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In this work, the authors succeed in direct visualization of the network structure of synthetic hydrogels with transmission electron microscopy (TEM) by developing a novel staining and network fixation method. Such a direct visualization is not carried out because sample preparation and obtaining sufficient contrast are challenging for these soft materials. TEM images reveal robust heterogeneous network architectures at mesh size scale and defects at micro-scale. TEM images also reveal the presence of abundant dangling chains on the surface of the hydrogel network. The real space structural information provides a comprehensive perspective that links bulk properties with a nanoscale network structure, including fracture, adhesion, sliding friction, and lubrication. The presented method has the potential to advance the field.

The three-dimensional (3D) confinement effect on the microphase-separated structure of a diblock copolymer was investigated both experimentally and computationally. Block copolymer nanoparticles were prepared by adding a poor solvent into a block copolymer solution and subsequently evaporating the good solvent. The 3D structures of the nanoparticles were quantitatively determined with transmission electron microtomography (TEMT). TEMT observations revealed that various complex structures, including tennis-ball, mushroom-like, and multipod structures, were formed in the 3D confinement. Detailed structural analysis, showed that one block of the diblock copolymer slightly prefers to segregate into the particle surface compared with the other block. The observed structures were further elaborated using cell dynamics computer simulation

A simple fabrication method is demonstrated for surface-enhanced Raman scattering (SERS)-active plasmonic nanoballs, which consisted of Au nanoparticles (NPs) and core–shell polystyrene and amino-terminated poly(butadiene) particles, by heterocoagulation and Au NP diffusion. The amount of Au NPs introduced into the core–shell particles increases with the concentration of Au NPs added to the aqueous dispersion of the core–shell particles. When the amount of Au NPs increases, closely packed, three-dimensionally arranged and close-packed Au NPs arrays are formed in the shells. Strong SERS signals from para -mercaptophenol adsorbed onto composite particles with multilayered Au NPs arrays are obtained by near-infrared (NIR) light illumination.

Block copolymer nanopaticles were prepared from the mixture solutions containing good/poor solvents by a simple evaporation process. The block copolymers formed disorder, unidirectionally stacked lamellar, and onion-like structures in nanoparticles depending on preparation temperatures. Thermal annealing induced the disorder-order phase transition and order-order phase transformation in the block copolymer nanoparticles, even though the annealing temperature is lower than the of one polymer segment. The unusual thermal behaviors suggest that the glass transition temperature of the block copolymer is decreased by the effect of nanoparticle, whose surface areas are larger than their volumes.

The scarcity of oil resources is going to become one of the main factors threatening the stability of the global economy. To avoid an energy crisis in the future, it is essential to increase oil extraction in much deeper wells, experiencing higher temperatures and pressures. Exploring these deeper areas will demand novel and robust materials. Rubber sealants, or O-rings, are especially key components in enabling the probing and production of oil in deeper wells, so that higher temperature and pressure reservoirs are reached. In this account, it is demonstrated that carbon nanotubes homogeneously and randomly dispersed in rubber matrices, are able to generate durable sealants that operate satisfactorily at extremely high temperatures and pressures (e.g., 260 °C and 239 MPa). The key issues in these novel composites are: i) the nanotube surface-control and reactivity, ii) the used of multi-walled carbon nanotubes (MWNTs)-embedded in fluorinated rubber, and iii) the formation of a cellulation structure. This rubber nanocomposite with a cellulation structure and having extreme performance leads to a balanced pressure resistance, sealing ability, thermal resistance, and durability, which can contribute to doubling the current average global oil recovery efficiency.

Highly porous nanoscale structures are critical for a range of emerging technologies. Prominent examples include semiconductor devices, sensors, separations, supports for catalyst, and photonic devices. Recently, we demonstrated that it is feasible to directly pattern sub-100 nm features with high fidelity into porous spin-on organosilicate glass (SOG) materials using nanoimprint lithography (NIL). This novel use of the NIL technology was motivated by the enormous cost savings that could be realized by directly patterning the interlayer dielectric (ILD) material suitable for semiconductor interconnect structures. Directly creating the pattern in the functional material eliminates the subsequent processing steps that are normally required to the transfer the sacrificial resist pattern into the functional material. This has the potential to greatly reduce the Back-End-Of-The-Line (BEOL) manufacturing costs. Some of these eliminated steps, such as the photoresist etching and ashing, are especially harmful to porous dielectrics with interconnected pore networks because the etching byproducts can diffuse into and contaminate the interior regions of the porous material. However, a new concern with the direct imprinting of the ILD material is that the patterns are essentially used ‘‘as-imprinted’’. If the imprinting process affects the key properties of the functional material, the performance of the

The lamellar morphology in banded spherulites of poly(e-caprolactone) blended with an amorphous polymer, poly(vinyl butyral), was investigated by three-dimensional transmission electron tomography. It showed a local lamellar twist on a smaller scale than the band spacing by 2 orders of magnitude. It also indicated wavy lamellae and frequent variation in the direction of the lamellar plane. All these results indicated an S-profiled lamellar structure; that is, the cross section perpendicular to the lamellar growth direction was S-shaped. S-profiled lamellae show these structures when they are sliced at a certain angle to the lamellar surface direction. Lamellar branching was also observed, but no screw dislocations that led to the formation of extinction rings were observed in this work. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1122–1125, 2007

A three-dimensional (3D) lamellar structure of a poly(styrene-block-isoprene) block copolymer was observed at submicrometer and micrometer levels by scanning electron microscopy combined with a focused ion beam (FIB–SEM). The 3D lamellar structure with an exceptionally large periodicity, about 0.1 μm, was successfully reconstructed, and the size of the reconstructed image by FIB–SEM was 6.0 × 6.0 × 4.0 μm3, which was greater than the transmission electron microtomography data, 3.8 × 3.9 × 0.24 μm3, by a factor of about 40. This result indicates that 3D reconstruction using FIB–SEM is quite useful for direct 3D observations, especially analyses of polymeric materials at the submicrometer and micrometer levels. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 677–683, 2007

The grain boundary morphology of a cylinder-forming poly(styreneblock-isoprene) (SI) diblock copolymer was investigated using transmission electron microtomography (TEMT). The three-dimensional (3D) morphologies of the grain boundaries between the two grains with different orientation angle, α, were investigated. In the present study, two kinds of grain boundary morphologies, α ≃ 90° and α ≃ 120°, were examined in 3D. It was found that, in the case of α ≃ 90°, most of the cylindrical domains bent at the grain boundary in order not to intersect each other, while the cylindrical domains were found to be smoothly connected and were continuous in the case of α ≃ 120°. The observed morphologies indicated that the chain conformation inside the cylindrical microdomains plays more significant role than the segmental interaction between the two blocks.

Coexisting bicontinuous morphologies, one ordered and one disordered, are investigated in a macrophase-separated poly(styrene-block-isoprene) diblock copolymer/ homopolystyrene (SI/hS) blend. Two-phase behavior is attributed to the relatively high hS/S mass ratio (0.92). According to its crystallographic signature and channel coordination as discerned from three-dimensional (3D) images generated by transmission electron microtomography (TEMT), the ordered morphology is classified as gyroid. The 3D local and global topological characteristics of both bicontinuous morphologies as measured directly from TEMT images are reported. The disordered morphology is further compared with molecular-field simulations to ascertain the spatial distribution of the constituent species within the blend, thereby demonstrating the utility of high-resolution 3D imaging coupled with molecular-level simulations.

Three-dimensional (3D) image patterns of phase-separated poly(methyl methacrylate) (PMMA)/poly(styrene-ran-4-bromostyrene) (PS-Br) blends heated at 180°C for 6, 8, and 10 h were observed by 3D NMR microscopy with 3D X-ray microscopy in order to characterize the 3D structure of the polymer blends using a standard 3D reconstruction protocol program for obtaining the 3D digital array of the PS-Br/PMMA morphologies. The phase-separated structure of the polymer blends in several 10-μm scales was reasonably characterized. The phase-separated structure of polymer blends by 3D NMR images was quantitatively consistent with that by 3D X-ray images. It can be said that 3D NMR microscopy is a very useful means for analyzing the 3D structure of phase-separated polymer blends as well as 3D X-ray images. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 470–475, 2007

Structural deformation of phase-separated methylsiloxane gel under the influence of a surface has been studied. Competitive wetting of siloxane gel phase on a surface during phase formation is found to significantly affect the final morphology in a confined space. When the spinodal wavelength is sufficiently shorter than the size of the available space, a uniform bicontinuous structure forms in confined geometry. However, gel skeletons in the vicinity of a surface are elongated with decreasing size of the space, and finally when the size of the space becomes shorter than the spinodal wavelength, all the gel phase wets on a surface, showing a "wetting transition". Homogeneous bicontinuous methylsiloxane gels were successfully prepared, avoiding such structural deformation, in a long cylindrical fused silica capillary and used for capillary HPLC. The capillary gels exhibited excellent separation efficiency of nitrobenzenes and it was found that the surface character can be altered by incorporating surfactants, which will enable more advanced and extended control of surface character, depending on the analytes.

Understanding the vertical phase separation of donor and acceptor compounds in organic photovoltaics is requisite for the control of charge transport behavior and the achievement of efficient charge collection. Here, the vertically phase-separated morphologies of poly(3-hexylthiophene):[6,6]phenyl-C61-butyric acid methyl ester (P3HT:PCBM) blend films are examined with transmission electron microtomography, dynamic secondary ion mass spectroscopy, and X-ray photoelectron spectroscopy. The 3D morphologies of the processed films are analyzed and how the solvent additive causes vertical segregation is determined. The photocurrent–voltage characteristics of the vertically segregated blend films are strongly dependent on the 3D morphological organization of the donor and acceptor compounds in the photoactive layer. This dependence is correlated with asymmetric carrier transport at the buried interface and the air surface in the vertically segregated blend films.