Polymers of Intrinsic Microporosity (PIMs) Gas Separation Membranes: A mini Review

Abstract

Polymers of Intrinsic Microporosity (PIMs) are broadly recognized as a potential next generation membrane material for gas separations due to their ultra-permeable characteristics. This mini review aims to provide an overview of these materials and capture its very essence, from chemistry to applications. PIMs-based gas separation membranes are divided into three main categories, i.e., neat PIMs, polymer blend PIMs, and mixed matrix PIMs membranes. This review covers a wide spectrum of PIMs with their gas diffusion mechanisms and separation performance, all of which are examined in detail. Core challenges and opportunities of PIMs membrane technology are reviewed, and this article concludes with future perspectives on PIMs. This mini review establishes a comprehensive understanding of the key technological competence and barriers of PIMs for next-generation gas separations membranes. S ignificant advances in the science and engineering of membrane materials and separation processes have been witnessed in recent decades. Membranes have demonstrated the capability of reducing the enormous amount of energy consumption for gas separations, compared to conventional thermally driven separation processes, like cryogenic distillation [1]. Indeed, membrane separation process is cost-effective and environmentally friendly with small physical footprints. Interests of membrane technology have been growing increasingly in past decades. Key areas that membranes are at play include CO 2 capture, nitrogen generation, hydrogen/helium recovery, natural gas sequestration and biogas purification [2]. Regarded as a new family of membrane materials, Polymers of Intrinsic microporosity (PIMs) have exhibited extremely high gas separation productivity and drawn extensive attention world-widely. The intrinsic microporosity leverages PIMs membranes to far exceed the Robeson upper bound limit of polymeric membranes, which opens an entirely new avenue for gas separations [3]. This review addresses the key developments and advances of PIMs as a super-permeable membrane material for gas separations. Specifically, this paper presents a comprehensive overview of three imperative types of PIMs membranes: those made from, respectively, neat PIMs, polymer blend PIMs, and mixed matrix PIMs.

Correlating Gas Permeability and Young’s Modulus during the Physical Aging of Polymers of Intrinsic Microporosity Using Atomic Force Microscopy

“…9 PIMs demonstrate attractive properties for membranes with a combination of very high permeability, good separation factor, good mechanical properties and capability to be solution-processed. 10 Very recently, rigid amidoxime-modified PIMs achieved highly permeable, selective and plasticization-resistant membranes for natural gas sweetening. 11 Like all glassy polymers with high fractional free volume, PIMs suffer from physical aging as a consequence of the non-equilibrium nature of the glassy state, leading to a slow relaxation and rearrangement of the molecular structure.…”

Highly Permeable Matrimid®/PIM-EA(H2)-TB Blend Membrane for Gas Separation

“…With their unique properties, starting with PIM-1 [19] that defined the 2008 Robeson upper bound [2], numerous new PIMs with a wide range of different chemical structures [6,20,21,22,23,24,25,26,27,28] and increasingly efficient gas separation performance, have moved the Robeson upper bounds further for several gas pairs [3]. Despite their high permeability, the sophisticated synthesis and high costs hinder PIMs from being the basis for large scale membrane production and industrial applications at present [29]. In addition, for demanding separations, their modest selectivity needs improvement.…”

Membranes with Intrinsic Micro-Porosity: Structure, Solubility, and Applications

“…The microporous polymer membranes (including PIMs) have exhibited extremely high separation performance in gas separation, and have been leveraged in polymer membranes to surpass the Robeson upper bounds, which open an entirely new methodology for gas separation [21,26]. Many reviews on gas separation using microporous polymer membranes have, thus, been published [4,5,16,21,91,92,93]. Besides excellent separation performance in gas separation, microporous polymer membranes can also exhibit good separation performance in other separations such as nanofiltration, pervaporation, and gas/vapor separation.…”

“…This successful commercialization nonetheless renewed the hope for the future industrialization of PIMs or microporous polymer membrane. Many papers have been published on optimal PIMs membranes, the development of PIMs membranes with new structures, new applications, and so on [3,5,21]. To date, more than 400 papers have been published on the synthesis, modification, physical properties, and applications.…”