2 research outputs found
Solid-Supported Lipid Multilayers under High Hydrostatic Pressure
In this work, the structure of solid-supported
lipid multilayers
exposed to increased hydrostatic pressure was studied <i>in situ</i> by X-ray reflectometry at the solid–liquid interface between
silicon and an aqueous buffer solution. The layers’ vertical
structure was analyzed up to a maximum pressure of 4500 bar. The multilayers
showed phase transitions from the fluid into different gel phases.
With increasing pressure, a gradual filling of the sublayers between
the hydrophilic head groups with water was observed. This process
was inverted when the pressure was decreased, yielding finally smaller
water layers than those in the initial state. As is commonly known,
water has an abrasive effect on lipid multilayers by the formation
of vesicles. We show that increasing pressure can reverse this process
so that a controlled switching between multi- and bilayers is possible
Transmission Surface Diffraction for Operando Studies of Heterogeneous Interfaces
Processes
at material interfaces to liquids or to high-pressure
gases often involve structural changes that are heterogeneous on the
micrometer scale. We present a novel in situ X-ray scattering technique
that uses high-energy photons and a transmission geometry for atomic-scale
studies under these conditions. Transmission surface diffraction gives
access to a large fraction of reciprocal space in a single acquisition,
allowing direct imaging of the in-plane atomic arrangement at the
interface. Experiments with focused X-ray beams enable mapping of
these structural properties with micrometer spatial resolution. The
potential of this new technique is illustrated by in situ studies
of electrochemical surface phase transitions and deposition processes