Core-Shell Double-Gyroid

Fig. 18 Phase space of PI-fc-PS-fc-PEO in vicinity of ODT. Filled and open circles-. ordered and disordered states, respectively, within experimental temperature range 100 < T/° C< 225. Outlined areas compositions with two- and three-domain lamellae (identified by sketches) shaded regions three network phases, core-shell double gyroid (Q230), orthorhombic (O70), and alternating gyroid (Q214). Overlap of latter two phase boundaries indicates high- and low-temperature occurrence, respectively, of each phase. Dashed line condition tfin = 0peo associated with symmetric PI-fc-PS-fc-PEO molecules. From [75]. Copyright 2004 American Chemical Society...

Fig.20 Top row single unit-cell models of core-shell double gyroid (Q °), orthorhombic (O °), and alternating gyroid (Q ) cross-sectioned to reveal interfacial configuration. Bottom row. direct projections of cross-sectioned interfaces. Sketches of PI-fi-PS-fi-PEO chains show how each morphology is assembled. Projections appear to scale that is, the core-shell double gyroid unit cell is roughly twice the thickness of the other two. From [75]. Copyright 2004 American Chemical Society...

The core-shell IMDS was first discovered in ABC triblock copolymers where two chemically identical interpenetrating double-gyroid networks are comprised of cores of C encased in shells of B and embedded in a matrix of A [6, 7, 35, 36]. Thus, the core-shell double-gyroid IMDS in these triblock copolymers is pentacontinuous. One could envision, that a copolymer with four or more chemically distinct blocks could also form a version of the core-shell gyroid with more than one sheU. 

SEM images of a nanotubular nickel oxide DG obtained after thermal annealing based on the KirkendaU effect is shown in Fig. 6.6. The extent of void formation driven by the KirkendaU effect can be controlled by the elective dissolution of the template before thermal annealing. Thermal annealing performed on template-freed samples led to an unhindered expansion of the Ni struts which is based on the NKE with pronounced nanotube formation (Fig. 6.6b). In contrast, the expansion of the oxidizing Ni struts as well as the extent of nanotube void formation is constrained (Fig. 6.6c). The following discussion focuses on nanotubular NiO with pronounced void formation. The nanotubular array can be considered as a core-shell double-gyroid which was discussed in Sect. 2.6. 

With increasing amoimt of triblock copolymer, blends of lamellar SBT triblock copolymers with the asymmetric SB diblock copolymer form core-shell spheres, core-shell cylinders, core-shell double gyroids, and lamellae (Fig. 34). T forms the core domains in these morphologies, which can be considered as coreshell analogues of the well-known diblock copolymer morphologies (76). 

Hiickstadt, H., Goldacker, T, Gdpfert, A., and Abetz, V. (20(X)a) Core-shell double gyroid morphologies in ABC triblock copolymers with different chain topologies. Macromolecules, 33,3757-3761. 

While the blend BiSi,iVi,6 forms a core-shell double gyroid morphology, the rather similar (in terms of net composition) system IiSiVi presented in Section 7.02.2.1.2 shows a dode-cagonal morphology. The pure 3-miktoarm star terpolymers... 

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