Lange T, Charton S, Bizien T, Testard F, Malloggi F. OSTE+ for in situ SAXS analysis with droplet microfluidic devices.
LAB ON A CHIP 2020;
20:2990-3000. [PMID:
32696785 DOI:
10.1039/d0lc00454e]
[Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
In recent years, microfluidic-based sample preparation techniques have emerged as a powerful tool for measurements at large scale X-ray facilities. Most often the microfluidic device was a form of hybrid system, i.e. an assembly of different materials, because a simple, versatile and inexpensive microfabrication method, on the one hand, and X-ray compatibility, on the other hand, cannot generally be achieved by the same material. The arrival of a new polymer family based on off-stoichiometric thiol-ene-epoxy (OSTE+) has recently redistributed the cards. In this context, we studied the relevance and the compatibility of OSTE+ for small-angle X-ray scattering (SAXS) studies. The material was characterized regarding its X-ray properties (transmission coefficient, attenuation coefficient, scattering pattern and polymer aging under X-ray light) and their comparison with those of the usual polymers used in microfluidics and/or for synchrotron radiation experiments. We show that OSTE+ has a better SAXS signal than polyimide, the polymer of reference in the SAXS community. Then a detailed protocol to manufacture a suitably thin full OSTE+ chip (total thickness <500 μm) is described and the potency of full OSTE+ devices for in situ SAXS studies is highlighted in two case-studies: the characterization of gold nanoparticles and the precipitation of cerium oxalate particles, both in moving droplets. Additionally, a method to analyze the scattering signals from droplet and carrier phase in a segmented flow is proposed.
Collapse