RSC Publishing


Publishing

 

Cover image for Soft Matter, select for current issue

Soft Matter

Where physics meets chemistry meets biology for fundamental soft matter research.



Subscribers

Non-subscribers

Free access



Paper

Soft Matter, 2009, 5, 342 - 345, DOI: 10.1039/b807298a


Spontaneous homeotropic alignment in films of rigid–flexible polyelectrolyte complexes

Hayley A. Every, Leen van der Ham, Stephen J. Picken and Eduardo Mendes


Contrary to expectation, the electrostatic complexation of a rigid-rod anionic polyelectrolyte that exhibits nematic phase behaviour in aqueous solution with a flexible cationic polyelectrolyte forms homeotropically aligned films upon casting, i.e. the rigid molecules spontaneously align perpendicular to the substrate. Moreover, such alignment is retained upon the introduction of up to 10 mol% of a flexible cationic polyelectrolyte. The formation of a weak physical gel during film drying or in the precursor solution appears to be critical in facilitating homeotropic alignment in such films. Consequently, it can be envisaged that electrostatic complexation may be fine tuned in order to provide homeotropically aligned films of any rigid charged molecule.

Graphical abstract image for this article  (ID: b807298a)