Fast Diffusion-Limited Lyotropic Phase Transitions Studied in-situ Using Continuous Flow Microfluidics / Microfocus-SAXS
2014 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 30, no 42, 12494-12502 p.Article in journal (Refereed) Published
Fast concentration-induced diffusion-limited lyotropic phase transitions can be studied in situ with millisecond time resolution using continuous flow microfluidics in combination with microfocus small-angle X-ray scattering. The method was applied to follow a classical self-assembly sequence where amphiphiles assemble into micelles, which subsequently assemble into an ordered lattice via a disorder/order transition. As a model system we selected the self-assembly of an amphiphilic block copolymer induced by the addition of a nonsolvent. Using microchannel hydrodynamic flow-focusing, large concentration gradients can be generated, leading to a deep quench from the miscible to the microphase-separated state. Within milliseconds the block copolymers assembly via a spinodal microphase separation into micelles, followed by a disorder/order transition into an FCC liquid-crystalline phase with late-stage domain growth and shear-induced domain orientation into a mesocrystal. A comparison with a slow macroscopic near-equilibrium kinetic experiment shows that the fast structural transitions follow a direct pathway to the equilibrium structure without the trapping of metastable states.
Place, publisher, year, edition, pages
American Chemical Society (ACS), 2014. Vol. 30, no 42, 12494-12502 p.
X-RAY-SCATTERING, BLOCK-COPOLYMERS, POLYMERS, STATE, CHIP
IdentifiersURN: urn:nbn:se:kth:diva-180263DOI: 10.1021/la502971mISI: 000347744100005ScopusID: 2-s2.0-84908343194OAI: oai:DiVA.org:kth-180263DiVA: diva2:891991
FunderKnut and Alice Wallenberg Foundation
QC 2016-01-182016-01-082016-01-082016-01-18Bibliographically approved