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Complex fluids under microflow probed by SAXS: rapid microfabrication and analysis Complex fluids under microflow probed by SAXS: rapid microfabrication and analysis

DOI: 10.1088/1742-6596/247/1/012050 DOI Help

Authors: Hazel Martin (Imperial College London) , Nick Brooks (Imperial College London) , John Seddon (Imperial College London) , Nicholas Terrill (Diamond Light Source) , Paul Luckham (Imperial College London) , Adam Kowalski (Unilever Research & Development) , Joao Cabral (Imperial College London)
Co-authored by industrial partner: Yes

Type: Conference Paper
Conference: SAS 2009
Peer Reviewed: No

State: Published (Approved)
Published: November 2010

Abstract: We report a combined microfluidic and online synchrotron small-angle X-ray scattering (SAXS) study of complex surfactant mixtures under flow. We investigate the influence of a series of flow constrictions, generating well-defined, periodic extensional flow fields, on the microstructure of two model surfactant mixtures containing SDS and CTAC. Specifically, the lamella spacing, orientation and structural order are reported and correlated with the imposed flow field: geometry, flow velocity and residence time. The design, fabrication and operation of a microfluidic system using rapid prototyping is described in detail. We show that polydimethyl siloxane (PDMS), ubiquitous in microfabrication, provides a suitable matrix for SAXS microdevices provided that: (i) PDMS thickness are kept to a minimum while retaining structural integrity (~1000μm) and (ii) scattering from the structure of interest is sufficiently decoupled from the amorphous background scattering. The combination SAXS-microfluidics provides unprecedented opportunities to elucidate the non-equilibrium structure formation and relaxation of complex fluids, demonstrated here for concentrated surfactant mixtures.

Subject Areas: Physics


Instruments: I22-Small angle scattering & Diffraction