Bicontinuous morphological structure

The mechanism of formation of morphology structures in iPP-E-plastomers blends via shear-dependent mixing and demixing was investigated by optical microscopy and electron microscopy. A single-phase stmcture is formed under high shear condition in injection machine after injection, namely under zero-shear environments, spinodal decomposition proceeds and leads to the formation of a bicontinuous phase stmcture. The velocity of spinodal decomposition and the phase separation depend on the molecular stmcture of iPP and E-plastomer components. 

In the range where bicontinuous morphologies are obtained, KIc may attain a maximum local value (but it then increases again for phase-inverted structures). The presence of this maximum seems to be related to the formation of an incipient phase-inverted structure that exhibits a lack of adhesion between both phases. In these cases, bicontinuous or double-phase morphologies lead to a better fracture resistance (Girard-Reydet et al., 1997). 

Phase morphologies of immiscible binary homopolymer blends evolve from circular domains of one phase dispersed in the matrix of another through a bicontinuous domain structure to the inverse case of the former [106], When a blend is deposited in thin films, its morphology is also affected by interactions of the polymers constituting the blend with the film interfaces. 

D visualization of bicontinuous morphologies in block copolymer systems has been achieved [26-27] by TEMT (see Sect 2.2). This technique affords the real-space structural analysis of complex nanoscale morphologies without a priori synunetry or surface assumptions [97]. Application of numerical methods developed [39, 98] to measure interfacial curvatures from 3D LSCM images of SD polymer blends (see Sects. 3.2.3 and 4.3.3) to a TEMT reconstruction of the G morphology yields the first experimental measurements of interfacial curvature distributions, as well as (H) and an, in a complex block copolymer nanostructure. 

So far, we have shown that both the polymer mixture and block copolymer exhibit bicontinuous morphologies. The bicontinuous structure of the polymer mixture is a transient one of the order of microns, while that of the block copolymer is a nanometer-scale (equilibrium) structure. An introduction of the chemical covalent bond in order to connect dissimilar constituent sequences to form block copolymer makes such differences. At the same time, however, although these two morphologies are far different in size, they appear grossly similar. In the present section, let us compare the two polymeric morphologies in terms of the geometry to find out a possible effect of the chemical junction in polymer chains. 

It is well known that block copolymers and graft copolymers composed of incompatible sequences form the self-assemblies (the microphase separations). These morphologies of the microphase separation are governed by Molau s law [1] in the solid state. Nowadays, not only the three basic morphologies but also novel morphologies, such as ordered bicontinuous double diamond structure, are reported [2-6]. The applications of the microphase separation are also investigated [7-12]. As one of the applications of the microphase separation of AB diblock copolymers, it is possible to synthesize coreshell type polymer microspheres upon crosslinking the spherical microdomains [13-16]. 

In what follows we will discuss systems with internal surfaces, ordered surfaces, topological transformations, and dynamical scaling. In Section II we shall show specific examples of mesoscopic systems with special attention devoted to the surfaces in the system—that is, periodic surfaces in surfactant systems, periodic surfaces in diblock copolymers, bicontinuous disordered interfaces in spinodally decomposing blends, ordered charge density wave patterns in electron liquids, and dissipative structures in reaction-diffusion systems. In Section III we will present the detailed theory of morphological measures the Euler characteristic, the Gaussian and mean curvatures, and so on. In fact, Sections II and III can be read independently because Section II shows specific models while Section III is devoted to the numerical and analytical computations of the surface characteristics. In a sense, Section III is robust that is, the methods presented in Section III apply to a variety of systems, not only the systems shown as examples in Section II. Brief conclusions are presented in Section IV. 

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