Coupling of Microphase Separation and Dewetting in Weakly Segregated Diblock Co-polymer Ultrathin Films

Langmuir ◽  
2011 ◽  
Vol 27 (19) ◽  
pp. 11973-11980 ◽  
Author(s):  
Derong Yan ◽  
Haiying Huang ◽  
Tianbai He ◽  
Fajun Zhang
Keyword(s):  
Ultrathin Films ◽  
Microphase Separation

Microphase Separation of Bulk and Ultrathin Films of Polyurethane Elastomers

2008 ◽  
Vol 267 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Mutsuhisa Furukawa ◽  
Ken Kojio ◽  
So Kugumiya ◽  
Yusuke Uchiba ◽  
Yoshitaka Mitsui
Keyword(s):  
Ultrathin Films ◽  
Microphase Separation ◽  
Polyurethane Elastomers

Morphological studies of linear (AB)n multiblock copolymers and their blends

1992 ◽  
Vol 50 (1) ◽  
pp. 384-385
Author(s):  
Richard J. Spontak ◽  
Steven D. Smith ◽  
Arman Ashraf
Keyword(s):  
Electron Microscopy ◽  
Microphase Separation ◽  
Multiblock Copolymers ◽  
First Order ◽  
Morphological Studies ◽  
Transmission Electron ◽  
First Order Phase Transition ◽  
Covalently Bonded ◽  
Total Molecular Weight ◽  
First Order Phase

Block copolymers are composed of sequences of dissimilar chemical moieties covalently bonded together. If the block lengths of each component are sufficiently long and the blocks are thermodynamically incompatible, these materials are capable of undergoing microphase separation, a weak first-order phase transition which results in the formation of an ordered microstructural network. Most efforts designed to elucidate the phase and configurational behavior in these copolymers have focused on the simple AB and ABA designs. Few studies have thus far targeted the perfectly-alternating multiblock (AB)n architecture. In this work, two series of neat (AB)n copolymers have been synthesized from styrene and isoprene monomers at a composition of 50 wt% polystyrene (PS). In Set I, the total molecular weight is held constant while the number of AB block pairs (n) is increased from one to four (which results in shorter blocks). Set II consists of materials in which the block lengths are held constant and n is varied again from one to four (which results in longer chains). Transmission electron microscopy (TEM) has been employed here to investigate the morphologies and phase behavior of these materials and their blends.

Epitaxial growth manner and structure of superconducting oxide films

1990 ◽  
Vol 48 (4) ◽  
pp. 2-3
Author(s):  
Yoshichika Bando ◽  
Takahito Terashima ◽  
Kenji Iijima ◽  
Kazunuki Yamamoto ◽  
Kazuto Hirata ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Film Surface ◽  
High Energy ◽  
Epitaxial Films ◽  
Layer By Layer ◽  
Initial Growth ◽  
In Situ Growth ◽  
High Quality ◽  
Activated Reactive Evaporation

The high quality thin films of high-Tc superconducting oxide are necessary for elucidating the superconducting mechanism and for device application. The recent trend in the preparation of high-Tc films has been toward “in-situ” growth of the superconducting phase at relatively low temperatures. The purpose of “in-situ” growth is to attain surface smoothness suitable for fabricating film devices but also to obtain high quality film. We present the investigation on the initial growth manner of YBCO by in-situ reflective high energy electron diffraction (RHEED) technique and on the structural and superconducting properties of the resulting ultrathin films below 100Å. The epitaxial films have been grown on (100) plane of MgO and SrTiO, heated below 650°C by activated reactive evaporation. The in-situ RHEED observation and the intensity measurement was carried out during deposition of YBCO on the substrate at 650°C. The deposition rate was 0.8Å/s. Fig. 1 shows the RHEED patterns at every stage of deposition of YBCO on MgO(100). All the patterns exhibit the sharp streaks, indicating that the film surface is atomically smooth and the growth manner is layer-by-layer.

scholarly journals Scanning Thermal Microscopy of Ultrathin Films: Numerical Studies Regarding Cantilever Displacement, Thermal Contact Areas, Heat Fluxes, and Heat Distribution

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 491
Author(s):  
Christoph Metzke ◽  
Fabian Kühnel ◽  
Jonas Weber ◽  
Günther Benstetter
Keyword(s):  
Thermal Properties ◽  
Ultrathin Films ◽  
Hexagonal Boron Nitride ◽  
Thermal Contact ◽  
Heat Transfer Process ◽  
Heat Propagation ◽  
Heat Fluxes ◽  
Detailed Knowledge ◽  
Scanning Thermal Microscopy ◽  
Thermal Microscopy

New micro- and nanoscale devices require electrically isolating materials with specific thermal properties. One option to characterize these thermal properties is the atomic force microscopy (AFM)-based scanning thermal microscopy (SThM) technique. It enables qualitative mapping of local thermal conductivities of ultrathin films. To fully understand and correctly interpret the results of practical SThM measurements, it is essential to have detailed knowledge about the heat transfer process between the probe and the sample. However, little can be found in the literature so far. Therefore, this work focuses on theoretical SThM studies of ultrathin films with anisotropic thermal properties such as hexagonal boron nitride (h-BN) and compares the results with a bulk silicon (Si) sample. Energy fluxes from the probe to the sample between 0.6 µW and 126.8 µW are found for different cases with a tip radius of approximately 300 nm. A present thermal interface resistance (TIR) between bulk Si and ultrathin h-BN on top can fully suppress a further heat penetration. The time until heat propagation within the sample is stationary is found to be below 1 µs, which may justify higher tip velocities in practical SThM investigations of up to 20 µms−1. It is also demonstrated that there is almost no influence of convection and radiation, whereas a possible TIR between probe and sample must be considered.

scholarly journals Solvent-exchange process in MOF ultrathin films and its effect on CO2 and methanol adsorption

2021 ◽  
Vol 590 ◽  
pp. 72-81
Author(s):  
M.A. Andrés ◽  
P. Fontaine ◽  
M. Goldmann ◽  
C. Serre ◽  
O. Roubeau ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Exchange Process ◽  
Solvent Exchange ◽  
Methanol Adsorption
Sign in / Sign up

Export Citation Format

Share Document