Soft materials phases

STM and SFM are free from many of the artifacts that afflict other kinds of profilometers. Optical profilometers can experience complicated phase shifts when materials with different optical properties are encountered. The SFM is sensitive to topography oidy, independent of the optical properties of the surface. (STM may be sensitive to the optical properties of the material inasmuch as optical properties are related to electronic structure.) The tips of traditional stylus profilometers exert forces that can damage the surfaces of soft materials, whereas the force on SFM tips is many orders of magnitude lower. SFM can image even the tracks left by other stylus profilometers. 

These materials exhibit the same type of morphology as the copolyether esters, the polyamide providing the hard segment, and the polyester the soft elastomeric phase. The service temperature is lower than that of the copolyether esters, but apart from this difference they exhibit similar properties. 

An interesting way to prepare shock-resistant coatings [381] follows the synthesis of the ABS-terpolymers, e.g. shock-resistant polystyrene, where a soft, elastomeric phase is incorporated in a hard polymer matrix via covalent bonds. Because organic coatings solidify in situ, elastomeric microgels have been synthesized and mixed to a binder which forms the hard matrix phase before the application of this mixture as a coating material. 

Therefore, at room temperature Fluoro-PSB-II a thermoplastic elastomer with a soft polymer phase (fluorinated block) and a hard phase (PS-block), similar to the parental polystyrene-6-polybutadiene block copolymer. Depending on the relative volume fraction of both components and the continuity of the phases, the resulting bulk material is rubbery or a high-impact solid. 

The relatively low erosion resistance of the two SiSiC materials in comparison to silicon nitride and sialon ceramics is due in part to the lateral chipping of the large SiC grains and in part to the relatively low erosion resistance of the soft Si phase. 

However, PDMS-modified silica aggregates seem to coat nearly the entire toner particle. Their topographical diameter is doubled compared to the HMDS-coated particles, but the diameter estimated from the phase image is very similar to the one foimd for the HMDS-modified ones. The maximum phase shift is reduced compared to the samples above. This indicates that the silica aggregates are covered by a soft material - the silylation layer. This soft material covers not only the particles but also the resin surface in between them. This can be seen by the decreased phase shift in between the silica particles compared to the pure resin. As in sample (Fig. 5b), probably the PDMS silylation layer interacts with the toner resin surface, increasing the overall adhesion. 

Taking into account that the Tg of the soft-segment amorphous phase lies between -50 and 0 °C, depending on the PCc content (Table 5.3), one can expect that at room temperature such a phase will be a very soft material much closer to a liquid than to a solid. For this reason one may expect that 0 and, as a result, that H will be depressed with increasing values of w according to the simple expression ... 

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