Surface topology, polymer

In recent years, cyclic polymers (also referred to as polymer rings or macrocycles) became easier to prepare. By a number of different approaches and advances in cyclization techniques, a wide range of novel cyclic polymers have been prepared in good yields [10]. In contrast to linear polymers, cyclic polymers are topologically distinct species, and all monomer units of cyclic polymers are chemically and physically equivalent. This equivalence is due to the fact that their properties are not affected by the nature of the end groups, since cyclic polymers have no chain ends. They include the radius of gyration, intrinsic viscosity, translational friction coefficient, critical solution temperature, refractive index, density, dipole moment, glass transition temperature, and surface property [11]. 

Fortunately, over the past several years, the problems associated with each of the above requirements have been overcome and now integrated opto-chips are now relatively routinely fabricated [2, 3, 5, 63, 64, 271-278, 290-297]. The problem of irregular VLSI surface topology has been overcome by use of planarizing polymers such as Futerrex PC3-6000. The reflow properties of this polymer reduce the 1-6 micron semiconductor circuit features to surface variations of 0.2 microns after planarization. The optical quality of planarized surfac-... 

The effects of simultaneous AO/VUV exposure of the two vinylidene fluoride based polymers were also examined. In both cases significant weight loss and surface erosion resulted from AO attack. Erosion yields were 2.8xl0 24 cm3/atom for PVDF and 2.5x1 O 24 cm3/atom for P(VDF-TrFE), consistent with previous literature data for similar materials. The film orientation of PVDF samples was reflected in the surface topology features after exposure, while the less orientated P(VDF-TrFE) samples had less regular surface patterning after exposure. Significantly, neither AO nor VUV irradiation dramatically altered the piezoelectric properties and we propose that these materials should perform satisfactorily under moderate LEO conditions. 

Figure 4.14. AFM surface topologies of the gratings formed with the formulation of 65 wt% polymer matrix compound in the ratio 20 10 50 20 in TMPTA NVP Mu-TEOS PPG-DTEOS and 35 wt% of E7 in (a) 10 pm and (b) 3 pm scanning lengths.

The strong effect of the surface topology on the epitaxial type of transcrystallization of iPP has been described by Hobbs (81,82). The primary factors affecting transcrystallization on the filler surface include temperature gradient near the filler surface, chemical composition of the filler surface, crystalline morphology of the filler surface, surface energy of the filler, adsorption of nucleants presented in the polymer, epitaxy, and topography of the filler (83-86). 

Surface topology Surface topology dictates cellular infiltration, adhesion, and differentiation. Considering the complex interactions between cells and the extracellular matrix (ECM), hiomimetic TE approaches are becoming increasingly popular. The use of natural polymer and the introduction of specific cell adhesion motifs in synthetic biomaterials have been demonstrated to improve cell adhesion, minimize immune response, and favor tissue-specific cell differentiation. ... 

---