CN117899669A - Preparation method of hydrophilic PTFE porous membrane - Google Patents
Preparation method of hydrophilic PTFE porous membrane Download PDFInfo
- Publication number
- CN117899669A CN117899669A CN202410313557.4A CN202410313557A CN117899669A CN 117899669 A CN117899669 A CN 117899669A CN 202410313557 A CN202410313557 A CN 202410313557A CN 117899669 A CN117899669 A CN 117899669A
- Authority
- CN
- China
- Prior art keywords
- porous membrane
- ptfe porous
- hydrophilic
- persulfate
- catechol
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000012528 membrane Substances 0.000 title claims abstract description 154
- 229920001343 polytetrafluoroethylene Polymers 0.000 title claims abstract description 118
- 239000004810 polytetrafluoroethylene Substances 0.000 title claims abstract description 118
- 238000002360 preparation method Methods 0.000 title abstract description 22
- 239000000243 solution Substances 0.000 claims abstract description 67
- YCIMNLLNPGFGHC-UHFFFAOYSA-N catechol Chemical compound OC1=CC=CC=C1O YCIMNLLNPGFGHC-UHFFFAOYSA-N 0.000 claims abstract description 60
- 238000010438 heat treatment Methods 0.000 claims abstract description 24
- 238000001035 drying Methods 0.000 claims abstract description 22
- 229920002873 Polyethylenimine Polymers 0.000 claims abstract description 19
- JRKICGRDRMAZLK-UHFFFAOYSA-L peroxydisulfate Chemical compound [O-]S(=O)(=O)OOS([O-])(=O)=O JRKICGRDRMAZLK-UHFFFAOYSA-L 0.000 claims abstract description 19
- 150000001263 acyl chlorides Chemical class 0.000 claims abstract description 17
- 239000007983 Tris buffer Substances 0.000 claims abstract description 16
- LENZDBCJOHFCAS-UHFFFAOYSA-N tris Chemical compound OCC(N)(CO)CO LENZDBCJOHFCAS-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000003960 organic solvent Substances 0.000 claims abstract description 10
- 238000003756 stirring Methods 0.000 claims abstract description 6
- 238000002156 mixing Methods 0.000 claims abstract description 4
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 18
- CNPVJWYWYZMPDS-UHFFFAOYSA-N 2-methyldecane Chemical group CCCCCCCCC(C)C CNPVJWYWYZMPDS-UHFFFAOYSA-N 0.000 claims description 11
- UWCPYKQBIPYOLX-UHFFFAOYSA-N benzene-1,3,5-tricarbonyl chloride Chemical compound ClC(=O)C1=CC(C(Cl)=O)=CC(C(Cl)=O)=C1 UWCPYKQBIPYOLX-UHFFFAOYSA-N 0.000 claims description 11
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 claims description 9
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 claims description 9
- 229910001870 ammonium persulfate Inorganic materials 0.000 claims description 9
- 239000002904 solvent Substances 0.000 claims description 7
- CTSLXHKWHWQRSH-UHFFFAOYSA-N oxalyl chloride Chemical compound ClC(=O)C(Cl)=O CTSLXHKWHWQRSH-UHFFFAOYSA-N 0.000 claims description 6
- PASDCCFISLVPSO-UHFFFAOYSA-N benzoyl chloride Chemical compound ClC(=O)C1=CC=CC=C1 PASDCCFISLVPSO-UHFFFAOYSA-N 0.000 claims description 5
- LCPVQAHEFVXVKT-UHFFFAOYSA-N 2-(2,4-difluorophenoxy)pyridin-3-amine Chemical compound NC1=CC=CN=C1OC1=CC=C(F)C=C1F LCPVQAHEFVXVKT-UHFFFAOYSA-N 0.000 claims description 4
- 238000005470 impregnation Methods 0.000 claims description 4
- USHAGKDGDHPEEY-UHFFFAOYSA-L potassium persulfate Chemical compound [K+].[K+].[O-]S(=O)(=O)OOS([O-])(=O)=O USHAGKDGDHPEEY-UHFFFAOYSA-L 0.000 claims description 4
- 230000035484 reaction time Effects 0.000 claims description 4
- CHQMHPLRPQMAMX-UHFFFAOYSA-L sodium persulfate Substances [Na+].[Na+].[O-]S(=O)(=O)OOS([O-])(=O)=O CHQMHPLRPQMAMX-UHFFFAOYSA-L 0.000 claims description 4
- VGCXGMAHQTYDJK-UHFFFAOYSA-N Chloroacetyl chloride Chemical compound ClCC(Cl)=O VGCXGMAHQTYDJK-UHFFFAOYSA-N 0.000 claims description 3
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 3
- WETWJCDKMRHUPV-UHFFFAOYSA-N acetyl chloride Chemical compound CC(Cl)=O WETWJCDKMRHUPV-UHFFFAOYSA-N 0.000 claims description 3
- 239000012346 acetyl chloride Substances 0.000 claims description 3
- VLKZOEOYAKHREP-UHFFFAOYSA-N hexane Substances CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- PVFOMCVHYWHZJE-UHFFFAOYSA-N trichloroacetyl chloride Chemical compound ClC(=O)C(Cl)(Cl)Cl PVFOMCVHYWHZJE-UHFFFAOYSA-N 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 60
- 238000006243 chemical reaction Methods 0.000 abstract description 38
- 230000004048 modification Effects 0.000 abstract description 26
- 238000012986 modification Methods 0.000 abstract description 26
- 239000002253 acid Substances 0.000 abstract description 10
- 239000003513 alkali Substances 0.000 abstract description 10
- 239000007800 oxidant agent Substances 0.000 abstract description 8
- 230000001590 oxidative effect Effects 0.000 abstract description 5
- 238000007598 dipping method Methods 0.000 abstract description 2
- 230000001737 promoting effect Effects 0.000 abstract description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 37
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 33
- 230000004907 flux Effects 0.000 description 23
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 22
- 238000004132 cross linking Methods 0.000 description 18
- 238000000576 coating method Methods 0.000 description 17
- 230000000052 comparative effect Effects 0.000 description 17
- 239000011248 coating agent Substances 0.000 description 16
- 238000002791 soaking Methods 0.000 description 14
- 238000004140 cleaning Methods 0.000 description 11
- 230000000694 effects Effects 0.000 description 10
- 238000005406 washing Methods 0.000 description 9
- 238000010521 absorption reaction Methods 0.000 description 8
- 235000019441 ethanol Nutrition 0.000 description 8
- 239000011148 porous material Substances 0.000 description 8
- 239000003431 cross linking reagent Substances 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- 239000010410 layer Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 4
- 239000003607 modifier Substances 0.000 description 4
- 238000004506 ultrasonic cleaning Methods 0.000 description 4
- NGNBDVOYPDDBFK-UHFFFAOYSA-N 2-[2,4-di(pentan-2-yl)phenoxy]acetyl chloride Chemical compound CCCC(C)C1=CC=C(OCC(Cl)=O)C(C(C)CCC)=C1 NGNBDVOYPDDBFK-UHFFFAOYSA-N 0.000 description 3
- 239000003153 chemical reaction reagent Substances 0.000 description 3
- 239000008367 deionised water Substances 0.000 description 3
- 229910021641 deionized water Inorganic materials 0.000 description 3
- 230000035699 permeability Effects 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 238000010998 test method Methods 0.000 description 3
- 230000004584 weight gain Effects 0.000 description 3
- 235000019786 weight gain Nutrition 0.000 description 3
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- 150000001408 amides Chemical class 0.000 description 2
- 125000003277 amino group Chemical group 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 239000012510 hollow fiber Substances 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000003999 initiator Substances 0.000 description 2
- 238000009832 plasma treatment Methods 0.000 description 2
- -1 polytetrafluoroethylene Polymers 0.000 description 2
- 238000002203 pretreatment Methods 0.000 description 2
- 238000000108 ultra-filtration Methods 0.000 description 2
- BRLQWZUYTZBJKN-UHFFFAOYSA-N Epichlorohydrin Chemical compound ClCC1CO1 BRLQWZUYTZBJKN-UHFFFAOYSA-N 0.000 description 1
- 241000237536 Mytilus edulis Species 0.000 description 1
- 230000003373 anti-fouling effect Effects 0.000 description 1
- 238000000231 atomic layer deposition Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- RWCCWEUUXYIKHB-UHFFFAOYSA-N benzophenone Chemical group C=1C=CC=CC=1C(=O)C1=CC=CC=C1 RWCCWEUUXYIKHB-UHFFFAOYSA-N 0.000 description 1
- 239000012965 benzophenone Substances 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 238000002715 modification method Methods 0.000 description 1
- 235000020638 mussel Nutrition 0.000 description 1
- 229920006254 polymer film Polymers 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 239000012286 potassium permanganate Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 229910021642 ultra pure water Inorganic materials 0.000 description 1
- 239000012498 ultrapure water Substances 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Landscapes
- Separation Using Semi-Permeable Membranes (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
Abstract
The invention relates to the technical field of porous membrane water treatment, in particular to a preparation method of a hydrophilic PTFE porous membrane, which comprises the following steps: s1, putting catechol, polyethyleneimine and persulfate into a Tris buffer solution, stirring and uniformly mixing, then putting into a pretreated PTFE porous membrane, and reacting for 1-6 hours to obtain a modified PTFE porous membrane; s2, immersing the modified PTFE porous membrane in an organic solvent containing an acyl chloride compound; s3, heating and drying the impregnated PTFE porous membrane to obtain the hydrophilic PTFE porous membrane, wherein in the preparation method provided by the invention, the persulfate oxidant is used for promoting the reaction, so that the modification time of the PTFE porous membrane is effectively shortened; meanwhile, the acyl chloride compound is crosslinked with the hydrophilic modified layer in a dipping heat treatment mode, so that the stability and acid and alkali resistance of the hydrophilic PTFE porous membrane are effectively improved.
Description
Technical Field
The invention relates to the technical field of porous membrane water treatment, in particular to a preparation method of a hydrophilic PTFE porous membrane.
Background
Organic films are the most widely used films in industrial processes because of their high bulk density, small footprint and light weight characteristics. Among the organic films, the porous polytetrafluoroethylene film exhibits excellent chemical stability, high heat resistance, strong hydrophobicity, and high fracture toughness. However, the practical use of PTFE membranes is limited mainly by two significant problems: a single pore structure and wettability. The membrane pores of the membrane contactor are large, the distribution is wide, the membrane is easy to wet, the pollution problem in water treatment can be caused by strong single-layer hydrophobicity, the membrane wetting and scaling can reduce the separation efficiency, the membrane performance and even failure, and therefore the operation cost is increased. The hydrophilic modification of PTFE membrane can raise the water flux and antifouling performance of the separating membrane in water treatment and prolong the service life.
The currently reported hydrophilic modification method of the porous membrane mainly comprises physical coating, plasma treatment, radiation, atomic layer deposition and the like. By these methods, the hydrophilicity of the porous film can be significantly improved, and most of the above techniques have some drawbacks. For example, the stability of the physical coating cannot be effectively guaranteed due to relatively poor compatibility between interfaces; the hydrophilicity produced by plasma treatment generally decreases over time; meanwhile, chemical corrosion easily damages the structure of the polytetrafluoroethylene membrane, thereby affecting the mechanical properties of the porous membrane. In recent years, mussel chemistry has made significant progress in hydrophilization of polymer film materials with its simple coating process, controllable surface morphology, and versatility. However, the stability of the coating over long periods of time and in harsh environments is worthy of further investigation.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, and provides a preparation method of a hydrophilic PTFE porous membrane, which has the characteristics of short modification time, good hydrophilic effect and good stability.
In order to achieve the technical effects, the invention adopts the following technical scheme:
a method for preparing a hydrophilic PTFE porous membrane, comprising the steps of:
s1, putting catechol, polyethyleneimine and persulfate into a Tris buffer solution, stirring and uniformly mixing, then putting into a pretreated PTFE porous membrane, and reacting for 1-6 hours to obtain a modified PTFE porous membrane;
s2, immersing the modified PTFE porous membrane in an organic solvent containing an acyl chloride compound;
s3, heating and drying the impregnated PTFE porous membrane to obtain a hydrophilic PTFE porous membrane,
The persulfate is selected from one or more of ammonium persulfate, sodium persulfate and potassium persulfate,
The mass ratio of catechol to polyethyleneimine to persulfate is 1 (0.5-2) to 1-2,
After the solution is put into the reactor, the mass fraction of catechol is 0.05 to 0.4 percent.
In the preparation method provided by the invention, the persulfate oxidant is used for promoting the reaction, so that the modification time of the PTFE porous membrane is effectively shortened; meanwhile, the acyl chloride compound is crosslinked with the hydrophilic modified layer in a dipping heat treatment mode, so that the stability and acid and alkali resistance of the hydrophilic PTFE porous membrane are effectively improved.
Preferably, in the step S1, the pretreatment method of the PTFE porous membrane is to put the PTFE porous membrane into absolute ethyl alcohol for ultrasonic cleaning, so as to remove solvent oil and surface impurities remained in the preparation process of the PTFE porous membrane, and wash the PTFE porous membrane with deionized water after cleaning. Further preferably, the ultrasonic cleaning time period is 1 hour.
Preferably, in the step S1, the pH of the Tris buffer solution is 8.5, the mass ratio of catechol, polyethyleneimine and persulfate is 1:1:2, and the mass fraction of catechol is 0.2%.
Preferably, in the step S1, the reaction time period is 4 h.
Preferably, in the step S2, the acyl chloride compound is selected from any one or more of acetyl chloride, benzoyl chloride, oxalyl chloride, chloroacetyl chloride, and trichloroacetyl chloride; the organic solvent is selected from one or more of acetonitrile, dichloromethane, N-dimethylformamide, N-hexane and isoparaffin solvent oil; the concentration of the acyl chloride compound is 0.1-0.6 wt%.
Further preferably, the acyl chloride compound is trimesoyl chloride in benzoyl chloride, the organic solvent is Isopar G (isoparaffin) in isoparaffin solvent oil, and the concentration of the acyl chloride compound is 0.4 wt%.
Preferably, in the step S2, the impregnation time is 1-4 min; further preferably, the impregnation time period is 3 min.
Preferably, in the step S3, the heating and drying temperature is 40-80 ℃, and the heating and drying time is 10-60min. Further preferably, the heating and drying temperature is 50-60 ℃, and the heating and drying time is 30-40 min.
Preferably, the pore size of the PTFE porous membrane is 0.05 μm to 2.0 μm and the porosity is 20% to 80%.
According to the preparation method provided by the application, the catechol modification rate is improved by using the persulfate oxidant. And the crosslinking agent of acyl chloride compound type is selected, so that the crosslinking in the application is more similar to the modification on the functional group, and the amine group on the original film surface is changed into amide to increase the stability of the hydrophilic layer, and the capability of changing the catechol hydrophilic layer structure is smaller.
The invention has the beneficial effects that:
1. the method has the advantages of short modification time, good single-time modification hydrophilic effect, higher efficiency, easier mass production, and more convenience in operation, and particularly, the persulfate oxidant is used for improving the catechol modification rate, and the acyl chloride compound type cross-linking agent is selected to change the amine group on the original film surface into the amide so as to increase the stability of the hydrophilic layer, and meanwhile, the structure of the catechol hydrophilic layer is not influenced;
2. The hydrophilic PTFE porous membrane prepared by the preparation method provided by the invention has good stability, the hydrophilic layer is stable and does not fall off, the hydrophilic PTFE porous membrane can be used in strong acid and strong alkali environments, and the excellent performance of the PTFE membrane can be fully exerted.
Drawings
FIG. 1 is a graph showing the water contact angle before and after hydrophilic modification of the hydrophilic PTFE porous membrane prepared in example 4;
FIG. 2 is a graph showing the dynamic water contact angle of the hydrophilic PTFE porous membrane prepared in example 4;
FIG. 3 is a scanning electron microscope image of the hydrophilic PTFE porous membrane produced in example 4, wherein FIG. 3 (1) is before hydrophilic modification and FIG. 3 (2) is after hydrophilic modification.
Detailed Description
The invention will be further described with reference to examples and figures.
The invention provides a preparation method of a hydrophilic PTFE porous membrane, which comprises the following steps:
S1, putting catechol, polyethyleneimine and persulfate into a Tris buffer solution, stirring and uniformly mixing, then putting into a pretreated PTFE porous membrane, and reacting to obtain a modified PTFE porous membrane;
s2, immersing the modified PTFE porous membrane in an organic solvent containing an acyl chloride compound;
s3, heating and drying the impregnated PTFE porous membrane, and washing with absolute ethyl alcohol to obtain the hydrophilic PTFE porous membrane.
In the step S1, the pretreatment method of the PTFE porous membrane is to put the PTFE porous membrane into absolute ethyl alcohol for ultrasonic cleaning so as to remove solvent oil and surface impurities remained in the preparation process of the PTFE porous membrane, and wash the PTFE porous membrane with deionized water after cleaning. Further preferably, the PTFE porous membrane has a pore size of 0.05 μm to 2.0 μm, a porosity of 20 to 80%, and an ultrasonic cleaning time period of 1h.
In the step S1, persulfate is selected from any one or more of ammonium persulfate, sodium persulfate and potassium persulfate, the mass ratio of catechol, polyethyleneimine and persulfate is 1 (0.5-2) (1-2), the pH value of Tris buffer solution is 8.5, and the mass fraction of catechol after the solution is put into the solution is 0.05-0.4%; further preferably, the mass ratio of catechol, polyethyleneimine and persulfate is 1:1:2, and the mass fraction of catechol is 0.2%.
Experiments prove that in the selected mass fraction and mass proportion range, good modification effects can be realized for PTFE porous membranes with the total mass of 20g/50g/100g in the same concentration modification solution by using catechol solution with the same concentration, and the performance parameters have no large difference.
In the step S1, the reaction time is 1-6 h; further preferably, the reaction time is 4 h.
In the step S2, the acyl chloride compound is selected from any one or more of acetyl chloride, benzoyl chloride, oxalyl chloride, chloroacetyl chloride and trichloroacetyl chloride; the organic solvent is selected from one or more of acetonitrile, dichloromethane, N-dimethylformamide, N-hexane and isoparaffin solvent oil; the concentration of the acid chloride compound is 0.1-0.6%. Further preferably, the acid chloride compound is selected from trimesoyl chloride and the organic solvent is selected from Isopar G, the concentration of the acid chloride compound being 0.4 wt%.
In the step S2, the soaking time is 1-4min; further preferably, the impregnation time period is 3 min.
In the step S3, the heating and drying temperature is 40-80 ℃, and the heating and drying time is 10-60min. Further preferably, the heating and drying temperature is 60 ℃, and the heating and drying time is 30 min.
The PTFE porous membranes used in the following examples and comparative examples were PTFE porous membranes having a porosity of 75%, a pore size of 0.6 μm and a mass of 20g, and were manufactured by Shandong eastern mountain polymer materials Co., ltd.
The reagents and test equipment used are all the conventional commercially available common reagents and test equipment.
Example 1
A preparation method of a hydrophilic PTFE porous membrane comprises the following specific steps:
s1, completely soaking the PTFE porous membrane in absolute ethyl alcohol in an ultrasonic cleaner and then cleaning the PTFE porous membrane to 1h.
S2. 0.5g catechol and 1 g polyethyleneimine are added into 500 ml Tris buffer solution (ph=8.5) and fully dissolved into modified solution. The infiltrated PTFE porous membrane was transferred to a reaction vessel containing the modified solution, and then 0.5g of ammonium persulfate was added thereto, followed by stirring for reaction 6 h.
S3, adding 0.5 g trimesic acid chloride into 500 ml Isopar G, and fully dissolving to obtain a crosslinking solution. Immersing the film modified in the step S2 into a crosslinking solution for reaction 2 min.
S4, placing the membrane after the reaction in the step S3 into a baking oven at 40 ℃ for heat treatment of 40 min, fully washing with absolute ethyl alcohol, and drying to obtain the hydrophilic PTFE porous membrane.
The water contact angle of the prepared hydrophilic PTFE porous membrane is 52 degrees, and the water flux is 3550L m -2·h-1 measured at 0.05 MPa; the film surface contact angle is measured to be 61 degrees by soaking 2h in 0.01 mol/L hydrochloric acid and sodium hydroxide solution respectively, and the contact angle is not obviously increased, so that the coating has good stability and acid and alkali resistance.
Example 2
A preparation method of a hydrophilic PTFE porous membrane comprises the following specific steps:
s1, completely soaking the PTFE porous membrane in ethanol in an ultrasonic cleaner and then cleaning 1 h.
S2, adding 1g catechol and 1g polyethyleneimine into a 500 ml Tris buffer solution (pH=8.5) to fully dissolve the materials into a modified solution. The infiltrated PTFE porous membrane is transferred to a reaction vessel containing the modified solution, and then 1g ammonium persulfate is added and stirred for reaction 3 h.
S3, adding 1g trimesic acid chloride into 500 ml Isopar G, and fully dissolving to obtain a crosslinking solution. Immersing the film modified in the step S2 into a crosslinking solution for reaction 5 min.
S4, placing the membrane after the reaction in the step S3 into a baking oven at 60 ℃ for heat treatment for 30min, fully washing with absolute ethyl alcohol, and drying to obtain the hydrophilic PTFE porous membrane.
The water contact angle of the prepared hydrophilic PTFE porous membrane is 51 degrees, and the water flux is 3470L m -2·h-1 measured at 0.05 MPa; the film surface contact angle is measured to be 61 degrees by soaking 2h in 0.01 mol/L hydrochloric acid and sodium hydroxide solution respectively, and the contact angle is not obviously increased, so that the coating has good stability and acid and alkali resistance.
Example 3
A preparation method of a hydrophilic PTFE porous membrane comprises the following specific steps:
s1, completely soaking the PTFE porous membrane in ethanol in an ultrasonic cleaner and then cleaning 1 h.
S2, adding 2g catechol and 1g polyethyleneimine into a 500 ml Tris buffer solution (pH=8.5) and fully dissolving to obtain a modified solution. The infiltrated PTFE porous membrane is transferred to a reaction vessel containing the modified solution, then 2g ammonium persulfate is added, and the reaction is stirred for 4h.
S3, adding 2 g trimesic acid chloride into 500 ml Isopar G, and fully dissolving to obtain a crosslinking solution. Immersing the film modified in the step S2 into a crosslinking solution for reaction 2 min.
S4, placing the membrane after the reaction in the step S3 into an oven at 80 ℃ for heat treatment of 20min, fully washing with absolute ethyl alcohol, and drying to obtain the hydrophilic PTFE porous membrane.
The water contact angle of the prepared PTFE porous membrane is 54 degrees, and the water flux is 3396L m -2·h-1 measured at 0.05 MPa; the contact angle of the film surface is 63 degrees after being soaked in 0.01 mol/L hydrochloric acid and sodium hydroxide solution for 2h respectively, which shows that the coating has good stability and acid and alkali resistance.
Example 4
A preparation method of a hydrophilic PTFE porous membrane comprises the following specific steps:
s1, completely soaking the PTFE porous membrane in ethanol in an ultrasonic cleaner and then cleaning 1 h.
S2. 2.2 g catechol and 2g polyethyleneimine are added into 500 ml Tris buffer solution (ph=8.5) and fully dissolved into modified solution. The infiltrated PTFE porous membrane is transferred to a reaction vessel containing the modified solution, then 4 g sodium persulfate is added, and the reaction is stirred for 2h.
S3, adding 2 g trimesic acid chloride into 500 ml Isopar G, and fully dissolving to obtain a crosslinking solution. Immersing the film modified in the step S2 into a crosslinking solution for reaction 4 min.
S4, placing the membrane after the reaction in the step S3 into a baking oven at 60 ℃ for heat treatment for 30min, fully washing with absolute ethyl alcohol, and drying to obtain the hydrophilic PTFE porous membrane.
As shown in fig. 1-3, the water contact angle of the prepared PTFE porous membrane was 49 °, and the water flux was 3574L ·m -2·h-1 measured at 0.05 MPa; the contact angle of the film surface is 57 degrees by soaking 2 h in 0.01 mol/L hydrochloric acid and sodium hydroxide solution, and the contact angle is not obviously increased, so that the coating has good stability and acid and alkali resistance.
Example 5
A preparation method of a hydrophilic PTFE porous membrane comprises the following specific steps:
s1, completely soaking the PTFE porous membrane in ethanol in an ultrasonic cleaner and then cleaning 1 h.
S2. 2.2 g catechol and 2g polyethyleneimine are added into 500 ml Tris buffer solution (ph=8.5) and fully dissolved into modified solution. The infiltrated PTFE porous membrane is transferred to a reaction vessel containing the modified solution, then 4 g potassium persulfate is added, and the reaction is stirred for 2h.
S3, adding 2 g trimesic acid chloride into 500 ml Isopar G, and fully dissolving to obtain a crosslinking solution. Immersing the film modified in the step S2 into a crosslinking solution for reaction 4 min.
S4, placing the membrane after the reaction in the step S3 into a baking oven at 60 ℃ for heat treatment for 30min, fully washing with absolute ethyl alcohol, and drying to obtain the hydrophilic PTFE porous membrane.
The water contact angle of the prepared PTFE porous membrane is 49 degrees, and the water flux is 3552L m -2·h-1 measured at 0.05 MPa; the film surface contact angle is measured to be 58 degrees by soaking 2h in 0.01 mol/L hydrochloric acid and sodium hydroxide solution in sequence, and the contact angle is not obviously increased, which indicates that the variation of the persulfate type has little difference on the modification rate and the coating stability.
Comparative example 1
The preparation method of the PTFE porous membrane comprises the following specific steps:
s1, completely soaking the PTFE porous membrane in ethanol in an ultrasonic cleaner and then cleaning 1 h.
S2. 0.05 g catechol and 0.5 g polyethyleneimine are added into 500 ml Tris buffer solution (ph=8.5) and fully dissolved into modified solution. The infiltrated PTFE porous membrane is transferred to a reaction vessel containing the modified solution, then 4 g ammonium persulfate is added, and the reaction is stirred for 3 h.
S3, adding 2 g trimesic acid chloride into 500 ml Isopar G, and fully dissolving to obtain a crosslinking solution. Immersing the film modified in the step S2 into a crosslinking solution for reaction 4 min.
S4, placing the membrane after the reaction in the step S3 into a baking oven at 60 ℃ for heat treatment for 30 min, fully washing with absolute ethyl alcohol, and drying to obtain the PTFE porous membrane.
The water contact angle of the prepared PTFE porous membrane is 82 degrees, and the water flux is 1397L m -2·h-1 measured at 0.05 MPa, which shows that the modifying ability to membrane wires is poor under the condition of low modifying agent concentration.
Comparative example 2
The preparation method of the PTFE porous membrane comprises the following specific steps:
s1, completely soaking the PTFE porous membrane in ethanol in an ultrasonic cleaner and then cleaning 1 h.
S2. 2.2 g catechol and 2g polyethyleneimine are added into 500 ml Tris buffer solution (ph=8.5) and fully dissolved into modified solution. The infiltrated PTFE porous membrane was transferred to a reaction vessel containing the modification solution and stirred for reaction 6h.
S3, adding 1g trimesic acid chloride into 500 ml Isopar G, and fully dissolving to obtain a crosslinking solution. Immersing the film modified in the step S2 into a crosslinking solution for reaction 2 min.
S4, placing the membrane after the reaction in the step S3 into a baking oven at 60 ℃ for heat treatment for 30 min, fully washing with absolute ethyl alcohol, and drying to obtain the PTFE porous membrane.
Through testing, the water contact angle of the prepared PTFE porous membrane is 96 degrees, which shows that under the condition of no initiator or too low initiator concentration, the hydrophilic modifier reacts too slowly, the modifying capability on membrane filaments is weaker, and the hydrophilicity of the modified membrane is poorer.
Comparative example 3
The preparation method of the PTFE porous membrane comprises the following specific steps:
s1, completely soaking the PTFE porous membrane in ethanol in an ultrasonic cleaner and then cleaning 1 h.
S2, adding 1g catechol and 1g polyethyleneimine into a 500 ml Tris buffer solution (pH=8.5) to fully dissolve the materials into a modified solution. The infiltrated PTFE porous membrane is transferred to a reaction vessel containing the modified solution, then 0.5 g ammonium persulfate is added, and the reaction is stirred for 3 h.
S3, the membrane after the reaction in the step S2 is placed into a baking oven at 60 ℃ to be treated for 8 min, and is fully washed by absolute ethyl alcohol and then dried, so that the PTFE porous membrane is obtained.
The water contact angle of the prepared PTFE porous membrane is 57 degrees, and the water flux is 3471L m -2·h-1 measured at 0.05 MPa; the contact angle of the film surface is 113 degrees after being soaked in 0.01 mol/L hydrochloric acid and sodium hydroxide solution for 2h respectively, and the contact angle is obviously increased, which indicates that the uncrosslinked or incompletely crosslinked coating is easy to decompose under acid and alkali.
Comparative example 4
The preparation method of the PTFE porous membrane comprises the following specific steps:
s1, completely soaking the PTFE porous membrane in ethanol in an ultrasonic cleaner and then cleaning 1 h.
S2, adding 3g catechol and 4 g polyethyleneimine into a 500 ml Tris buffer solution (pH=8.5) and fully dissolving to obtain a modified solution. The infiltrated PTFE porous membrane was transferred to a reaction vessel containing the modified solution, and then 3g of ammonium persulfate was added thereto, followed by stirring for reaction 2 h.
S3, adding 0.5 g trimesic acid chloride into 500 ml Isopar G, and fully dissolving to obtain a crosslinking solution. Immersing the film modified in the step S2 into a crosslinking solution for reaction 4 min.
S4, placing the membrane after the reaction in the step S3 into a baking oven at 60 ℃ for heat treatment of 20min, fully washing with absolute ethyl alcohol, and drying to obtain the PTFE porous membrane.
The water contact angle of the prepared PTFE porous membrane is 48 degrees, and the water flux is 3061L m -2·h-1 measured at 0.05 MPa; immersing 2.2 h in 0.01 mol/L hydrochloric acid and sodium hydroxide solution respectively, and measuring the contact angle of the surface of the film to be 57 degrees; the method shows that the pore diameter of the membrane is easy to be blocked under the condition of higher concentration of the modifier, so that the water flux is reduced, and the filtration efficiency is influenced.
Comparative example 5
A method for preparing a PTFE porous membrane is different from example 5 in that the same amount of potassium permanganate is used as the oxidant, and the other steps are the same.
Through testing, the water contact angle of the prepared PTFE porous membrane is 52 degrees, and the water flux is 2914L m -2·h-1 measured at 0.05 MPa; the contact angle of the film surface was measured to be 61 ° by immersing 2h each in 0.01 mol/L of hydrochloric acid and then in sodium hydroxide solution.
Comparative example 6
A porous PTFE membrane was prepared by the same procedure as in example 5 except that equal amounts of epichlorohydrin were used as the crosslinking agent.
The water contact angle of the prepared PTFE porous membrane is 64 degrees, and the water flux is 2457L m -2·h-1 measured at 0.05 MPa; the film surface contact angle was measured to be 67 ° by immersing 2h each in 0.01 mol/L hydrochloric acid and then in sodium hydroxide solution.
Comparative example 7
A method for preparing a PTFE porous membrane is different from example 5 in that the same amount of hydrogen peroxide is used as the oxidizing agent, and the other steps are the same.
Through testing, the water contact angle of the prepared PTFE porous membrane is 65 degrees, and the water flux is 2769L m -2·h-1 measured at 0.05 MPa; the contact angle of the film surface was measured to be 69 ° by immersing 2h each in 0.01 mol/L hydrochloric acid and then in sodium hydroxide solution.
Comparative example 8
A method for preparing a PTFE porous membrane is different from example 5 in that the crosslinking agent is benzophenone in equal amount and the other steps are the same.
The water contact angle of the prepared PTFE porous membrane is 67 degrees, and the water flux is 2269L m -2·h-1 under the condition of 0.05 MPa; the contact angle of the film surface was measured to be 84 ° by immersing 2h each in 0.01 mol/L hydrochloric acid and then in sodium hydroxide solution.
The statistics of the measured data of the untreated PTFE porous membrane described above and the hydrophilic PTFE porous membranes produced in the examples and comparative examples are shown in the following table:
table 1 measured data
In the table, the water contact angle measurement method: the hydrophilicity of hollow fiber membranes was characterized by water contact angle, contact angle test using DATAPHYSICS OCA contact angle meter. The specific operation method comprises the following steps: deionized water is dripped on the surface of the film material to be measured by using a micro-injector, the value of the contact angle is recorded, three different positions are found on each sample to be measured, and the arithmetic average value is obtained from the three measured values.
The water absorption rate calculation method comprises the following steps: the water absorption of the control film and the modified film was determined by measuring the weight difference of the film sample before and after immersing in ultrapure water overnight. The water absorption is calculated by the formula:
(I)
In the formula (I), W is water absorption rate, and the unit is; m wet and M dry are the mass of the wet film and the mass of the dry film, respectively, in g, as measured by a METTLER TOLEDO XPR226CDR/AC analytical balance.
The water flux calculating method comprises the following steps: the water flux test method refers to GB/T32360-2015 ultrafiltration membrane test method and HY/T050-1999 hollow fiber ultrafiltration membrane test method, and the miniature membrane separation device used for the test is provided by Sifei membrane separation technology Co., hangzhou.
Among the properties, the water flux is most important, and the water flux can intuitively represent the influence of the water permeability of the membrane before and after modification, the contact angle and the water absorption rate can represent the wettability of the membrane before and after modification, the contact angle can represent the modification effect of the membrane surface, the water absorption rate can characterize the thickness of a membrane modified coating and the capability of modifying a membrane pore canal, the weight gain is the representation of the deposition thickness of the coating, the contact angle and the weight gain are the representation of the modification effect, and the water absorption rate and the water flux are the representation of the performance of the membrane in water treatment. Good modified membranes are required to have good hydrophilicity and water permeability.
As can be seen from the data in the table above,
The water contact angle, the water absorption, the weight gain and the water flux of the comparative example 1 are poor because the concentration of the modifier of the comparative example 1 is too low, so that a hydrophilic coating with enough thickness cannot be generated on the surface of the modified membrane, hydrophilic groups are too few, and the effect of the crosslinking agent is limited, so that the performance is poor.
The performance of comparative example 2 was poor because the modification time of comparative example 2 was too short, so that the film surface after modification could not generate a hydrophilic coating of sufficient thickness, the hydrophilic group was too few, and the effect of the crosslinking agent was limited, and thus the performance was poor.
The acid and alkali resistance of comparative example 3 is poor because the chemical stability of the coating is poor without the crosslinking treatment and the coating is easily decomposed under acid and alkali.
The flux of comparative example 4 is reduced because the concentration of the modifier is too high, and the generated modified coating is too thick, which blocks the original pore channels, increases the water mass transfer resistance, reduces the water flux, and affects the filtration efficiency.
The reagents described in comparative examples 5 to 8 are modification aids which have a positive effect on the modification effect, wherein the difference is that the reaction mechanism and the route of the modification process are different due to the difference of the oxidizing agent and the crosslinking agent, so that the water flux of the prepared porous membrane is inferior to that of the examples, and the persulfate oxidizing agent is extremely critical in the preparation process.
The hydrophilic PTFE porous membranes prepared in each example have good hydrophilicity, water permeability and stability, wherein the differences of the individual parameters are not visually influenced on the modification effect.
Claims (7)
1. A method for preparing a hydrophilic PTFE porous membrane, comprising the steps of:
s1, putting catechol, polyethyleneimine and persulfate into a Tris buffer solution, stirring and uniformly mixing, then putting into a pretreated PTFE porous membrane, and reacting for 1-6 hours to obtain a modified PTFE porous membrane;
s2, immersing the modified PTFE porous membrane in an organic solvent containing an acyl chloride compound;
s3, heating and drying the impregnated PTFE porous membrane to obtain a hydrophilic PTFE porous membrane,
The persulfate is selected from one or more of ammonium persulfate, sodium persulfate and potassium persulfate,
The mass ratio of catechol to polyethyleneimine to persulfate is 1 (0.5-2) to 1-2,
After the solution is put into the reactor, the mass fraction of catechol is 0.05 to 0.4 percent.
2. The method for preparing a porous membrane of hydrophilic PTFE according to claim 1, wherein in the step S1, the pH of the Tris buffer solution is 8.5, the mass ratio of catechol, polyethyleneimine and persulfate is 1:1:2, and the mass fraction of catechol is 0.2%.
3. The method for preparing a porous membrane of hydrophilic PTFE according to claim 1, wherein in step S1, the reaction time is 4 h.
4. The method for producing a hydrophilic PTFE porous membrane according to claim 1, wherein in said step S2,
The acyl chloride compound is selected from any one or more of acetyl chloride, benzoyl chloride, oxalyl chloride, chloroacetyl chloride and trichloroacetyl chloride;
the organic solvent is selected from one or more of acetonitrile, dichloromethane, N-dimethylformamide, N-hexane and isoparaffin solvent oil;
The concentration of the acyl chloride compound is 0.1-0.6 wt%.
5. The method for preparing a porous membrane of hydrophilic PTFE according to claim 4, wherein the acyl chloride compound is trimesoyl chloride in benzoyl chloride, the organic solvent is Isopar G in Isopar solvent oil, and the concentration of the acyl chloride compound is 0.4 wt%.
6. The method of preparing a porous membrane of hydrophilic PTFE according to claim 1, wherein the impregnation time in step S2 is 1 to 4 min.
7. The method for preparing a porous membrane of hydrophilic PTFE according to claim 1, wherein in step S3, the heating and drying temperature is 40 to 80 ℃ and the heating and drying time period is 10 to 60 minutes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410313557.4A CN117899669B (en) | 2024-03-19 | Preparation method of hydrophilic PTFE porous membrane |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410313557.4A CN117899669B (en) | 2024-03-19 | Preparation method of hydrophilic PTFE porous membrane |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN117899669A true CN117899669A (en) | 2024-04-19 |
| CN117899669B CN117899669B (en) | 2024-06-04 |
Family
ID=
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014200703A (en) * | 2013-04-01 | 2014-10-27 | ダイキン工業株式会社 | Porous polymer membrane and method for producing porous polymer membrane |
| CN105854638A (en) * | 2016-04-14 | 2016-08-17 | 中国科学院宁波材料技术与工程研究所 | Permanently hydrophilic PTFE hollow fiber membrane and preparation method thereof |
| CN106345307A (en) * | 2016-09-23 | 2017-01-25 | 浙江大学 | Hollow fiber composite nano-filtration membrane and preparation method thereof |
| KR20180053595A (en) * | 2016-11-11 | 2018-05-23 | 한국에너지기술연구원 | Ion exchange membrane using catechol-amine bond and method for manufacturing the same |
| CN110465211A (en) * | 2019-08-23 | 2019-11-19 | 哈尔滨工业大学 | One kind having the polyphenol functionalization composite membrane and preparation method thereof of " sandwich " interlayer structure separating layer |
| CN114307678A (en) * | 2022-02-17 | 2022-04-12 | 天津工业大学 | Preparation method of composite nanofiltration membrane based on zwitterion regulation and control |
| CN114588844A (en) * | 2022-03-18 | 2022-06-07 | 杭州师范大学 | Application of Shuangshen hollow fiber membrane reactor in Suzuki-Miyaura reaction and membrane reactor thereof |
| CN116440719A (en) * | 2023-03-09 | 2023-07-18 | 利得膜(北京)新材料技术有限公司 | Hydrophilized polytetrafluoroethylene hollow fiber microfiltration membrane and preparation method thereof |
| CN116826308A (en) * | 2023-08-31 | 2023-09-29 | 天津市捷威动力工业有限公司 | Composite diaphragm, preparation method thereof and secondary battery |
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014200703A (en) * | 2013-04-01 | 2014-10-27 | ダイキン工業株式会社 | Porous polymer membrane and method for producing porous polymer membrane |
| CN105854638A (en) * | 2016-04-14 | 2016-08-17 | 中国科学院宁波材料技术与工程研究所 | Permanently hydrophilic PTFE hollow fiber membrane and preparation method thereof |
| CN106345307A (en) * | 2016-09-23 | 2017-01-25 | 浙江大学 | Hollow fiber composite nano-filtration membrane and preparation method thereof |
| KR20180053595A (en) * | 2016-11-11 | 2018-05-23 | 한국에너지기술연구원 | Ion exchange membrane using catechol-amine bond and method for manufacturing the same |
| CN110465211A (en) * | 2019-08-23 | 2019-11-19 | 哈尔滨工业大学 | One kind having the polyphenol functionalization composite membrane and preparation method thereof of " sandwich " interlayer structure separating layer |
| CN114307678A (en) * | 2022-02-17 | 2022-04-12 | 天津工业大学 | Preparation method of composite nanofiltration membrane based on zwitterion regulation and control |
| CN114588844A (en) * | 2022-03-18 | 2022-06-07 | 杭州师范大学 | Application of Shuangshen hollow fiber membrane reactor in Suzuki-Miyaura reaction and membrane reactor thereof |
| CN116440719A (en) * | 2023-03-09 | 2023-07-18 | 利得膜(北京)新材料技术有限公司 | Hydrophilized polytetrafluoroethylene hollow fiber microfiltration membrane and preparation method thereof |
| CN116826308A (en) * | 2023-08-31 | 2023-09-29 | 天津市捷威动力工业有限公司 | Composite diaphragm, preparation method thereof and secondary battery |
Non-Patent Citations (1)
| Title |
|---|
| WEN-ZE QIU ET AL.: ""Codeposition of catechol–polyethyleneimine followed by interfacial polymerization for nanofiltration membranes with enhanced stability"", 《JOURNAL OF APPLIED POLYMER SCIENCE》, vol. 134, no. 42, 30 November 2017 (2017-11-30), pages 1 - 9 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4293765B2 (en) | Method for impregnating porous substrate | |
| CN109437147B (en) | Preparation method of multifunctional carbon foam | |
| CN112973653B (en) | Preparation method of Mxene membrane adsorbing material based on polyamidoxime and uranium extraction method | |
| CN107243262B (en) | High-flux anti-pollution polyamide composite reverse osmosis membrane and preparation method thereof | |
| CN109663510B (en) | Zwitterionic random copolymer P (MMA)x-r-CBMAy) Modified PVDF antifouling film and preparation method thereof | |
| CN115414801B (en) | Method for preparing durable hydrophilic polytetrafluoroethylene separation membrane by one-step method | |
| CN110124527A (en) | A kind of method that dopamine assistant depositing prepares high-throughput graphene oxide quantum dot composite nanometer filtering film | |
| CN117899669B (en) | Preparation method of hydrophilic PTFE porous membrane | |
| CN113621170A (en) | Anion exchange composite membrane and preparation method and application thereof | |
| JP3809201B2 (en) | Hydrophilic tetrafluoroethylene resin porous membrane and method for producing the same | |
| CN117899669A (en) | Preparation method of hydrophilic PTFE porous membrane | |
| CN111393709A (en) | Preparation method of long-acting hydrophilic polytetrafluoroethylene microporous membrane | |
| CN112619438B (en) | Methanol-resistant polyamide reverse osmosis membrane and preparation method thereof | |
| CN112619451A (en) | Preparation method of hydrophilic polytetrafluoroethylene hollow fiber microfiltration membrane | |
| CN117107297A (en) | Composite diaphragm for enhancing gas barrier property and used for alkaline water electrolysis hydrogen production and preparation method thereof | |
| CN109621740B (en) | Pore-diameter-controllable super-hydrophobic polymeric membrane and preparation method thereof | |
| KR20040062970A (en) | Fuel Cell Gas Diffusion Layer Coating Process and Treated Article | |
| WO2023033619A1 (en) | Fluorine-based polymer surface hydrophilic treatment method through plasma and silane treatment | |
| CN111477884A (en) | Organic modification hydrophobic treatment method for carbon fiber paper membrane of fuel cell | |
| CN114566753B (en) | Hydrogen production diaphragm material capable of improving ion migration performance and preparation method thereof | |
| CN111701462A (en) | Hydrophilic modification method of PTFE hollow fiber membrane | |
| CN114605918B (en) | Preparation method of oil stain self-desorption coating | |
| CN115572402B (en) | Super-hydrophobic coating on film surface and preparation method thereof | |
| CN116440719B (en) | Hydrophilized polytetrafluoroethylene hollow fiber microfiltration membrane and preparation method thereof | |
| CN114618328B (en) | Preparation method of PVDF (polyvinylidene fluoride) membrane with emulsion separation and dye adsorption performances |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant |