A pH responsive coating and a preparation method thereof, and a product

Abstract

The disclosed embodiment provides a pH responsive coating and a preparation method thereof, as well as a product. The pH responsive coating is a plasma polymerized coating formed by monomer α on at least part of the surface of a substrate, wherein the structure of the monomer α comprises a carbon-carbon double bond structure and a weakly alkaline structure comprising a nitrogen atom, wherein the nitrogen atom in the weakly alkaline structure comprising a nitrogen atom is located on a ring or connected to two secondary carbon atoms, and the pH responsive coating has good pH responsiveness and exhibits different properties in acidic and alkaline environments.

Description

Technical Field

[0001] The present disclosure relates to the field of coating technology, and in particular to a pH responsive coating and a preparation method thereof, and a product. Background Art

[0002] Stimuli-responsive surfaces have great potential in a wide range of engineering, scientific and industrial processes because of their unique switchable properties, often referred to as "smart" surfaces. The physicochemical properties of stimuli-responsive surfaces change in response to various physical or chemical stimuli in the environment. Once the stimulus that caused the change returns to its initial state, its changed physicochemical properties will also return to their initial state accordingly. In research, pH, temperature, light and magnetic field are the most common stimuli. The response mechanism of stimuli-responsive surfaces varies depending on the application.

[0003] pH responsive materials have unique properties and wide application potential. When the pH value of the medium or environment increases or decreases, the performance of the pH responsive materials will change. When pH responsive materials are used in coatings, the performance of the coating can be adjusted according to the pH value of the environment or contact medium, thus having great application prospects.

[0004] Therefore, the present invention aims to develop a pH responsive coating. Summary of the invention

[0005] An embodiment of the present disclosure provides a pH responsive coating, wherein the pH responsive coating is a plasma polymerized coating formed by a monomer α on at least a portion of the surface of a substrate, wherein the monomer α has a structure shown in formula (1),

[0006]

[0007] In formula (1), L is a connecting structure, R1 and R2 are independently selected from C1-C 10 An organic group or a hydrogen atom, R3 is selected from C1-C 10 An alkyl group or a hydrogen atom, T is selected from the structure represented by formula (2), formula (3), or formula (4),

[0008]

[0009] In formula (2), R4, R5, R6, and R7 are independently selected from C1-C 10 Alkyl; in formula (3), A is a cyclic structure; in formula (4), B is a cyclic structure.

[0010] In some embodiments, the C1-C 10 The organic group is selected from C1-C 10 Alkyl or C1-C 10 Alkoxy acyl.

[0011] In some embodiments, L is selected from C1-C4 alkylene, the structure shown in formula (5), or a connecting bond,

[0012]

[0013] In formula (5), R8 is selected from C1-C6 alkylene.

[0014] In some embodiments, R1, R2, and R3 are independently selected from C1-C4 alkyl or hydrogen atom; T is selected from the structure shown in formula (2), in which R4, R5, R6, and R7 are independently selected from methyl, ethyl, or propyl; L is selected from the structure shown in formula (5), in which R8 is selected from methylene, ethylene, or propylene.

[0015] In some embodiments, R1, R2, and R3 are independently selected from methyl or hydrogen atoms, and R4, R5, R6, and R7 are independently selected from methyl or ethyl.

[0016] In some embodiments, the T is selected from the structure shown in formula (3) or formula (4), in which the cyclic structure is a five-membered ring or a six-membered ring.

[0017] In some embodiments, the five-membered ring or six-membered ring is selected from the structures shown in formula (6) to formula (12),

[0018]

[0019] In formula (6), n is an integer of 1 to 2, and n R9 are independently selected from C1-C4 alkyl groups or hydrogen atoms; in formula (7), m is an integer of 1 to 3, and m R 10 are independently selected from C1-C4 alkyl, or hydrogen atom; in formula (8), a is an integer of 1 to 4, a R 11 are independently selected from C1-C4 alkyl, or hydrogen atom; in formula (9), b is an integer of 1 to 3, and b R 12 are independently selected from C1-C4 alkyl, or hydrogen atom; in formula (10), c is an integer of 1 to 3, and c R 13 are independently selected from C1-C4 alkyl, or hydrogen atom; in formula (11), d is an integer of 1 to 4, and d R 14 are independently selected from C1-C4 alkyl, or hydrogen atom; in formula (12), e is an integer from 1 to 3, and e R 15 Each is independently selected from a C1-C4 alkyl group, or a hydrogen atom.

[0020] In some embodiments, the L is selected from a connecting bond, and the R1, R2, and R3 are independently selected from a methyl group or a hydrogen atom.

[0021] In some embodiments, the L is selected from a connecting bond, the R1 is selected from a methyl group or a hydrogen atom, the R2 is selected from a methoxyformyl group or an ethoxyformyl group, and the R3 is selected from a methyl group or a hydrogen atom.

[0022] In some embodiments, the monomer α includes: one or more of: 2-(diisopropylamino)ethyl acrylate, 2-(diisopropylamino)ethyl methacrylate, 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, 3-(pyridin-3-yl)ethyl acrylate, and 3-(4-pyridinyl)methyl acrylate.

[0023] In some embodiments, the contact angle of an aqueous solution with a pH of 3.5 to 5 on the pH responsive coating is less than 30°.

[0024] In some embodiments, the contact angle of an aqueous solution with a pH of 3.5 to 5 on the pH responsive coating is less than 5°.

[0025] In some embodiments, the substrate comprises: silicon, glass, PET, fabric, filter paper.

[0026] The embodiments of the present disclosure also provide a method for preparing a pH responsive coating, which is used to prepare any of the above pH responsive coatings, and the preparation method comprises: providing a substrate, placing the substrate in a plasma reaction chamber, passing the vapor of the monomer α into a plasma reactor, plasma discharge, and plasma polymerization on the surface of the substrate to form the pH responsive coating.

[0027] In some embodiments, the plasma discharge is a pulse discharge, the pulse power is 10W to 400W, the pulse duty cycle is 0.1% to 90%, the discharge time of the pulse output is 200s to 36000s, and the average power of the pulse is 10W to 50W.

[0028] The embodiments of the present disclosure also provide a product, at least a portion of the surface of the product having any of the above pH-responsive coatings.

[0029] Compared with the prior art, the technical solution of the embodiment of the present disclosure has the following beneficial effects:

[0030] The pH responsive coating of the embodiment of the present disclosure is a plasma polymerization coating formed by monomer α on at least a portion of the surface of a substrate. The structure of monomer α includes a carbon-carbon double bond structure and a weakly alkaline structure containing a nitrogen atom. The nitrogen atom in the weakly alkaline structure containing a nitrogen atom is located on a ring or connected to two secondary carbon atoms. The pH responsive coating has good pH responsiveness and exhibits different properties under acidic and alkaline environments. The pH responsive coating is hydrophobic under neutral and alkaline conditions, and the hydrophilic property of the pH responsive coating is improved under acidic conditions. DETAILED DESCRIPTION

[0031] Embodiments of the present disclosure are described in detail below. The embodiments are exemplary and are only used to explain the present disclosure, but should not be construed as limiting the present disclosure.

[0032] The inventors have found that by using a monomer comprising a carbon-carbon double bond structure and a structure comprising a nitrogen atom with a weak alkalinity to form a coating through PECVD, wherein the nitrogen atom in the structure comprising a nitrogen atom with a weak alkalinity in the monomer is located on a ring or connected to two secondary carbon atoms, the prepared coating has good pH responsiveness and has different hydrophilic and hydrophobic properties in acidic and alkaline environments.

[0033] The specific embodiment of the present disclosure provides a pH responsive coating, wherein the pH responsive coating is a plasma polymerized coating formed by monomer α on at least a portion of the surface of a substrate, wherein the monomer α has a structure shown in formula (1),

[0034]

[0035] In formula (1), L is a connecting structure, R1 and R2 are independently selected from C1-C 10 An organic group or a hydrogen atom, R3 is selected from C1-C 10 An alkyl group or a hydrogen atom, T is selected from the structure represented by formula (2), formula (3), or formula (4),

[0036]

[0037] In formula (2), R4, R5, R6, and R7 are independently selected from C1-C 10 Alkyl; in formula (3), A is a cyclic structure; in formula (4), B is a cyclic structure.

[0038] In the specific embodiment of the pH responsive coating disclosed herein, in order to make the coating have a better response to acidic and alkaline environments, the nitrogen atom in monomer α is connected to two secondary carbon atoms, that is, T is selected from the structure shown in formula (2), or the nitrogen atom in monomer α is located on the ring, that is, T is selected from the structure shown in formula (3) or formula (4). The pH responsive coating formed by the plasma of monomer α, the structure shown by T is located on the surface of the pH responsive coating, is easily protonated in an acidic environment, and is deprotonated in a neutral or alkaline environment, so that the pH responsive coating exhibits hydrophobicity in neutral and alkaline environments, and improves hydrophilicity in an acidic environment.

[0039] In some embodiments, the C1-C 10 The organic group is selected from C1-C 10 Alkyl or C1-C 10 Alkoxy acyl; In some embodiments, the C1-C 10 The organic group is selected from a C1-C4 alkyl group or a C1-C4 alkoxyacyl group.

[0040] In some specific embodiments, in formula (1), L is selected from C1-C4 alkylene, the structure shown in formula (5), or a connecting bond,

[0041]

[0042] In formula (5), R8 is selected from C1-C6 alkylene.

[0043] In some specific embodiments, the R1, R2, and R3 are independently selected from C1-C4 alkyl groups or hydrogen atoms, for example, they can be independently selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl or hydrogen atoms; the T is selected from the structure shown in formula (2), in which R4, R5, R6, and R7 are independently selected from methyl, ethyl, or propyl groups; the L is selected from the structure shown in formula (5), in which R8 is selected from methylene, ethylene or propylene.

[0044] In some specific embodiments, the R1, R2, and R3 are independently selected from a methyl group or a hydrogen atom, for example, they can be independently selected from a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group or a hydrogen atom; the T is selected from the structure shown in formula (2), in which R4, R5, R6, and R7 are independently selected from a methyl group or an ethyl group; the L is selected from the structure shown in formula (5), in which R8 is selected from a methylene group, an ethylene group or a propylene group.

[0045] In some specific embodiments, R1 and R2 are selected from hydrogen atoms, and R3 is selected from methyl or hydrogen atoms; L is selected from the structure shown in formula (5), in which R8 is selected from methylene or ethylene; T is selected from the structure shown in formula (2), in which R4, R5, R6, and R7 are selected from methyl.

[0046] In the pH responsive coating of the specific embodiments of the present disclosure, in some specific embodiments, the T is selected from the structure shown in formula (3) or formula (4), and in formula (3) and formula (4), the cyclic structures in formula (3) and formula (4) are independently selected from a five-membered ring or a six-membered ring.

[0047] In some specific embodiments, the five-membered ring or six-membered ring is selected from the structures shown in formula (6) to formula (12),

[0048]

[0049] In formula (6), n is an integer of 1 to 2, and n R9 are independently selected from C1-C4 alkyl groups or hydrogen atoms. Specifically, they can be independently selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl or hydrogen atoms.

[0050] In formula (7), m is an integer from 1 to 3, and m R 10 They are independently selected from C1-C4 alkyl groups or hydrogen atoms, and specifically, for example, they are independently selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl or hydrogen atoms.

[0051] In formula (8), a is an integer from 1 to 4, and a R 11 They are independently selected from C1-C4 alkyl groups or hydrogen atoms in formula (8), and specifically, for example, they are independently selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl or hydrogen atoms.

[0052] In formula (9), b is an integer from 1 to 3, and b R 12 They are independently selected from C1-C4 alkyl groups or hydrogen atoms, and specifically, for example, they are independently selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl or hydrogen atoms.

[0053] In formula (10), c is an integer from 1 to 3, and c R 13 They are independently selected from C1-C4 alkyl groups or hydrogen atoms, and specifically, for example, they are independently selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl or hydrogen atoms.

[0054] In formula (11), d is an integer from 1 to 4, and d R 14They are independently selected from C1-C4 alkyl groups or hydrogen atoms, and specifically, for example, they are independently selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl or hydrogen atoms.

[0055] In formula (12), e is an integer from 1 to 3, and e R 15 They are independently selected from C1-C4 alkyl groups or hydrogen atoms, and specifically, for example, they are independently selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl or hydrogen atoms.

[0056] In some specific embodiments, the L is connected to the ortho, meta or para position of the nitrogen atom in the cyclic structure represented by Formula (6) to Formula (12).

[0057] In some specific embodiments, the L is selected from a connecting bond or a structure shown in formula (5), wherein R8 is selected from methylene, ethylene or propylene.

[0058] In some specific embodiments, the L is selected from a connecting bond, and the R1, R2, and R3 are independently selected from a methyl group or a hydrogen atom.

[0059] In some specific embodiments, the T is selected from the six-membered ring structure shown in formula (8), wherein a is 1, and the R 11 is a hydrogen atom; said L is selected from a connecting bond; in formula (1), said R1, R2, and R3 are selected from hydrogen atoms. In some specific embodiments, the structure of formula (1) is connected to the ortho, meta, or para position of the nitrogen atom on the pyridine ring structure shown in formula (8).

[0060] In some specific embodiments, the L is selected from a connecting bond, the R1 is selected from a C1-C4 alkyl group or a hydrogen atom, the R2 is selected from a C1-C4 alkoxy acyl group, and the R3 is selected from a C1-C4 alkyl group or a hydrogen atom.

[0061] In some specific embodiments, the L is selected from a connecting bond, the R1 is selected from a methyl group or a hydrogen atom, the R2 is selected from a methoxyformyl group or an ethoxyformyl group, and the R3 is selected from a methyl group or a hydrogen atom.

[0062] In some specific embodiments, the T is selected from the six-membered ring structure shown in formula (8), wherein a is 1, and the R 11 is a hydrogen atom; said L is selected from a connecting bond; in formula (1), said R1 is selected from a hydrogen atom, said R2 is selected from a methoxyformyl group or an ethoxyformyl group, and said R3 is selected from a hydrogen atom. In some specific embodiments, the structure of formula (1) is connected to the ortho position, meta position or para position of the nitrogen atom on the pyridine ring structure shown in formula (8).

[0063] In some specific embodiments, the cyclic structure in formula (3) and formula (4) may be a polycyclic structure, such as a condensed ring structure or a bridged ring structure.

[0064] In the pH responsive coating of the specific embodiments of the present disclosure, in some specific embodiments, the monomer α includes: one or more of 2-(diisopropylamino)ethyl acrylate, 2-(diisopropylamino)ethyl methacrylate, 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, 3-(pyridin-3-yl)ethyl acrylate, and 3-(4-pyridinyl)methyl acrylate.

[0065] The pH responsive coating of the specific embodiment of the present disclosure shows different hydrophilicity and hydrophobicity in acidic and alkaline environments. In some specific embodiments, the pH responsive coating is hydrophobic in neutral or alkaline environments, and the hydrophilicity is improved in acidic environments. In some specific embodiments, the contact angle of the aqueous solution with a pH of 8.5 to 9.5 on the pH responsive coating is above 85°, and further above 90°; the contact angle of the aqueous solution with a pH of 6.5 to 7.5 on the pH responsive coating is above 85°, and further above 90°, and the pH responsive coating is hydrophobic in neutral and alkaline environments; the contact angle of the aqueous solution with a pH of 3.5 to 5 on the pH responsive coating is below 85°, and further, below 75°, or below 50°, or below 30°, or below 10°, and the hydrophilicity of the pH responsive coating is improved in acidic environments.

[0066] In the specific embodiments of the pH responsive coating disclosed herein, in some specific embodiments, the substrate forming the pH responsive coating includes: silicon, glass, PET, fabric, filter paper, etc.; in some specific embodiments, the pH responsive coating is formed on a substrate with a rough surface, such as fabric or filter paper. Since the surface has a certain roughness, the surface wettability is increased. Compared with the pH responsive coating formed on a smooth surface, the pH responsive coating formed on the substrate with a rough surface has better hydrophobicity under alkaline and neutral conditions, and the hydrophilic performance is improved under acidic conditions. In some specific embodiments, the pH responsive coating formed on the substrate with a rough surface exhibits superhydrophilicity under acidic conditions and exhibits superhydrophobicity under alkaline and neutral conditions.

[0067] In some specific embodiments, the pH responsive coating is formed on a fabric or filter paper, and the contact angle of an aqueous solution with a pH of 3.5 to 5 on the pH responsive coating is below 5°, for example, 0°, 1°, 2°, 3°, 4° or 5°, etc.; the contact angle of an aqueous solution with a pH of 6.5 to 7.5 on the pH responsive coating is above 130°, for example, 130°, 131°, 132°, 133°, 134°, 135°, 136°, 137°, 138° or 139°, etc., and further, above 140°, for example, 140°, 141°, 142°, etc. °, 143°, 144°, 145°, 146°, 147°, 148°, 149° or 150°, etc.; the contact angle of an aqueous solution with a pH value of 8.5 to 9.5 on the pH responsive coating is above 130°, for example, it can be 130°, 131°, 132°, 133°, 134°, 135°, 136°, 137°, 138° or 139°, etc., further, it is above 140°, for example, it can be 140°, 141°, 142°, 143°, 144°, 145°, 146°, 147°, 148°, 149° or 150°, etc.

[0068] The pH-responsive coating of the specific embodiment of the present disclosure has good response performance to pH. When the environmental pH changes, the chain structure, solubility, volume, wettability and other properties of the coating that are affected by the structure of the polymer constituting the coating will change. Therefore, in addition to the pH response in hydrophilic and hydrophobic environments, it can also be applied to multiple scenarios. In some specific embodiments, the pH-responsive coating can achieve precise release of drugs, can be used to develop highly sensitive biosensors, and can achieve self-repair under specific pH conditions.

[0069] The specific embodiments of the present disclosure also provide a method for preparing a pH responsive coating, which is used to prepare the pH responsive coating of any of the above specific embodiments, and the preparation method comprises: providing a substrate, placing the substrate in a plasma reaction chamber, passing the vapor of the monomer α into a plasma reactor, plasma discharge, and plasma polymerization on the surface of the substrate to form the pH responsive coating.

[0070] In the preparation method of the pH responsive coating of the specific embodiment of the present disclosure, in some specific embodiments, in the coating stage of introducing the monomer α for coating, the plasma discharge is a pulse discharge, and the average power of the pulse is controlled by controlling the pulse power and the pulse duty cycle to prepare a coating with good pH responsiveness. In some specific embodiments, the pulse power is 10W to 400W, and specifically, for example, it can be 10W, 20W, 30W, 40W, 50W, 60W, 70W, 80W, 90W, 100W, 120W, 140W, 160W, 180W, 200W, 220W, 240W, 260W, 280W, 300W, 320W, 340W, 360W, 380W or 400W, etc.; the pulse duty cycle is 0.1% to 90%, and specifically, for example, it can be 0.1%, 5%, 10%, 15%, 2 0%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85% or 90% and the like; pulse frequency 10-500Hz, for example, it can be 10Hz, 20Hz, 25Hz, 30Hz, 35Hz, 40Hz, 45Hz, 50Hz, 55Hz, 60Hz, 70Hz, 80Hz, 90Hz, 100Hz, 150Hz, 200Hz, 250Hz, 300Hz, 400Hz or 500Hz and the like.

[0071] The average power of a pulse discharge is defined as the pulse power multiplied by the pulse duty cycle. In some specific embodiments, the average power of the pulse is 10W to 110W, for example, 10W, 20W, 30W, 40W, 50W, 60W, 69W, 80W, 87W, 95W, 100W, 105W or 110W, etc. In order to reduce the risk of discharge destruction of weakly basic groups containing nitrogen atoms in the coating due to excessive plasma energy caused by excessive power, the average power is controlled to prepare a coating with good pH responsiveness. In some embodiments, the average power of the pulse is 10W to 50W, for example, it can be 10W, 15W, 20W, 24W, 27W, 30W, 33W, 36W, 40W, 43W, 46W or 50W, etc.; in some embodiments, the average power of the pulse is 10W to 30W, for example, it can be 10W, 11W, 12W, 13W, 14W, 15W, 16W, 17W, 18W, 19W, 20W, 21W, 22W, 23W, 24W, 25W, 26W, 27W, 28W, 29W or 30W, etc.

[0072] In some specific embodiments, the pulse discharge time is 200 to 36000 s, for example, it can be 200s, 300s, 400s, 500s, 600s, 800s, 1000s, 1200s, 1500s, 1800s, 2000s, 3000s, 5000s, 10000s, 15000s, 20000s, 25000s, 30000s or 36000s, etc.

[0073] In the preparation method of the pH responsive coating of the specific embodiment of the present disclosure, in some specific embodiments, during the coating stage of introducing monomer α for coating, the plasma discharge is continuous discharge, and the discharge power is controlled to prepare a coating with good pH responsiveness. In some specific embodiments, the discharge power is 10 to 300 W, and specifically can be 10 W, 20 W, 30 W, 40 W, 50 W, 60 W, 70 W, 80 W, 90 W, 100 W, 120 W, 140 W, 160 W, 180 W, 190 W, 200 W, 210 W, 220 W, 230 W, 240 W, 250 W, 260 W, 270 W, 280 W, 290 W, 300 W, 310 W, 320 W, 330 W, 340 W, 350 W, 360 W, 370 W, 380 W, 390 W, 400 W, 410 W, 420 W, 430 W, 440 W, 450 W, 460 W, 470 W, 480 W, 490 W, 500 W, 510 W, 520 W, 530 W, 540 W, 550 W, 560 W, 570 W, 580 W, 590 W, 600 W, 610 W, 620 W, 630 W, 640 W, 650 W, 660 W, 670 W, 680 W, 690 W, 700 W, 710 W, 720 W, 730 W, 740 W, 750 W, 760 W, 770 W 80W, 290W or 300W, etc.; discharge time 60 to 36000s, for example, it can be 60s, 100s, 200s, 300s, 400s, 500s, 600s, 1000s, 2000s, 3000s, 5000s, 10000s, 15000s, 20000s, 25000s, 30000s or 36000s, etc.

[0074] The preparation method of the pH responsive coating of the specific embodiment of the present disclosure, in order to further improve the bonding strength between the pH responsive coating and the substrate, in some specific embodiments, before the monomer α is introduced for coating, the substrate is pretreated with plasma. The specific method of pretreatment is, for example, evacuating to 10-200 mTorr, and introducing one or more mixed gases of He, Ar, O2, starting plasma discharge to pretreat the substrate, or using heat, oxygen or high-energy radiation to pretreat.

[0075] In the preparation method of the pH responsive coating of the specific embodiment of the present invention, continuous discharge or pulse discharge can be used in the pretreatment stage. In some specific embodiments, in the pretreatment stage, continuous discharge is used, and the discharge power is 50 to 600 W, and specific examples include 50 W, 100 W, 120 W, 140 W, 160 W, 180 W, 190 W, 200 W, 210 W, 220 W, 230 W, 240 W, 250 W, 260 W, 270 W, 280 W, 290 W, 300 W, 400 W, 500 W or 600 W, etc.; the discharge time is 60 to 2400 s, and specific examples include 60 s, 100 s, 200 s, 300 s, 400 s, 500 s, 600 s, 1000 s, 1200 s, 1500 s, 1800 s or 2400 s, etc. In some specific embodiments, in the pretreatment stage, pulse discharge is used, and the pulse duty cycle is 0.1% to 90%, and specific examples include 0.1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85% or 90% and the like; the pulse frequency is 10 to 500 Hz, and specific examples include 10 Hz, 20 Hz, 25 Hz, 30 Hz, 35 Hz, 40 Hz, 45 Hz, 50 Hz, 55 Hz, 60 Hz, 70 Hz, 80 Hz, 90 Hz, 100 Hz, 200 Hz, 300 Hz, 400 Hz or 500 Hz and the like. ; The discharge power is 10-500W, for example, it can be 10W, 20W, 30W, 40W, 50W, 60W, 70W, 80W, 90W, 100W, 120W, 140W, 160W, 180W, 190W, 200W, 210W, 220W, 230W, 240W, 250W, 260W, 270W, 280W, 290W, 300W, 400W, 500W, etc.; The discharge time is 60-2400s, for example, it can be 60s, 100s, 200s, 300s, 400s, 500s, 600s, 1000s, 1200s, 1500s, 1800s or 2400s, etc.

[0076] In the preparation method of the pH responsive coating of the specific embodiment of the present disclosure, in some specific embodiments, the plasma discharge mode can be various existing discharge modes, for example, electrodeless discharge (such as radio frequency inductively coupled discharge, microwave discharge), single electrode discharge (such as corona discharge, plasma jet formed by monopolar discharge), double electrode discharge (such as dielectric barrier discharge, bare electrode radio frequency glow discharge) and multi-electrode discharge (such as discharge using a floating electrode as the third electrode).

[0077] In the preparation method of the pH responsive coating according to the specific embodiment of the present invention, in some specific embodiments, the flow rate of the monomer α is 10-2000 μL / min, for example, it can be 50 μL / min, 100 μL / min, 120 μL / min, 150 μL / min, 160 μL / min, 200 μL / min, 300 μL / min, 400 μL / min, 500 μL / min, 1000 μL / min, 1500 μL / min or 2000 μL / min, etc.; the temperature of the plasma reaction chamber is controlled at 30°C to 60°C, for example, it can be 30°C, 40°C, 45°C, 50°C, 55°C or 60°C, etc.

[0078] In the preparation method of the pH responsive coating of the specific embodiment of the present disclosure, in some specific embodiments, the preparation method further includes post-processing, and the post-processing includes: after the preparation of the pH responsive coating on the surface of the substrate is completed, clean compressed air or inert gas is introduced until the plasma reaction chamber is restored to normal pressure, the plasma reaction chamber is opened, and the substrate is taken out. In some specific embodiments, the inert gas is introduced, and the flow rate of the inert gas is 5 to 300 sccm.

[0079] The present disclosure also provides a product, wherein at least part of the surface of the product has a pH responsive coating of any of the above embodiments, thereby giving at least part of the surface of the product good pH responsive performance. In some embodiments, the surface of the product formed with a pH responsive coating is hydrophobic in alkaline and neutral environments, and the hydrophilic performance is improved in acidic environments. In some embodiments, the product is a pH responsive microfluidic device.

[0080] The present disclosure is further described below through specific embodiments.

[0081] Example

[0082] Test Method Description

[0083] Coating thickness: Use American Filmetrics F20-UV-film thickness measuring instrument for detection.

[0084] Coating contact angle: tested according to GB / T 30447-2013 standard.

[0085] Example 1

[0086] The substrate Si wafer, glass, PET sheet, fabric, and filter paper were placed on the substrate placement bracket of the plasma reaction chamber, and the chamber was evacuated to 100 mTorr, and helium was introduced at a flow rate of 100 sccm. The chamber temperature was 50°C.

[0087] The chamber pressure was maintained at 100 mTorr, the helium flow rate was maintained at 100 sccm, and the plasma continuous discharge was started with a discharge power of 300 W and a continuous discharge of 600 s to pretreat the substrate;

[0088] Then, the monomer 2-(diisopropylamino)ethyl acrylate was introduced into the evaporator at a flow rate of 120 μL / min, and then introduced into the plasma reaction chamber after being vaporized at a vaporization temperature of 120° C., the chamber pressure was maintained at 100 mTorr, the helium flow rate was maintained at 100 sccm, the radio frequency plasma discharge was turned on, the radio frequency energy output mode was pulsed, and plasma chemical vapor deposition was performed on the surface of the substrate, wherein the pulse duty cycle was 30%, the pulse frequency was 250 Hz, the pulse discharge power was 80 W, the average power was 24 W, and the reaction time was 1200 s;

[0089] After the coating is completed, the chamber is filled with compressed air to restore the normal pressure, and the coated substrate is taken out. The coating thickness, acidic aqueous solution contact angle, neutral aqueous solution contact angle, and alkaline aqueous solution contact angle on the Si wafer are tested, and the test results are listed in Table 1 below; the acidic aqueous solution (artificial sweat with a pH of 4) contact angle, neutral aqueous solution (water with a pH of 7) contact angle, and alkaline aqueous solution (artificial sweat with a pH of 9) contact angle of the coating on the Si wafer, glass, PET sheet, fabric, and filter paper are tested respectively, and the test results are listed in Table 2 below; the Si wafer is subjected to a cyclic test of the acidic aqueous solution contact angle and the alkaline aqueous solution contact angle, and the test is performed 5 times, and the test results are listed in Table 3 below.

[0090] Example 2

[0091] The substrate Si wafer was placed on the substrate placement support of the plasma reaction chamber, the chamber was evacuated to 80 mTorr, helium was introduced at a flow rate of 80 sccm, and the chamber temperature was 50°C;

[0092] The chamber pressure was maintained at 80 mTorr, the helium flow rate was maintained at 80 sccm, and the plasma continuous discharge was started with a discharge power of 200 W and the discharge lasted for 300 s to pretreat the substrate;

[0093] Then, the monomer 2-vinylpyridine was introduced into the evaporator at a flow rate of 100 μL / min, and then introduced into the plasma reaction chamber after being vaporized at a vaporization temperature of 120° C., the chamber pressure was maintained at 80 mTorr, the helium flow rate was maintained at 80 sccm, the radio frequency plasma discharge was turned on, the radio frequency energy output mode was pulsed, and plasma chemical vapor deposition was performed on the surface of the substrate, wherein the pulse duty ratio was 60%, the pulse frequency was 200 Hz, the pulse discharge power was 50 W, the average power was 30 W, and the reaction time was 1200 s;

[0094] After the coating is completed, compressed air is filled to restore the chamber to normal pressure, and the coated substrate is taken out to test the coating thickness on the Si wafer, the contact angle of the acidic aqueous solution (artificial sweat with a pH of 4), the contact angle of the neutral aqueous solution (water with a pH of 7), and the contact angle of the alkaline aqueous solution (artificial sweat with a pH of 9). The test results are listed in Table 1 below.

[0095] Example 3

[0096] The substrate Si wafer was placed on the substrate placement support of the plasma reaction chamber, the chamber was evacuated to 100 mTorr, helium was introduced at a flow rate of 100 sccm, and the chamber temperature was 50°C;

[0097] The chamber pressure was maintained at 100 mTorr, the helium flow rate was maintained at 100 sccm, and the plasma continuous discharge was started with a discharge power of 300 W and a continuous discharge of 600 s to pretreat the substrate;

[0098] Then, the monomer 2-(diisopropylamino)ethyl acrylate was introduced into the evaporator at a flow rate of 120 μL / min, and then introduced into the plasma reaction chamber after being vaporized at a vaporization temperature of 120° C., the chamber pressure was maintained at 100 mTorr, the helium flow rate was maintained at 100 sccm, the radio frequency plasma discharge was turned on, the radio frequency energy output mode was pulsed, and plasma chemical vapor deposition was performed on the surface of the substrate, wherein the pulse duty cycle was 30%, the pulse frequency was 250 Hz, the pulse discharge power was 350 W, the average power was 105 W, and the reaction time was 1200 s;

[0099] After the coating is completed, compressed air is filled to restore the chamber to normal pressure, and the coated substrate is taken out to test the coating thickness on the Si wafer, the contact angle of the acidic aqueous solution (artificial sweat with a pH of 4), the contact angle of the neutral aqueous solution (water with a pH of 7), and the contact angle of the alkaline aqueous solution (artificial sweat with a pH of 9). The test results are listed in Table 1 below.

[0100] Example 4

[0101] The substrate Si wafer was placed on the substrate placement support of the plasma reaction chamber, the chamber was evacuated to 100 mTorr, helium was introduced at a flow rate of 100 sccm, and the chamber temperature was 50°C;

[0102] The chamber pressure was maintained at 100 mTorr, the helium flow rate was maintained at 100 sccm, and the plasma continuous discharge was started with a discharge power of 300 W and a continuous discharge of 600 s to pretreat the substrate;

[0103] Then, the monomer 2-(diisopropylamino)ethyl acrylate was introduced into the evaporator at a flow rate of 120 μL / min, and then introduced into the plasma reaction chamber after being vaporized at a vaporization temperature of 120° C., the chamber pressure was maintained at 100 mTorr, the helium flow rate was maintained at 100 sccm, the radio frequency plasma discharge was turned on, the radio frequency energy output mode was pulsed, and plasma chemical vapor deposition was performed on the surface of the substrate, wherein the pulse duty cycle was 30%, the pulse frequency was 250 Hz, the pulse discharge power was 290 W, the average power was 87 W, and the reaction time was 1200 s;

[0104] After the coating is completed, compressed air is filled to restore the chamber to normal pressure, and the coated substrate is taken out to test the coating thickness on the Si wafer, the contact angle of the acidic aqueous solution (artificial sweat with a pH of 4), the contact angle of the neutral aqueous solution (water with a pH of 7), and the contact angle of the alkaline aqueous solution (artificial sweat with a pH of 9). The test results are listed in Table 1 below.

[0105] Example 5

[0106] The substrate Si wafer was placed on the substrate placement support of the plasma reaction chamber, the chamber was evacuated to 100 mTorr, helium was introduced at a flow rate of 100 sccm, and the chamber temperature was 50°C;

[0107] The chamber pressure was maintained at 100 mTorr, the helium flow rate was maintained at 100 sccm, and the plasma continuous discharge was started with a discharge power of 300 W and a continuous discharge of 600 s to pretreat the substrate;

[0108] Then, the monomer 2-(diisopropylamino)ethyl acrylate was introduced into the evaporator at a flow rate of 120 μL / min, and then introduced into the plasma reaction chamber after being vaporized at a vaporization temperature of 120° C., the chamber pressure was maintained at 100 mTorr, the helium flow rate was maintained at 100 sccm, and the radio frequency plasma discharge was turned on. The radio frequency energy output mode was pulsed, and plasma chemical vapor deposition was performed on the surface of the substrate, wherein the pulse duty cycle was 30%, the pulse frequency was 250 Hz, the pulse discharge power was 230 W, the average power was 69 W, and the reaction time was 1200 s;

[0109] After the coating is completed, compressed air is filled to restore the chamber to normal pressure, and the coated substrate is taken out to test the coating thickness on the Si wafer, the contact angle of the acidic aqueous solution (artificial sweat with a pH of 4), the contact angle of the neutral aqueous solution (water with a pH of 7), and the contact angle of the alkaline aqueous solution (artificial sweat with a pH of 9). The test results are listed in Table 1 below.

[0110] Comparative Example 1

[0111] The substrate Si wafer was placed on the substrate placement support of the plasma reaction chamber, the chamber was evacuated to 100 mTorr, helium was introduced at a flow rate of 100 sccm, and the chamber temperature was 50°C;

[0112] The chamber pressure was maintained at 100 mTorr, the helium flow rate was maintained at 100 sccm, and the plasma continuous discharge was started with a discharge power of 300 W and a continuous discharge of 600 s to pretreat the substrate;

[0113] Then, the monomer isooctyl acrylate is introduced into the evaporator at a flow rate of 120 μL / min, and then introduced into the plasma reaction chamber after being vaporized at a vaporization temperature of 120° C., the chamber pressure is maintained at 100 mTorr, the helium flow rate is maintained at 100 sccm, and the radio frequency plasma discharge is turned on. The radio frequency energy output mode is pulsed, and plasma chemical vapor deposition is performed on the surface of the substrate, wherein the pulse duty cycle is 30%, the pulse frequency is 250 Hz, the pulse discharge power is 80 W, the average power is 24 W, and the reaction time is 1200 s;

[0114] After the coating is completed, compressed air is filled to restore the chamber to normal pressure, and the coated substrate is taken out to test the coating thickness on the Si wafer, the contact angle of the acidic aqueous solution (artificial sweat with a pH of 4), the contact angle of the neutral aqueous solution (water with a pH of 7), and the contact angle of the alkaline aqueous solution (artificial sweat with a pH of 9). The test results are listed in Table 1 below.

[0115] Comparative Example 2

[0116] The substrate Si wafer was placed on the substrate placement support of the plasma reaction chamber, the chamber was evacuated to 80 mTorr, helium was introduced at a flow rate of 100 sccm, and the chamber temperature was 50°C;

[0117] The chamber pressure was maintained at 80 mTorr, the helium flow rate was maintained at 100 sccm, and the plasma continuous discharge was started with a discharge power of 200 W and a continuous discharge of 600 s to pretreat the substrate;

[0118] Then, the monomer dimethylaminoethyl methacrylate was introduced into the evaporator at a flow rate of 120 μL / min, and then introduced into the plasma reaction chamber after being vaporized at a vaporization temperature of 120° C., the chamber pressure was maintained at 80 mTorr, the helium flow rate was maintained at 100 sccm, and the radio frequency plasma discharge was turned on. The radio frequency energy output mode was pulsed, and plasma chemical vapor deposition was performed on the surface of the substrate, wherein the pulse duty cycle was 15%, the pulse frequency was 150 Hz, the pulse discharge power was 180 W, the average power was 27 W, and the reaction time was 1200 s;

[0119] After the coating is completed, compressed air is filled to restore the chamber to normal pressure, and the coated substrate is taken out to test the coating thickness on the Si wafer, the contact angle of the acidic aqueous solution (artificial sweat with a pH of 4), the contact angle of the neutral aqueous solution (water with a pH of 7), and the contact angle of the alkaline aqueous solution (artificial sweat with a pH of 9). The test results are listed in Table 1 below.

[0120] Table 1 Test results of coating thickness, contact angle of acidic aqueous solution, contact angle of neutral aqueous solution and contact angle of alkaline aqueous solution on substrate Si wafer

[0121]

[0122] According to the test results in Table 1, it can be seen from the monomers of Examples 1 to 5 that the monomers contain a structure in which a nitrogen atom is connected to two secondary carbon atoms (Example 1, Examples 3 to 5), or a compound having a weakly basic group such as a pyridine ring structure (Example 2), and the coating obtained has good pH responsiveness, is hydrophobic in neutral and alkaline environments, and has improved hydrophilic properties in acidic environments. There is no weakly basic group in the monomer structure used in Comparative Example 1, and the prepared coating does not have pH responsiveness, and is hydrophobic in both acidic and alkaline environments. The monomer used in Comparative Example 2 has a nitrogen atom connected to two methyl groups in the monomer structure, but not to a secondary carbon atom, and the prepared coating is hydrophilic in both acidic and alkaline environments, and has poor pH responsiveness.

[0123] According to the test results in Table 1, compared with Examples 3 to 5, the average power used to prepare the coating in Examples 1 to 2 is lower, which reduces the risk of high-energy plasma causing the weakly alkaline groups containing nitrogen atoms in the coating to be destroyed. The pH responsiveness of the prepared coating is relatively better, and the hydrophilic performance in an acidic environment is better.

[0124] Table 2 Test results of the contact angles of acidic aqueous solution, neutral aqueous solution and alkaline aqueous solution of the coating on different substrates in Example 1

[0125]

[0126] According to the test results in Table 2, the coatings prepared in Example 1 on different substrates have good pH responsiveness. For fabrics and filter papers with a certain degree of roughness, the coatings have better hydrophilicity in an acidic environment and better hydrophobicity in an alkaline environment.

[0127] Table 3 Cyclic test results of the contact angle of the acidic aqueous solution and the contact angle of the alkaline aqueous solution of the coating on the Si substrate in Example 1

[0128]

[0129] According to the test results in Table 3, the pH responsive coating prepared in Example 1 was subjected to 5 cycle tests using acidic and alkaline aqueous solutions, and the contact angle did not change significantly, indicating that the prepared pH responsive coating has repeatable reversibility in its response to the hydrophilicity and hydrophobicity caused by pH changes.

[0130] The above is only an exemplary embodiment used to illustrate the principle of the present disclosure, and is not intended to limit the scope of protection of the present disclosure. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also within the scope of protection of the present disclosure.

Claims

1. A pH responsive coating, characterized in that: The pH responsive coating is a plasma polymerized coating formed by monomer α on at least a portion of the surface of the substrate, wherein the monomer α has a structure shown in formula (1), In formula (1), L is a connecting structure, R1 and R2 are independently selected from C1-C 10 An organic group or a hydrogen atom, R3 is selected from C1-C 10 An alkyl group or a hydrogen atom, T is selected from the structure represented by formula (2), formula (3), or formula (4), In formula (2), R4, R5, R6, and R7 are independently selected from C1-C 10 alkyl; In formula (3), A is a cyclic structure; In formula (4), B is a cyclic structure.

2. The pH responsive coating according to claim 1, characterized in that C1-C 10 The organic group is selected from C1-C 10 Alkyl or C1-C 10 Alkoxy acyl.

3. The pH responsive coating according to claim 2, characterized in that The L is selected from a C1-C4 alkylene group, a structure shown in formula (5), or a connecting bond, In formula (5), R8 is selected from C1-C6 alkylene.

4. The pH responsive coating according to claim 3, characterized in that Said R1, R2, and R3 are independently selected from C1-C4 alkyl or hydrogen atom; The T is selected from the structure shown in formula (2), wherein R4, R5, R6, and R7 are independently selected from methyl, ethyl, or propyl; The L is selected from the structure shown in formula (5), in which R8 is selected from methylene, ethylene or propylene.

5. The pH responsive coating according to claim 4, characterized in that The R1, R2, and R3 are independently selected from a methyl group or a hydrogen atom, and the R4, R5, R6, and R7 are independently selected from a methyl group or an ethyl group.

6. The pH responsive coating according to claim 2, characterized in that The T is selected from the structure shown in formula (3) or formula (4), and in formula (3) and formula (4), the cyclic structure is a five-membered ring or a six-membered ring.

7. The pH responsive coating according to claim 6, characterized in that The five-membered ring or six-membered ring is selected from the structures shown in formula (6) to formula (12), In formula (6), n is an integer of 1 to 2, and n R9 are independently selected from C1-C4 alkyl groups or hydrogen atoms; In formula (7), m is an integer from 1 to 3, and m R 10 are independently selected from C1-C4 alkyl, or a hydrogen atom; In formula (8), a is an integer from 1 to 4, and a R 11 are independently selected from C1-C4 alkyl, or a hydrogen atom; In formula (9), b is an integer from 1 to 3, and b R 12 are independently selected from C1-C4 alkyl, or a hydrogen atom; In formula (10), c is an integer from 1 to 3, and c R 13 are independently selected from C1-C4 alkyl, or a hydrogen atom; In formula (11), d is an integer from 1 to 4, and d R 14 are independently selected from C1-C4 alkyl, or a hydrogen atom; In formula (12), e is an integer from 1 to 3, and e R 15 Each is independently selected from a C1-C4 alkyl group, or a hydrogen atom.

8. The pH responsive coating according to claim 7, characterized in that The L is selected from a connecting bond, and the R1, R2, and R3 are independently selected from a methyl group or a hydrogen atom.

9. The pH responsive coating according to claim 7, characterized in that: The L is selected from a connecting bond, the R1 is selected from a methyl group or a hydrogen atom, the R2 is selected from a methoxyformyl group or an ethoxyformyl group, and the R3 is selected from a methyl group or a hydrogen atom.

10. The pH responsive coating according to claim 1, characterized in that: The monomer α includes: one or more of 2-(diisopropylamino)ethyl acrylate, 2-(diisopropylamino)ethyl methacrylate, 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, 3-(pyridin-3-yl)ethyl acrylate, and 3-(4-pyridinyl)methyl acrylate.

11. The pH responsive coating according to any one of claims 1 to 10, characterized in that The contact angle of the aqueous solution with a pH value of 3.5 to 5 on the pH responsive coating is below 30°.

12. The pH responsive coating according to claim 11, characterized in that The contact angle of the aqueous solution with a pH value of 3.5 to 5 on the pH responsive coating is below 10°.

13. The pH responsive coating according to any one of claims 1 to 10, characterized in that The substrates include: silicon, glass, PET, fabric, and filter paper.

14. A method for preparing a pH responsive coating according to any one of claims 1 to 13, characterized in that: include: A substrate is provided, and the substrate is placed in a plasma reaction chamber. The steam of the monomer α is introduced into a plasma reactor, and plasma discharge is performed to form the pH responsive coating on the surface of the substrate through plasma polymerization.

15. The preparation method according to claim 14, characterized in that: The plasma discharge is a pulse discharge, the pulse power is 10W-400W, the pulse duty ratio is 0.1%-90%, the discharge time of the pulse output is 200s-36000s, and the average power of the pulse is 10W-50W.

16. A product, characterized in that At least part of the surface of the product has the pH responsive coating according to any one of claims 1 to 13.

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