Multilayer morphology

Polymers crystallized from concentrated solutions exhibit more complex crystalline morphology (7). In dilute solutions, polymer coils are isolated from each other, but if the concentration increases, association and entanglement among the chains are favored. Therefore, there is a greater probability that a chain forms part of various crystallites, thus producing aggregated lamellae in multilayer morphologies. 

Core/shell latexes refer to systems with a submicroscopic particle morphology of one polymer forming the center part (the core) and the other polymer covering the core (the shell layer). Core/shell latexes are made via two consecutive emulsion polymerization stages, usually forming a particle structure with the initially polymerized material at the center and the later-formed polymer as the outer layer. If more than two stages are employed in the emulsion polymerization process, latex particles with multilayered morphology can be obtained. 

Nanoparticles exist in spherical, mbe and whisker, and plate-like shapes and at least one of the three dimensions is required to be on a nanometric scale. Nanostructures of layered clays are further categorized as intercalated, in which the polymer chains have penetrated between the clay layers in a well-ordered multilayer morphology, and exfoliated, in which the clay layers have dispersed along the matrix and have no organized slnictme [7]. Carbon nanombes also exhibit two nanostructmes single-walled nanotube and mnltiwalled nanotube, which is composed of several tubes within each other. 

Depending on the nature of the components used (layered silicate, organic cation, and polymer matrix) and the preparation method, three types of hybrid PCNs can be obtained [17]. Phase-separated microcomposites (conventional composites) are obtained when the polymer chains are unable to intercalate within the inorganic sheets clay lamellae remain stacked in structures marked as tactoids as in the pristine mineral. Otherwise, when the polymer chains penetrate in between the clay galleries, an intercalative system is obtained. In this case, the nanocomposite shows, at least in principle, a well-ordered multilayer morphology built up with alternating polymeric and clay layers. When clay platelets are randomly dispersed in the polymer matrix and the lamellae are far apart from each other, so that the periodicity of this platelet arrangement is totally lost, an exfoliated structure is achieved. 

Numerical simulations not only confirm these predictions but also help to obtain the essential characters observed by selection of realistic values of the parameters, these characters being oscillatory formation of the layers, the multilayered morphology and the bifurcation leading to the duplex scale (see Figure 8). 

Tieke B and Weiss K 1984 The morphology of Langmuir-Blodgett multilayers of amphiphilio diaoetylenes—effeots of the preparation oonditions and the role of additives J. Colloid Interface Sol. 101 129-48... 

The first stage in the interpretation of a physisorption isotherm is to identify the isotherm type and hence the nature of the adsorption process(es) monolayer-multilayer adsorption, capillary condensation or micropore filling. If the isotherm exhibits low-pressure hysteresis (i.e. at p/p° < 0 4, with nitrogen at 77 K) the technique should be checked to establish the degree of accuracy and reproducibility of the measurements. In certain cases it is possible to relate the hysteresis loop to the morphology of the adsorbent (e.g. a Type B loop can be associated with slit-shaped pores or platey particles). 

Structure and morphology. Most of the rare-earth elements were encapsulated in multilayered graphitic cages, being in the form of single-domain carbides. The carbides encapsulated were in the phase of RC2 (R stands for rare-earth elements) except for Sc, for which Sc3C4(20] was encapsulated[21]. 

Altered cell morphology Increased growth rate Increased saturation density Formation of multilayers Reduced adhesion to substratum Colony formation in soft agar Reduced serum requirement Altered growth factor requirement Tumor formation in athymic nude mice... 

For PTFE film and PTFE/Si3N4 multilayers, through the observation of the surface morphology after the micro wear test, it is found that there is obvious worn mark and projection in the edge of worn mark when the load is above 70 nN (Figs. 11 and 12). As to the Si3N4 film, there is no worn mark observed even when the maximum load is used in the micro friction test. 

The influence of Pt modihcations on the electrochemical and electrocatalytic properties of Ru(OOOl) electrodes has been investigated on structurally well-defined bimetallic PtRu surfaces. Two types of brmetalhc surfaces were considered Ru(OOOl) electrodes covered by monolayer Pt islands and monolayer PtRu/Ru(0001) surface alloys with a highly dispersed and almost random distribution of the respective surface atoms, with different Pt surface contents for both types of structures. The morphology of these surfaces differs significantly from that of brmetaUic PtRu surfaces prepared by electrochemical deposition of Pt on Ru(0001), where Pt predominantly exists in small multilayer islands. The electrochemical and electrocatal5d ic measurements, base CVs, and CO bulk oxidation under continuous electrolyte flow, led to the following conclusions ... 

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