Microphase separation structural morphology

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]. 

As aforementioned, diblock copolymer films have a wide variety of nanosized microphase separation structures such as spheres, cylinders, and lamellae. As described in the above subsection, photofunctional chromophores were able to be doped site-selectively into the nanoscale microdomain structures of the diblock copolymer films, resulting in nanoscale surface morphological change of the doped films. The further modification of the nanostructures is useful for obtaining new functional materials. Hence, in order to create further surface morphological change of the nanoscale microdomain structures, dopant-induced laser ablation is applied to the site-selectively doped diblock polymer films. 

Predicting the characteristic sizes and morphologies of these nanostructures has been an intense topic of investigation from both the theoretical and experimental points of view. Critical parameters are the degree of polymerization and the volume fraction of the constituent blocks, as well as the Flory-Huggins parameter between them. More complete information about microphase separated structures in bulk block copolymers can be found in the book of Hamley [2],... 

UsingTEM to identify blend morphology, two diblocks with/ps 0.8 that form cubic-packed spherical phases and cylindrical phases respectively in the pure copolymer were found not to macrophase separate in a blend with d = 2.2, but to form single domain structures (cylinders or spheres) in the blend (Koizumi et al. 1994c). Similarly, blending a diblock with fK = 0.26 with one with fK = 0.64 (d = 1.2) led to uniform microphase-separated structures, with a lamellar phase induced in the 50 50 blend. Vilesov et al. (1994) also observed that blending two PS-PB diblocks with approximately inverse compositions (i.e. 22wt% PS and 72 wt% PS) induces a lamellar phase in the 50 50 blend. These examples all correspond to case (i). 

Figure 18c displays swelling kinetics of two SV films with the same initial thickness but different microphase-separated structures. The curves show up to 10% larger swelling (smaller poi) of SV films with the initial bulk lamella morphology as compared to the films with the non-bulk micelle phase [119],... 

We note that earlier research focused on the similarities of defect interaction and their motion in block copolymers and thermotropic nematics or smectics [181, 182], Thermotropic liquid crystals, however, are one-component homogeneous systems and are characterized by a non-conserved orientational order parameter. In contrast, in block copolymers the local concentration difference between two components is essentially conserved. In this respect, the microphase-separated structures in block copolymers are anticipated to have close similarities to lyotropic systems, which are composed of a polar medium (water) and a non-polar medium (surfactant structure). The phases of the lyotropic systems (such as lamella, cylinder, or micellar phases) are determined by the surfactant concentration. Similarly to lyotropic phases, the morphology in block copolymers is ascertained by the volume fraction of the components and their interaction. Therefore, in lyotropic systems and in block copolymers, the dynamics and annihilation of structural defects require a change in the local concentration difference between components as well as a change in the orientational order. Consequently, if single defect transformations could be monitored in real time and space, block copolymers could be considered as suitable model systems for studying transport mechanisms and phase transitions in 2D fluid materials such as membranes [183], lyotropic liquid crystals [184], and microemulsions [185],... 

In scientific terms, the unusual ion-clustered morphology of the perfluorinated ionomer polymers has provoked much interest. Clearly, the microphase-separated structure that is revealed through various types of experiments is strongly related to their unusual transport properties. It is important to refine our understanding of this relationship in order to exploit these materials in various electrochemical applications. 

Physical characterization of macromolecular systems strives to determine chemical structure/property relationships. This subfield includes study of thermomechanical performance viscoelastic properties surface properties, adhesion science thermal transitions morphological analysis, including semicrystalline, amorphous, liquid-crystalline, and microphase-separated structures. Structural analysis employs electron microscopy, con-focal microscopy, optical microscopy, x-ray photoelectron spectroscopy, atomic force microscopy, and x-ray and neutron scattering of macromolecular compositions. 

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