Department of Materials Science and Engineering, Cornell University , Ithaca, New York 14850, United States.
Institute for Molecular Engineering, The University of Chicago , Chicago, Illinois 60637, United States.
ACS Nano. 2018 Jan 23;12(1):347-358. doi: 10.1021/acsnano.7b06436. Epub 2017 Dec 19.
Three-dimensional (3D) mesoporous thin films with sub-100 nm periodic lattices are of increasing interest as templates for a number of nanotechnology applications, yet are hard to achieve with conventional top-down fabrication methods. Block copolymer self-assembly derived mesoscale structures provide a toolbox for such 3D template formation. In this work, single (alternating) gyroidal and double gyroidal mesoporous thin-film structures are achieved via solvent vapor annealing assisted co-assembly of poly(isoprene-block-styrene-block-ethylene oxide) (PI-b-PS-b-PEO, ISO) and resorcinol/phenol formaldehyde resols. In particular, the alternating gyroid thin-film morphology is highly desirable for potential template backfilling processes as a result of the large pore volume fraction. In situ grazing-incidence small-angle X-ray scattering during solvent annealing is employed as a tool to elucidate and navigate the pathway complexity of the structure formation processes. The resulting network structures are resistant to high temperatures provided an inert atmosphere. The thin films have tunable hydrophilicity from pyrolysis at different temperatures, while pore sizes can be tailored by varying ISO molar mass. A transfer technique between substrates is demonstrated for alternating gyroidal mesoporous thin films, circumventing the need to re-optimize film formation protocols for different substrates. Increased conductivity after pyrolysis at high temperatures demonstrates that these gyroidal mesoporous resin/carbon thin films have potential as functional 3D templates for a number of nanomaterials applications.
具有亚 100nm 周期晶格的三维（3D）介孔薄膜作为许多纳米技术应用的模板越来越受到关注，但很难通过传统的自上而下的制造方法实现。嵌段共聚物自组装衍生的介观结构为这种 3D 模板形成提供了一个工具包。在这项工作中，通过溶剂蒸气退火辅助聚（异戊二烯嵌段-苯乙烯嵌段-氧化乙烯）（PI-b-PS-b-PEO，ISO）和间苯二酚/苯酚甲醛树脂的共组装，实现了单（交替）各向异性 gyroid 和双 gyroid 介孔薄膜结构。特别是，交替 gyroid 薄膜形态由于大的孔体积分数，非常适合潜在的模板回填过程。在溶剂退火过程中，原位掠入射小角 X 射线散射被用作阐明和导航结构形成过程途径复杂性的工具。所得的网络结构在提供惰性气氛的情况下能够耐受高温。通过在不同温度下进行热解，薄膜具有可调的亲水性，而通过改变 ISO 摩尔质量可以调整孔径。在不同的基底之间演示了交替 gyroid 介孔薄膜的转移技术，避免了为不同的基底重新优化薄膜形成方案的需要。高温热解后的电导率增加表明，这些各向异性 gyroid 介孔树脂/碳薄膜作为许多纳米材料应用的功能性 3D 模板具有潜力。
