Π-GISANS: probing lateral structures with a fan shaped beam

Abstract

We have performed grazing incidence neutron small angle scattering using a fan shaped incident beam focused along one dimension. This allows significantly reduced counting times for measurements of lateral correlations parallel to an interface or in a thin film where limited depth resolution is required. We resolve the structure factor of iron inclusions in aluminium oxide and show that the ordering of silica particles deposited on a silicon substrate depends on their size. We report hexagonal packing for 50 nm but not for 200 nm silica spheres deposited by a modified Langmuir-Schaefer method on a silicon substrate. For the 200 nm particles we extract the particles shape from the form factor. Moreover, we report dense packing of the particles spread on a free water surface. We name this method π-GISANS to highlight that it differs from GISANS as it gives lateral information while averaging the in-depth structure.

Structural Characterization of Nanoparticle-Supported Lipid Bilayer Arrays by Grazing Incidence X-ray and Neutron Scattering

“…25−27 Furthermore, Langmuir transfer techniques have the advantage of yielding large uniform monolayers, which make well-suited samples for characterization by fluxlimited grazing incidence scattering methods such as neutron reflectometry (NR) and grazing incidence neutron small-angle scattering (GISANS). 28,29 Due to their unique ability to probe noninvasively buried interfaces and their differential sensitivity toward hydrogen and deuterium, neutrons are among the most powerful surface-sensitive techniques for the structural characterization of complex biological thin films at solid/liquid interfaces, of which SLBs represent a primary example. Grazing incidence neutron scattering, particularly NR, has found wide application in the structural characterization of planar SLBs; however, the potential of techniques like GISANS, as well as NR, remains largely untapped when it comes to structural studies of model membranes with a more complex morphology.…”

“…Several top-down approaches rely on nanolithography techniques, which afford a high degree of control and fine-tuning over the resulting surface structure. , The high precision of top-down methods however often comes at the cost of time and resources, which can become limiting factors when dealing with large surfaces and number of substrates to functionalize. Bottom-up approaches, on the other hand, typically rely on self-assembly processes driven by chemical and physical forces and can be exploited to fabricate patterned samples using nanoparticles (NP) to serve as substrates for SLB formation. ,, Among bottom-up methods employed to form large arrays of NPs, Langmuir–Blodgett and Langmuir–Schaefer depositions offer an additional level of control on the self-assembly process by enabling the adjustment of the packing density of the Langmuir monolayer at the air/water interface prior to its transfer onto a solid substrate. − Furthermore, Langmuir transfer techniques have the advantage of yielding large uniform monolayers, which make well-suited samples for characterization by flux-limited grazing incidence scattering methods such as neutron reflectometry (NR) and grazing incidence neutron small-angle scattering (GISANS). , Due to their unique ability to probe noninvasively buried interfaces and their differential sensitivity toward hydrogen and deuterium, neutrons are among the most powerful surface-sensitive techniques for the structural characterization of complex biological thin films at solid/liquid interfaces, of which SLBs represent a primary example. Grazing incidence neutron scattering, particularly NR, has found wide application in the structural characterization of planar SLBs; however, the potential of techniques like GISANS, as well as NR, remains largely untapped when it comes to structural studies of model membranes with a more complex morphology.…”

Structural Characterisation of Nanoparticle-Supported Lipid Bilayers by Grazing Incidence X-ray and Neutron Scattering

“…Amongst bottom-up methods employed to form large arrays of NPs, Langmuir-Blodgett and Langmuir-Schaefer depositions offer an additional level of control on the self-assembly process by enabling the adjustment of the packing density of the Langmuir monolayer at the air/water interface prior to its transfer onto a solid substrate (15)(16)(17). Furthermore, Langmuir transfer techniques have the advantage of yielding large uniform monolayers which make well-suited samples for characterization by flux-limited grazing incidence scattering methods such as neutron reflectometry (NR) and grazing incidence neutron small angle scattering (GISANS) (18,19). Due to their unique ability to probe non-invasively buried interfaces and their differential sensitivity towards hydrogen and deuterium, neutrons are amongst the most powerful surface sensitive techniques for the structural characterization of complex biological thin films at solid/liquid interfaces, of which SLBs represent a primary example.…”