High-flux Gas-separation Membranes Based on Ultrathin Hyperbranched Polymer Films Grafted onto Highly Porous Supports

膜分离因其简单、低能源成本和在偏远地区操作的能力而具有吸引力。然而，要充分利用膜技术的优势，将需要具有更高渗透性和选择性的新膜。不幸的是，通过膜的通量通常与选择性成反比。超薄膜的发展将允许高通量，但这种结构的合成具有足够的选择性，强度和质量是一个持续的挑战。该方案解决了开发和理解选择性和超薄（50 nm）气体分离膜的挑战，通过使用接枝到多孔支架上的超支化聚丙烯酸（PAA）薄膜。PAA薄膜将提供超薄和选择性层，而高渗透性衬底是机械稳定性所必需的。混合PAA薄膜将是一种独特的膜材料，因为它们的分支结构允许完全覆盖基底孔，它们的层层合成将产生厚度从3-100纳米不等的薄膜，并且薄膜中高密度的羧酸基团将允许在膜形成后进行广泛的化学修饰

Membrane-based separations are attractive because of their simplicity, low energy costs, and ability to operate in remote locations. Full utilization of the advantages of membrane technology, however, will require new membranes with increased permeabilities and selectivities. Unfortunately, flux through membranes is generally inversely related to selectivity. The development of ultrathin membranes will allow high flux, but synthesis of such structures with sufficient selectivity, strength, and quality is an ongoing challenge. This proposal addresses the challenge of developing and understanding selective and ultrathin ( 50 nm) gas-separation membranes through the use of hyperbranched poly acrylic acid (PAA) films grafted onto porous supports. PAA films will provide an ultrathin and selective layer while the highly permeable substrate is required for mechanical stability. Hyberbranced PAA films will be unique membrane materials because their branched structure will allow full coverage of substrate pores, their layer-by-layer synthesis will yield films whose thickness can be varied from 3-100 nm, and the high density of carboxylic acid groups in the film will permit a wide range of chemical modifications even after membrane formation