Surface modification method for polytetrafluoroethylene separation membrane

A polytetrafluoroethylene, surface modification technology, applied in the direction of semi-permeable membrane separation, chemical instruments and methods, membrane technology, etc., can solve the problems of poor hydrophilicity of PTFE separation membrane, complex modification process, etc., to achieve pore size and surface properties Continuous, easy mass production, and the effect of improving anti-pollution ability

Active Publication Date: 2012-11-14
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to change the growth mechanism of the atomic layer deposition layer on the surface of the PTFE separation membrane, so that the deposition layer is uniform and smooth, and change the problems of poor hydrophilicity, small flux, easy pollution and complex modification process of the PTFE separation membrane, and Provides a simple and efficient method for surface modification of polytetrafluoroethylene separation membranes

Method used

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  • Surface modification method for polytetrafluoroethylene separation membrane
  • Surface modification method for polytetrafluoroethylene separation membrane
  • Surface modification method for polytetrafluoroethylene separation membrane

Examples

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Embodiment 1

[0025] Example 1: First, put the PTFE separation membrane into the plasma chamber, vacuumize, adjust the plasma power to 22W, and treat the front and back sides for 5 minutes. Titanium isopropoxide (TIP) was used as the first precursor, deionized water (H 2 O) is the second precursor, high-purity nitrogen (N 2 ) as carrier and sweep gas. The pulse time of the two precursors was 0.2s and 0.015s respectively, the exposure time of the precursor was 5s, and the cleaning time was 20s. Heat the temperature of the reaction chamber to 150°C, keep the membrane at the set temperature of the reaction chamber for 2 minutes, and prepare modified membranes with 20, 50, 100, 150, 200, 250, and 300 cycles respectively.

[0026] Table 1 shows the composition of surface elements before and after plasma treatment of PTFE membrane. (measured by XPS)

[0027]

[0028] It can be seen from Table 1 that after the plasma treatment of the PTFE membrane, 1.06 (at.%) of oxygen and 0.31 (at.%) of n...

Embodiment 2

[0033] Example 2: First, put the PTFE separation membrane into the plasma chamber, vacuumize, adjust the plasma power to 10W, and treat the front and back sides for 10 minutes. The first precursor of trimethylaluminum (TMA), deionized water (H 2 O) is the second precursor, and argon (Ar) is used as the carrier gas and sweep gas. The pulse times of the two precursors were 0.015s and 0.5s, respectively, the exposure times of the precursors were 10s and 50s, and the cleaning times were 30s and 60s, respectively. Heat the temperature of the reaction chamber to 70°C, keep the membrane at the set temperature of the reaction chamber for 5 minutes, and prepare modified membranes with 20, 50, 80, and 100 cycles respectively.

[0034] The surface-modified membrane in this example was observed and analyzed by scanning electron microscope. The membrane pore size decreased with the increase of deposition times, and the hydrophilic angle changed from the original 131° to 70±4°, 35±5°, 15±...

Embodiment 3

[0035] Example 3: First, put the PTFE separation membrane into the plasma chamber, vacuumize, adjust the plasma power to 300W, and treat the front and back sides for 1 minute. Titanium tetrachloride (TiCl 4 ) as the first precursor, ozone (O 3 ) is the second precursor, and argon (Ar) is used as the carrier gas and sweep gas. The pulse time of the two precursors was 0.015 s and 1 s, the exposure time of the precursor was 0 s, and the cleaning time was 10 s and 5 s, respectively. Heat the temperature of the reaction chamber to 200° C., keep the membrane at the set temperature of the reaction chamber for 1 min, and prepare a modified membrane with 500 cycles.

[0036] The static water contact angle of the modified membrane was characterized as 28±5°, the flux of pure water increased by 19%, and the rejection rate of silica microspheres increased by 64%.

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Abstract

The invention relates to a surface modification method for a polytetrafluoroethylene separation membrane. The method comprises the following steps of: activating the surface of the PTFE (polytetrafluoroethylene) membrane by virtue of a plasma technology, and then continuously depositing thin oxide layers on the surfaces of pore channels of the separation membrane by virtue of an atomic layer deposition technology to realize precise adjustment and control on pore diameter and surface properties of the separation membrane. According to the method, the plasma technology is used for pretreating, and then the atomic layer deposition is carried out, so that the growth mechanism of a deposition layer on the surface of the PTFE membrane is changed, the island type growthof the deposition layer is changed to conformal growth, the deposition layer is uniform and smooth, and the hydrophily, the pure water flux, the separating property and the anti-pollution capacity of the separation membrane are all obviously improved.

Description

technical field [0001] The invention relates to a separation membrane modification technology, in particular to a method for modifying the surface of a polytetrafluoroethylene separation membrane. Background technique [0002] PTFE is a very important engineering plastic due to its excellent chemical and physical properties. It is used in many fields and is also an important membrane material. However, there will be two problems when dealing with aqueous phase separation: one is strong hydrophobicity, which requires a large driving force for separation, high energy consumption, and low flux; Shortened lifespan. [0003] Researchers at home and abroad have done a lot of research on the surface modification of PTFE membranes, including high-energy radiation grafting modification, plasma treatment modification, chemical treatment modification, high temperature melting method, ion beam implantation modification, filling modification Wait. These methods have their own advantag...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/36B01D67/00
Inventor 汪勇许强
Owner NANJING UNIV OF TECH
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