Finnefrock Adam C, Ulrich Ralph, Toombes Gilman E S, Gruner Sol M, Wiesner Ulrich
Department of Materials Science and Engineering, 329 Bard Hall, Cornell University, Ithaca, New York 14853-1501, USA.
J Am Chem Soc. 2003 Oct 29;125(43):13084-93. doi: 10.1021/ja0355170.
A novel cubic bicontinuous morphology is found in polymer-ceramic nanocomposites and mesoporous aluminosilicates that are derived by an amphiphilic diblock copolymer, poly(isoprene-b-ethylene oxide) (PI-b-PEO), used as a structure-directing agent for an inorganic aluminosilicate. Small-angle X-ray scattering (SAXS) was employed to unambiguously identify the Im(-)3m crystallographic symmetry of the materials by fitting individual Bragg peak positions in the two-dimensional X-ray images. Structure factor calculations, in conjunction with results from transmission electron microscopy, were used to narrow the range of possible structures consistent with the symmetry and showed the plumber's nightmare morphology to be consistent with the data. The samples are made by deposition onto a substrate that imposes a strain field, generating a lattice distortion. This distortion is quantitatively analyzed and shown to have resulted in shrinkage of the crystallites by approximately one-third in a direction perpendicular to the substrate, in both as-made composites and calcined ceramic materials. Finally, the observation of the bicontinuous block-copolymer-derived hybrid morphology is discussed in the context of a pseudo-ternary morphology diagram and compared to existing studies of ternary phase diagrams of amphiphiles in a mixture of two solvents. The calcined mesoporous materials have potential applications in the fields of catalysis, separation technology, and microelectronics.
在由两亲性二嵌段共聚物聚（异戊二烯-b-环氧乙烷）（PI-b-PEO）作为无机硅铝酸盐的结构导向剂衍生得到的聚合物-陶瓷纳米复合材料和介孔硅铝酸盐中发现了一种新型的立方双连续形态。采用小角X射线散射（SAXS）通过拟合二维X射线图像中的各个布拉格峰位置来明确识别材料的Im(-)3m晶体对称性。结合透射电子显微镜的结果进行结构因子计算，以缩小与对称性相符的可能结构范围，并表明管道工噩梦形态与数据一致。样品是通过沉积在施加应变场的基底上制成的，从而产生晶格畸变。对这种畸变进行了定量分析，结果表明，在制成的复合材料和煅烧后的陶瓷材料中，微晶在垂直于基底的方向上均收缩了约三分之一。最后，在伪三元形态图的背景下讨论了双连续嵌段共聚物衍生的混合形态的观察结果，并与两种溶剂混合物中两亲物三元相图的现有研究进行了比较。煅烧后的介孔材料在催化、分离技术和微电子领域具有潜在应用。
