link)

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