Direct Visualization of the Perforated Layer/Gyroid Grain Boundary in a Polystyrene-block-polyisoprene/polystyrene Blend by Electron Tomography

Abstract

Morphology of grain boundaries observed during order-order transition at the perforated layer (PL)/gyroid interface was investigated by electron tomography in a polystyrene-block-polyisoprene (SI)/polystyrene (hS) blend. As a general result, 3D analysis shows the nonrelated orientation of the growing gyroid phase relative to the consumed PL grain: a nonepitaxial transition. This is a predictable result due to the nucleation of PL and gyroid grains in the sponge phase, with random orientation. In few cases, however, epitaxy was observed with part of the PL phase orientation conserved by the growing gyroid, a rare situation potentially resulting from the nucleation of the gyroid grain into the PL phase, or from the lucky match between both grain orientations. For both epitaxial and nonepitaxial grain boundaries, the PI and PS phases were found continuous through the grain boundary. For nonepitaxial transitions, connections were observed at the grain boundary between the otherwise independent PI gyroid networks. These networks remain independent through epitaxial transitions, each of them being connected, with a regular pattern, to one out of two perforated layers. With clarification of these complex morphologies, electron tomography demonstrates again its usefulness for polymer science.

High-resolution three-dimensional probes of biomaterials and their interfaces

“…In standard TEM, bright-field (BF) images can make up the tilt series; these types of images reveal shape-sensitive information in three dimensions [6]. While BF TEM tomography is ideally suited for purely biological specimens and samples containing polymer-based biomaterial interfaces [14], the introduction of a crystalline material (such as some biomaterials) results in diffraction contrast and Fresnel fringes that severely degrade the accuracy of the reconstruction [13]. Another form of microscopy, scanning transmission electron microscopy (STEM), which uses a focused probe rastering the sample, may alleviate these problems.…”

Simulation of local ion transport in lamellar block copolymer electrolytes based on electron micrographs

“…One possibility is that local ion transport is fundamentally different in 2D and 3D and thus one needs to image and simulate 3D morphologies. While considerable work will be required to examine this possibility, it can readily be done as 3D morphology can be determined by electron tomography . However, given the fact that our 2D results were in good agreement with effective medium theory, it is unlikely that the 3D results will differ significantly from that theory.…”

Exploring Hidden Local Ordering in Microemulsions with a Weak Directive Second Order Parameter

“…So far, all known studies of domain alignment took place at planar surfaces with single philicity [15][16][17]21] including the current one. However, for diblock copolymers relative orientations of ordered domains are studied at grain boundaries [10,11]. The next step of textured surfaces is left for future works.…”

“…vectorial or tensorial) order parameter in order to describe the thermodynamics of complicated ordering phenomena and responses to directed external fields of soft matter systems. Contrarily, for diblock copolymers [9] (Grain boundaries of diblock copolymers have been analyzed experimentally [10,11]) and microemulsions [12][13][14], a wide range of phenomena can be explained on the basis of a single order parameter describing the local concentration of one species versus the other, i.e. monomer A vs. B or water vs. oil.…”