Hexagonally Patterned Lamellar Morphology in ABC Triblock Copolymer/Aluminosilicate Nanocomposites
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- 作者：Gilman E. S. Toombes ; Surbhi Mahajan ; Malcolm Thomas ; Phong Du ; Mark W. Tate ; Sol M. Gruner ; Ulrich Wiesner
- 刊名：Chemistry of Materials
- 出版年：2008
- 出版时间：May 27, 2008
- 年：2008
- 卷：20
- 期：10
- 页码：3278 - 3287
- 全文大小：2095K
- 年卷期：v.20,no.10(May 27, 2008)
- ISSN：1520-5002
文摘
X-ray scattering and electron microscopy were used to characterize the structure of poly(ethylene-alt-propylene-block-ethylene oxide-block-n-hexyl methacrylate) (PEP-b-PEO-b-PHMA) triblock copolymer/aluminosilicate hybrid materials in which the volume fraction of the PEP end-block (0.09 ≤ fPEP ≤ 0.12) was much smaller than that of the PEO-aluminosilicate (0.28 ≤ fPEO+aluminosilicate ≤ 0.44) and PHMA (0.47 ≤ fPHMA ≤ 0.60) domains. These hybrid compounds formed a hexagonally patterned lamellar morphology in which the lamellae were aligned parallel to the material surface (lamellar repeat spacing = 33.0 
3.3 nm, in-plane row spacing = 21.7 1.9 nm). Both the PHMA and PEO-aluminosilicate phases formed continuous, two-dimensional domains permitting individual sheets of the material to be isolated by dispersal in organic solvent. Within each sheet, the lamellar PEO-aluminosilicate domain was hexagonally patterned by an array of “holes” with lower aluminosilicate density. Since the enthalpy of mixing for the small PEP end-block and PEO-aluminosilicate phase is very large, the “holes” in the PEO-aluminosilicate sheet may correspond to micellar PEP domains forming either dimples in the surface of the sheet or pillars spanning the sheet as in the proposed “pillared-lamellae” morphology (Macromolecules 2001, 34, 6994−7008). These results suggest that the use of ABC copolymers as structure-directing agents may provide access to a wide range of morphologies.
3.3 nm, in-plane row spacing = 21.7 1.9 nm). Both the PHMA and PEO-aluminosilicate phases formed continuous, two-dimensional domains permitting individual sheets of the material to be isolated by dispersal in organic solvent. Within each sheet, the lamellar PEO-aluminosilicate domain was hexagonally patterned by an array of “holes” with lower aluminosilicate density. Since the enthalpy of mixing for the small PEP end-block and PEO-aluminosilicate phase is very large, the “holes” in the PEO-aluminosilicate sheet may correspond to micellar PEP domains forming either dimples in the surface of the sheet or pillars spanning the sheet as in the proposed “pillared-lamellae” morphology (Macromolecules 2001, 34, 6994−7008). These results suggest that the use of ABC copolymers as structure-directing agents may provide access to a wide range of morphologies.