Abstract
Lamellar structures are formed in a variety of soft materials including lipids, surfactants, block polymers, clays, colloids, semicrystalline polymers and others. Lamellar phases are characterized by scattering patterns containing pseudo-Bragg peaks from the layer ordering. However, fluctuations of the lamellae give rise to diffuse scattering in addition. This diffuse scattering can provide valuable information on the elastic properties of lamellae which control their fluctuations. A number of models to account for this are described in this Tutorial Review, along with examples from the literature. In addition, diffuse scattering from in-plane fluctuations or structures such as perforations or patterned nanoparticles is considered. This type of diffuse scattering can give unique information on the nature of, and positional (and bond orientational) ordering within, correlated structures within the lamellar plane. Anisotropic diffuse scattering features from thermotropic smectic phases is also briefly discussed.
Highlights
IntroductionDiffuse scattering results from aperiodic or imperfectly periodic ordering in a material and produces broad features in measured scattering patterns
Lamellar structures are layered phases formed by a range of soft materials including lipids and surfactants, block polymers, clays, colloids, crystallized polymers and others.[1,2,3,4,5] Lamellar phases have the same symmetries as smectic phases formed by thermotropic liquid crystals, which are solvent-free phases of mesogenic molecules, in the sense of Professor Ian W
In reality the intensity and/or width of diffraction peaks is found to change with the diffraction order, and this is described by several models detailed below
Summary
Diffuse scattering results from aperiodic or imperfectly periodic ordering in a material and produces broad features in measured scattering patterns This review discusses such scattering and includes examples from experimental observations, along with descriptions and examples of calculations using a selection of models. It gives significant broad scattering features that have been reported for lamellar phases formed by surfactants and lipids in aqueous solution, block polymer melts and semicrystalline block polymers This Tutorial Review is organized as follows. Alignment is a useful method to increase the information content from oriented scattering patterns and may be achieved in lamellar phases using shear, or magnetic or electric fields This is highlighted by an example whereby a structure factor for aligned lipids is used to obtain unique information on the layer fluctuations and elasticity. It does not consider diffuse scattering that arises from form factor effects, for example lipid membrane form factors.[18,19]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
