Smooth polymer surfaces, morphology

Naoi and co-workers [55], with a QCM, studied lithium deposition and dissolution processes in the presence of polymer surfactants in an attempt to obtain the uniform current distribution at the electrode surface and hence smooth surface morphology of the deposited lithium. The polymer surfactants they used were polyethyleneglycol dimethyl ether (molecular weight 446), or a copolymer of dimethylsilicone (ca. 25 wt%) and propylene oxide (ca. 75 wt%) (molecular weight 3000) in LiC104-EC/DMC (3 2, v/v). 

Fig. 4 and Fig. 5 show the surface morphologies aftm photo-ablation of PMMA/pyrene, and CMS, CMS/pyrene respectively. In these figures a copper-mesh mask was used in contact with the polymer films for the gena-atkm of sharp etch patterns. For PMMA/pyrene films, in the low pyrene concentration range, the etched surface is quite rough with dendritic and needle-like structures as well as solidified droplets on the bottom of the irradiated areas present although the edges of the etched features are reasonably sharp (Fig. 4a). When the laser fiuence is increased, the etched surface becomes cleaner and more smooth. At a high pyrene concentration, clean and sharp etch patterns can be obtained at a relatively low fiuence, e.g., at a = 1.04 x 10 cm and F = 0.3 J/cm as shown in Fig. 4b. In most cases, periodic structures are observed near the edges of the wire mask, which most likely result from the optical diffraction effect of the wires.

A scanning electron micrograph of the formed polymer, Figure 8.15, reveals a relatively smooth, caramel-like looking surface, containing many craters. A closer look inside the crater reveals a comparatively even compact microspheroid surface morphology. 

Pure polymers lack the degree of hardness required in the wall and therefore tend to collapse after the removal of the core. Accordingly, the presence of ceramic precursor in the polymer solution was essential not only to stabilize the compound jet and entrain the oil uniformly but also to form rigid walls necessary for maintenance of the tubular shape. It was also suggested that the sheath should be able to withstand the capillary forces during core extraction in order to maintain the hollow fiber morphology. Further, the use of immiscible solutions was necessary to form continuous hollow libers with a smooth interior surface. When a miscible solution was... 

These qualitative deductions, which are based on considering a smooth surface, lead to a contradiction as the polymer surface-treated before metalization appears to be oxidized over an appreciable depth whilst the oxidized polymer layer left on the metal side after the rupture does not screen completely aluminum. Actually an AFM examination has shown that the surfaces obtained after rupture are not smooth. They present a nodular morphology with a rms roughness (measured on 2 x 2 pm ) in the range of 3-7 nm, i.e., of the order of the IMFP. Further analysis of the results would require modeling, nsing the kind of approach described below. 

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