Three-dimensional textures and defects of soft material layering revealed by thermal sublimation.
Layering is found and exploited in a variety of soft material systems, ranging from complex macromolecular self-assemblies to block copolymer and small-molecule liquid crystals. Because the control of layer structure is required for applications and characterization, and because defects reveal key features of the symmetries of layered phases, a variety of techniques have been developed for the study of soft-layer structure and defects, including X-ray diffraction and visualization using optical transmission and fluorescence confocal polarizing microscopy, atomic force microscopy, and SEM and transmission electron microscopy, including freeze-fracture transmission electron microscopy. Here, it is shown that thermal sublimation can be usefully combined with such techniques to enable visualization of the 3D structure of soft materials. Sequential sublimation removes material in a stepwise fashion, leaving a remnant layer structure largely unchanged and viewable using SEM, as demonstrated here using a lamellar smectic liquid crystal.
Graduate School of Nanoscience and Technology and KINC, and National Research Laboratory for Organic Opto-Electronic Materials, Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea.
Dong Ki
DK
Yoon
Yun Ho
YH
Kim
Dae Seok
DS
Kim
Seong Dae
SD
Oh
Ivan I
II
Smalyukh
Noel A
NA
Clark
Hee-Tae
HT
Jung
D021621:Imaging, Three-Dimensional / Q000379:methods*; D050866:Liquid Crystals / Q000737:chemistry; D008422:Materials Testing / Q000379:methods*; D018625:Microscopy, Atomic Force; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D049329:Nanostructures / Q000648:ultrastructure*; D013499:Surface Properties; D013818:Thermogravimetry; D014961:X-Ray Diffraction
direct visualization; sublime