In situ observation of self-assembly of sugars and surfactants from nanometres to microns

Abstract

The hierarchical self-assembly of sugar and surfactant molecules into hollow tubular microstructures was characterized in situ with high resolution small-angle X-ray scattering spanning more than three orders of magnitude of spatial scales. Scattering profiles reveal that aqueous host-guest inclusion complexes self-assemble into multiple equally spaced curved bilayers forming a collection of concentric hollow cylinders. Scattering data can be described by a simple theoretical model of the microtubes. The interlamellar distance was found to be surprisingly large. Moreover, we report that the multi-walled structure of the microtubes swells as the concentration or the temperature is varied.

A multipurpose instrument for time-resolved ultra-small-angle and coherent X-ray scattering

“…USAXS and SAXS elucidated the structure from the whole cell to the ultrastructure of the cell membrane, providing complementary information to both optical and cryo-electron microscopies. Another notable example is an investigation of the hierarchical structure of microtubes formed by the self-assembly of an archetypical surfactant, sodium dodecyl sulfate (SDS), and a naturally abundant polysaccharide, -cyclodextrin (Ouhajji et al, 2017). In this case, the combination of SAXS/USAXS revealed the multiscale structure from their molecular capsids to folded microtubes.…”

Wet-Chemical Synthesis of Chiral Colloids

“…Upon cooling to room temperature these SDS@2β-CD complexes self-assemble into multiple equally spaced curved bilayers forming a set of concentric hollow cylinders. 20 These cylinders are straight and rigid tubes that can be several tens of micrometers long with a pore diameter of 0.9 μm ± 10%. On addition of colloidal spheres, the tubular structures act as a cylindrically confining environment and ordered, chainlike colloid-in-tube assemblies are obtained.…”

Synchrotron Scattering Methods for Nanomaterials and Soft Matter Research

“…Combined SAXS and WAXS revealed the hierarchical morphology of molten and semicrystalline vitrimers [38]. A spectacular case is the hierarchical organization of certain amphiphilic molecules to form well-defined nanotubes [39,40] and microtubes [41], which can be unraveled by SAXS. For example, the nanotubes formed by some amphiphilic peptides such as amyloid β-peptide, which display multiple structural levels from the molecular scale up to the long range ordering of nanotubes [3].…”

“…Such systems offer the possibility for rational design of lyotropic phases suitable for investigating enzymatic studies, drug encapsulation, therapeutic delivery, etc. A spectacular example of thermally controlled hierarchical self-assembly has been revealed in a relatively simple system composed of a naturally abundant circular polysaccharide β-cyclodextrin (β-CD) and surfactant SDS (in 2:1 molar ratio) resulting in hierarchically organized microtubes of macroscopic dimension [41,73]. The self-assembly is induced by cooling the solution from 75 • C to 25 • C and SAXS revealed the in-plane ordering of the SDS-cyclodextrin capsids, the lamellar staking of the membranes and USAXS elucidated the structure of microtubes.…”