Structure, dynamics and phase behavior of short rod inclusions dissolved in a colloidal membrane

• Published in: Soft matter Vol. 15; no. 35; pp. 733 - 742
• Main Authors: Siavashpouri, Mahsa, Sharma, Prerna, Fung, Jerome, Hagan, Michael F, Dogic, Zvonimir
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 21.09.2019
• Subjects: Anchoring; Assembly; Bilayers; Binary mixtures; Colloids; Composite materials; Composite structures; Inclusions; Membranes; Rods
• ISSN: 1744-683X; 1744-6848
• DOI: 10.1039/c9sm01064e

Inclusions dissolved in an anisotropic quasi-2D membrane acquire new types of interactions that can drive assembly of complex structures and patterns. We study colloidal membranes composed of a binary mixture of long and short rods, such that the length ratio of the long to short rods is approximately two. At very low volume fractions, short rods dissolve in the membrane of long rods by strongly anchoring to the membrane polymer interface. At higher fractions, the dissolved short rods phase separate from the background membrane, creating a composite structure comprised of bilayer droplets enriched in short rods that coexist with the background monolayer membrane. These results demonstrate that colloidal membranes serve as a versatile platform for assembly of soft materials, while simultaneously providing new insight into universal membrane-mediated interactions. Short-rod inclusions dissolved in an anisotropic quasi-2D colloidal membrane anchor to the membrane-polymer interface and acquire new types of interactions that drive bulk phase separation and assembly of complex structures and patterns.