Ordered bicontinuous double diamond phase

Several ordered states distinguished by their symmetries have been identified the preferred one depends primarily on the polymer composition [29,38,39]. Some common patterns are lamellar sheets, ordered bicontinuous double diamond (OBDD), hexagonally packed cylindrical arrays, and body-centered-cubic spherical microstructures. If the volume fractions of the two halves of the polymer chain are similar, the interface between the two regions will be flat and the lamellar phase will form. However, if one block is much smaller than the other, then for packing reasons, the interface will curve toward the smaller half (see Fig. 19b), giving, in order of increasing curvature, the OBDD, cylindrical, and spherical microstructure. 

Originally, only the classical set of phases was observed, spheres, cylinders and lamellae. With time and increasing refinement of both theory and experiment other configurations, stable and metastable, were predicted and observed. The ordered bicontinuous double diamond was observed in a star block copolymer (Thomas et al. 1986) and the gyroid in a diblock copolymer (Hajduk et al. 1994). A recent theoretical calculation (Matsen 2012) is shown at left in the figure below, and compared with experimental observations complied from different sources (Matsen 2002) (Figs. 1.12 and 1.13). 

One of the imique features of phase separated block copolymers involves their ordered morphologies which can include spheres, cylinders, lamellae, bicontinuous as well as ordered bicontinuous doubled diamond and gyroid structures (see Figs. 4.17 and 4.18). Gyroid struc-... 

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