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CN-122006527-A - Polydimethylsiloxane membrane based on fluorocarbon molecular brush regulation and control and preparation method thereof

CN122006527ACN 122006527 ACN122006527 ACN 122006527ACN-122006527-A

Abstract

The invention belongs to the technical field of membrane separation, and particularly relates to a polydimethylsiloxane membrane based on fluorocarbon molecular brush regulation and control and a preparation method thereof, which comprise a porous supporting layer and a separating layer formed on the supporting layer, wherein the separating layer is formed by modified polydimethylsiloxane, the modified polydimethylsiloxane is obtained by copolymerizing vinyl-terminated polydimethylsiloxane and perfluorovinyl monomers, the structural general formula of the perfluorovinyl monomers is CF 3 (CF 2 )n-CH=CH 2 , the perfluorovinyl monomers are introduced as molecular brushes, the free volume distribution of a PDMS membrane is precisely controlled, the remarkable improvement of gas permeation selectivity is realized, the breakthrough improvement is mainly caused by the high hydrophobic and oleophobicity, low surface energy and rigid structure of a perfluoro chain segment, the characteristics effectively enlarge the distance between PDMS chain segments, and meanwhile, the strong electronegativity of fluorine atoms can enhance adsorption selectivity through the interaction with quadrupole moments of gas molecules, so that more continuous gas specific transmission channels are formed.

Inventors

  • ZHU CHUHONG
  • WU HONGYU
  • YANG XU
  • ZHOU XIAO
  • TAN JU

Assignees

  • 中国人民解放军陆军军医大学

Dates

Publication Date
20260512
Application Date
20251225

Claims (8)

  1. 1. A polydimethylsiloxane membrane regulated and controlled based on fluorocarbon molecular brushes, characterized by comprising a porous supporting layer (1) and a separating layer (2) formed on the supporting layer; The separation layer is formed by modified polydimethylsiloxane, the modified polydimethylsiloxane is obtained by copolymerizing vinyl-terminated polydimethylsiloxane and a perfluorinated vinyl monomer, wherein the structural general formula of the perfluorinated vinyl monomer is CF 3 (CF 2 )n-CH=CH 2 , and n is an integer of 3-11.
  2. 2. A fluorocarbon molecular brush-based polydimethylsiloxane membrane as defined in claim 1, wherein said perfluorovinyl monomer is preferably selected from one or more of 1H, 2H-perfluoro-1-hexene, (perfluorohexyl) ethylene, 1H, 2H-perfluoro-1-decene, 1H, 2H-perfluoro-1-dodecene, 1H, 2H-perfluoro tetradecyl-1-ene, and the like.
  3. 3. A fluorocarbon molecular brush-based controlled polydimethylsiloxane membrane as set forth in claim 1, characterized in that said perfluorovinyl monomer is incorporated in an amount of 0.5% to 60%, preferably 5% to 50% by mass of the vinyl-terminated polydimethylsiloxane.
  4. 4. The polydimethylsiloxane membrane regulated and controlled based on the fluorocarbon molecular brush according to claim 1, wherein the porous supporting layer (1) is a polysulfone hollow fiber membrane or a flat plate membrane.
  5. 5. The polydimethylsiloxane membrane regulated and controlled based on fluorocarbon molecular brush as set forth in claim 1, wherein the separation layer (2) uses medical grade vinyl-terminated polydimethylsiloxane as a monomer, a platinum-series catalyst is used, and the free volume distribution of the polydimethylsiloxane membrane is precisely controlled by introducing perfluorovinyl monomers as molecular brushes.
  6. 6. A method of preparing a fluorocarbon-based molecular brush-mediated polydimethylsiloxane membrane as recited in any one of claims 1-5, comprising the steps of: s1, preparing a casting solution, namely dissolving vinyl-terminated polydimethylsiloxane, a platinum catalyst and a perfluorinated vinyl monomer in a single or mixed organic solvent (such as n-hexane, n-heptane and toluene) according to a proportion to form a uniform casting solution S2, coating or dip-coating the casting film liquid on the surface of the polysulfone supporting layer, and forming a uniform thin layer by controlling the thickness of the knife coating or dip-coating S3, thermal crosslinking and curing, namely, carrying out hydrosilylation reaction on the vinyl-terminated polydimethylsiloxane membrane and the perfluorinated vinyl monomer under the catalysis of a platinum catalyst to form a crosslinked network structure. In the process, the perfluoro chain segment is connected into a polydimethylsiloxane membrane network in a chemical bonding mode to form a molecular brush structure S4, post-treatment, namely cleaning and drying the cured film material to obtain a final product.
  7. 7. The method for preparing a polydimethylsiloxane membrane based on fluorocarbon molecular brush control as recited in claim 6, wherein the organic solvent is one or more of n-hexane, n-heptane or toluene.
  8. 8. The method for preparing the polydimethylsiloxane membrane based on fluorocarbon molecular brush regulation and control as set forth in claim 6, wherein the thermal crosslinking and curing temperature is 50-120 ℃ and the time is 0.3-4 hours.

Description

Polydimethylsiloxane membrane based on fluorocarbon molecular brush regulation and control and preparation method thereof Technical Field The invention belongs to the technical field of membrane separation, and particularly relates to a polydimethylsiloxane membrane based on fluorocarbon molecular brush regulation and control and a preparation method thereof. Background Polydimethylsiloxane (PDMS), a typical representative of an organosilicon material, has been receiving a great deal of attention in the field of gas separation membranes because its backbone is composed of Si-O-Si bonds, with excellent flexibility, good biocompatibility, and high gas permeability. The helical molecular chain structure of PDMS gives it a large free volume, providing a fast transport channel for gas molecules. However, the conventional PDMS membrane has several significant drawbacks in the field of gas separation, limiting its application in high performance gas separation scenarios. First, the free volume elements of conventional PDMS films are unevenly distributed, uncontrollable in size, and there is a significant tradeoff between gas permeability and selectivity (trade-off effect). Although PDMS has a high permeability for most gases, its gas separation selectivity is generally insufficient, especially in the O 2/N2 system and medical applications where accurate separation is required. In addition, the existing PDMS film mostly adopts an organotin compound (such as dibutyl tin dilaurate) as a catalyst, which has obvious risks of neurotoxicity, reproductive toxicity and the like, and the ECMO oxygenation film directly contacts blood, so that the requirement on biocompatibility is extremely high. For example, in vitro membrane pulmonary oxygenation (ECMO) applications, the biocompatibility, blood oxygenation efficiency, and carbon dioxide removal capacity of conventional PDMS membranes are difficult to meet for clinical high-efficiency rescue. In particular, in recent years, researchers have attempted to improve the properties of PDMS films by various physical or chemical methods. For example, some techniques use nanoparticle doping (e.g., carbon nanotubes, silica, etc.) to enhance the separation performance of PDMS films, but such methods often suffer from non-uniform nanoparticle dispersion, easy agglomeration, interface defects, and the like. Other methods adjust the free volume by controlling the chemical crosslinking degree, but the change of the crosslinking degree often affects the mechanical strength and the permeability of the membrane at the same time, so that the ideal balance is difficult to obtain. Disclosure of Invention The invention aims to provide a polydimethylsiloxane membrane based on fluorocarbon molecular brush regulation and control and a preparation method thereof, aiming at solving the problem that in recent years, researchers try to improve the performance of a PDMS membrane through various physical or chemical methods. For example, some techniques use nanoparticle doping (e.g., carbon nanotubes, silica, etc.) to enhance the separation performance of PDMS films, but such methods often suffer from non-uniform nanoparticle dispersion, easy agglomeration, interface defects, and the like. Other methods adjust the free volume by controlling the chemical crosslinking degree, but the change of the crosslinking degree often affects the mechanical strength and the permeability of the membrane at the same time, so that the ideal balance is difficult to obtain. In order to achieve the aim, the invention provides the technical scheme that the polydimethylsiloxane membrane based on fluorocarbon molecular brush regulation and control and the preparation method thereof comprise a porous supporting layer and a separating layer formed on the supporting layer; The separation layer is formed by modified polydimethylsiloxane, the modified polydimethylsiloxane is obtained by copolymerizing vinyl-terminated polydimethylsiloxane and a perfluorinated vinyl monomer, wherein the structural general formula of the perfluorinated vinyl monomer is CF 3(CF2)n-CH=CH2, and n is an integer of 3-11. As the polydimethylsiloxane membrane regulated and controlled by the fluorocarbon molecular brush and the preparation method thereof, the perfluorovinyl monomer is preferably selected from one or more of 1H, 2H-perfluoro-1-hexene, (perfluorohexyl) ethylene, 1H, 2H-perfluoro-1-decene, 1H, 2H-perfluoro-1-dodecene, 1H, 2H-perfluoro-tetradecyl-1-ene and the like. As the polydimethylsiloxane membrane regulated and controlled based on the fluorocarbon molecular brush and the preparation method thereof, the introduction amount of the perfluorovinyl monomer is preferably 0.5-60% of the mass of vinyl-terminated polydimethylsiloxane, and is preferably 5-50%. As the polydimethylsiloxane membrane based on fluorocarbon molecular brush regulation and control and the preparation method thereof, the porous supporting layer is preferably a polysulfone hol