Synthesis of Two-Dimensional Polymers as Ultrathin Membranes for Molecular Sieving

用于分子筛分的二维聚合物超薄膜的合成

• 批准号: 448624984
• 负责人: Professor Dr. Armin Gölzhäuser
• 金额: --
• 依托单位: National Natural Science Foundation of China
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/448624984?language=en
• 关键词: Synthesis; Two; Dimensional; Polymers; Ultrathin

Micro- and nanoporous materials act as selective barriers and play important roles as energy efficient gas and liquid separation membranes in industrial processes as well for environmental technologies, such as CO2 capture or water treatment. One of the goals in developing new membrane materials is to achieve a high flux as well as a high selectivity, while maintaining a high mechanical stability. Since the flux through a membrane is inversely proportional to the thickness of the selective layer, robust two-dimensional (2D) sheets with thicknesses of one to a few atoms or molecules would be excellent materials for ultrathin high-performance membranes. However, most 2D sheets do not have pores with well-defined dimensions at the molecular scale and it is thus a great challenge to develop homoporous membranes (films with homogenous pores open at both ends) with pore diameters below 3 nm and a thickness of less than 50 nm. In the proposed project, a class of such membranes with pore sizes between 0.25 nm and 2.6 nm will be fabricated from freestanding 2D polymers. It will be explored how stable and flexible they are and if molecules and atoms can be translocated through them. The project aims to establish versatile and reliable interfacial synthesis methodologies (gas-water, surfactant-water and liquid-liquid interfaces) towards highly crystalline 2D polymers with well-defined pores (size, shape, pore-density and functional group at the periphery of the pores), which can be rationally designed on demand at the molecular level. The project will produce macroscopic-sized 2D polymer crystals with a thicknesses from single layer to multilayers. Both in-situ (grazing-incidence wide-angle X-ray scattering) and ex-situ (STM, TEM) techniques will elucidate the structure of the precursors, model monomers, reaction intermediates at the interface, model compounds and 2D polymer crystals. Based on the experimental results together with simulation, correlations between structures of raw materials and final products will be analyzed to deduce the reaction mechanism for the formation of 2D polymers. Furthermore, critical effects of monomer structures, polymerization degrees, domain sizes, grain boundaries, edge structures, pore structures and thickness on the permeance and selectivity of the 2D polymer crystals will be addressed. Key functions for the operation of this intriguing class of 2D polymer crystals as molecular sieves for separation will be explored. As the key achievements, the applicants expect reliable interfacial synthesis methodologies, delineation of structure-property relationships and superior separation performance of the 2D polymer membranes. In the proposed project, the groups of the PIs join forces and combine their proven expertise in 2D materials, polymer chemistry, nanostructure fabrication and membrane science to explore how freestanding homoporous 2D polymers can be created and what their structure-property correlations are.

微孔和纳米孔材料作为选择性屏障，在工业过程中作为高效的气体和液体分离膜以及环境技术，如二氧化碳捕集或水处理，发挥着重要的作用。开发新型膜材料的目标之一是在保持高机械稳定性的同时实现高通量和高选择性。由于通过膜的通量与选择层的厚度成反比，因此厚度为一个到几个原子或分子的坚固的二维(2D)膜将是制作超薄高性能膜的极佳材料。然而，大多数2D片材在分子尺度上没有定义好尺寸的孔，因此开发孔径小于3 nm、厚度小于50 nm的均孔膜(两端均质孔开口的膜)是一个巨大的挑战。在拟议的项目中，将由独立的2D聚合物制备一类孔径在0.25 nm到2.6 nm之间的此类膜。它将探索它们的稳定性和灵活性，以及分子和原子是否可以通过它们进行转移。该项目旨在建立通用和可靠的界面合成方法(气-水、表面活性剂-水和液-液界面)，以获得具有明确孔(大小、形状、孔密度和孔外围的官能团)的高结晶2D聚合物，这些孔可以根据需要在分子水平上进行合理设计。该项目将生产宏观尺寸的2D聚合物晶体，厚度从单层到多层。原位(掠入射广角X射线散射)和非原位(STM，TEM)技术将阐明前驱体、模型单体、界面反应中间体、模型化合物和二维聚合物晶体的结构。在实验结果的基础上，结合模拟，分析原料和最终产物的结构之间的相关性，以推断形成2D聚合物的反应机理。此外，还将讨论单体结构、聚合度、微区尺寸、晶界、边缘结构、孔结构和厚度对二维聚合物晶体的渗透性和选择性的关键影响。这类耐人寻味的2D聚合物晶体作为分子筛用于分离的操作的关键功能将被探索。作为关键成果，申请人期待可靠的界面合成方法、结构-性能关系的描述以及2D聚合物膜优异的分离性能。在拟议的项目中，PI小组联合起来，结合他们在2D材料、聚合物化学、纳米结构制造和膜科学方面的成熟专业知识，探索如何创建独立的同孔2D聚合物，以及它们的结构-性能相关性。