Preparation method of antibacterial liquid-like super-smooth surface

Abstract

The invention belongs to the technical field of liquid-like surface preparation, and particularly relates to an electrodeposition preparation method of an antibacterial liquid-like super-smooth surface, which adopts an electrochemical bionic assembly strategy: taking a conductive substrate as a working electrode, and performing electrodeposition on the working electrode in an electrolyte containing metal nitrate, a functionalized lubricating liquid, a silane coupling agent and a carboxyl-containing bacteriostatic agent to obtain the antibacterial liquid-like super-smooth surface. Electrodeposition parameters are accurately regulated and controlled, and a composite functional film layer of'beaded 'chemical antifouling active sites is constructed on the surface of a conductive substrate in situ, so that the liquid-like surface has double functions of'physical antifouling' and'chemical antifouling ', and meanwhile, the film forming thickness and uniformity are improved; the technical bottlenecks that the thickness of a traditional liquid-like surface formed film is nanoscale, a single physical antifouling mechanism is adopted and the durability is insufficient are broken through, and a novel solution with long-acting stability and an active sterilization function is provided for the antifouling surface of maritime work equipment; the molecular structure is innovated through electrochemical interface engineering, the preparation process is simple, the cost is low, and the method is suitable for large-scale application.

Description

Technical Field:

[0001] The present invention belongs to the technical field of liquid-like surface preparation, and particularly relates to an electrodeposition preparation method of an antibacterial liquid-like super-slippery surface for preventing biofouling of marine equipment. Background Art:

[0002] The problem of biofouling suffered by offshore engineering equipment during underwater service increases the navigation resistance, raises the operation and maintenance costs, and poses safety hazards. In recent years, people have used superwetting surface technologies to treat the surfaces of offshore engineering equipment to achieve effects such as underwater anti-fouling and drag reduction. The most representative types of superwetting surfaces include: superhydrophobic surfaces, superamphiphobic surfaces, lubricant-infused slippery surfaces (SLIPS), and liquid-like surfaces. The service environment of offshore engineering equipment during underwater service has high hydrostatic pressure and continuous water flow scouring. Superhydrophobic / superamphiphobic surfaces that achieve superhydrophobic effects through a liquid-gas interface constructed by a micro-nano rough structure / a liquid-gas interface constructed by a multiple concave structure have poor underwater stability at the liquid-gas interface. SLIPS switches the liquid-gas interface to a liquid-liquid interface on the basis of a superhydrophobic surface, greatly improving the stability. However, since the lubricating liquid of SLIPS is only physically adsorbed by capillary action brought about by the rough structure, during long-term service, the lubricating liquid is prone to volatilization or being displaced by oil-based fouling substances. Based on this, McCarthy et al. (Angew. Chem. 2016, 55, 244-248) proposed a "liquid-like" surface (Liquid-like surface, LLS) with covalently bonded and immobilized lubricating liquid. The liquid-like surface uses highly flexible molecular chains with extremely low glass transition temperatures as "molecular brushes". The chemical bonds of the molecular chains have relatively low rotational conformational transition energy barriers, enabling them to rotate and move freely like a liquid under the premise of a room temperature environment and one end being fixed. In the existing technology, polymers with liquid-like properties mainly include polydimethylsiloxane (PDMS, Tg = -127 °C), polyethylene glycol (PEG, Tg = -70 °C), and perfluoropolyether (PTFE, Tg = -116 °C). However, on the one hand, the film formation of the liquid-like surface mainly relies on covalent bonding with functional groups on the substrate. Due to the limited number of substrate functional groups, the film formation driving force and film formation thickness are limited. The thickness of the liquid-like film layer is often only at the nanometer level, and the service durability is poor. On the other hand, the anti-fouling of the liquid-like surface mainly relies on its single physical anti-fouling mechanism similar to a fluid, and the molecular structure of the polymer chain segment itself does not contain chemical anti-fouling active sites with bactericidal effects. For example, the liquid-like surface disclosed in Chinese Patent 202411522332.6 is made of polydimethylsiloxane or perfluoropolyether, and the preparation method includes the condensation polymerization of siloxane monomers and the direct grafting of long-chain polymers. Among them, the method for preparing a liquid-like surface by the condensation polymerization of siloxane monomers includes: introducing active hydroxyl groups on the substrate surface by plasma treatment or piranha solution treatment; for siloxanes without halogenated groups, condensing them by solution polymerization under acid or base catalysis to form a liquid-like surface; for siloxanes with halogenated groups, adopting the method of solution polymerization under acid or base catalysis and constructing a liquid-like surface by chemical vapor deposition.The method of directly grafting long-chain polymers to prepare liquid-like surfaces includes: firstly introducing functional groups (carboxyl, epoxy, carbon-carbon double bonds) that can be used for long-chain polymer grafting on the substrate surface, and then grafting the long-chain polymer to the substrate surface under ultraviolet light or heating conditions to form a liquid-like surface. The problem of film thickness at the nanometer level and only physical antifouling greatly limits its application in underwater marine equipment and the improvement of antifouling effect.

[0003] Starting from the molecular structure of the liquid-like membrane system, in order to prevent the liquid-like molecular brush layer from "flipping and sinking" into the polymer resin chain due to high hydrostatic pressure and water flow impact, resulting in failure between "pores", the molecular chain can maintain a low rotational conformational transition energy barrier, and at the same time, the overall steric hindrance of the liquid-like molecular brush can be increased, so that the molecular brush is not easy to enter the pores. Think of the "pearl bracelet" made of rubber-like rubber flexible materials in daily life. After the pearl particles are "stringed" on the rubber band, it can still maintain a certain degree of softness. At the same time, the volume of the pearl bracelet is significantly larger than the rubber band. If nanomaterials (NPs) with bactericidal activity can be grown in situ on the molecular chain links of the liquid-like molecular brush similar to "stringing beads" to form a bead chain topology, the steric hindrance of the liquid-like molecular brush can be increased at the molecular level, so that it is not easy to fail due to "flipping and sinking" into the resin pores. At the same time, it can also have the function of "chemical antifouling", "killing two birds with one stone".

[0004] Because the metal substrates such as titanium alloys used in marine engineering equipment serving underwater have conductive properties, if the conductive properties of the substrate material itself can be utilized, the electrochemical-assisted method can be used to achieve the in-situ growth of nanomaterials with bactericidal activity on liquid-like polymer brush chains. This is simple, easy, low-cost, and has greater application potential. There is no report in the prior art that directly applies electrochemical methods to molecular brushes on liquid-like surfaces to grow chemical antifouling active sites using a "beads-on-a-string" strategy to prepare marine antifouling liquid-like surfaces with both chemical and physical antifouling functions. Therefore, a method for preparing an antibacterial liquid-like super-slippery surface is developed and designed. Based on the electrochemical "beads-on-a-string" strategy, a "beads-on-a-string" nano-active site composite film layer is constructed in situ by electrodeposition to upgrade the function of the liquid-like surface, effectively solving the problem of limited film thickness and single antifouling function of the liquid-like surface, and providing a new method and idea for the upgrading of super-wetting surface treatment technology for marine engineering equipment serving underwater. Summary of the invention:

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art, develop and design a method for preparing an antibacterial liquid-like ultra-smooth surface, and construct a "beaded" nano-active site composite film layer in situ through electrodeposition to functionalize the liquid-like surface.

[0006] To achieve the above object, a method for preparing an antibacterial liquid-like super-slippery surface according to the present invention in-situ "strings beads" on a liquid-like polymer molecular brush by an electrochemical method to construct anti-fouling nano-active sites with a beaded-chain topological structure, and prepare an antibacterial liquid-like functionalized super-wettable surface with multiple marine anti-fouling mechanisms. The specific process includes the following steps:

[0007] I. Prepare the electrodeposition solution

[0008] In a mixed solvent composed of water and ethanol with a volume ratio of 4:1 - 1:4, add 0.5 - 3 g / L of metal nitrate, 1 - 10 g / L of functionalized lubricant, 0.1 - 1 g / L of silane coupling agent (KH560), 0.1 - 5 g / L of cetyltrimethylammonium bromide (CTAB), and 0.1 - 5 g / L of carboxyl-containing bacteriostatic agent, stir and dissolve them evenly to obtain the electrodeposition solution;

[0009] The metal nitrate includes one or more of zinc nitrate, cobalt nitrate, and copper nitrate;

[0010] The functionalized lubricant includes one or more of aqueous amino silicone oil, aqueous mercapto silicone oil, and aqueous fluorinated lubricating oil;

[0011] The carboxyl-containing bacteriostatic agent includes one or more of trimesic acid, terephthalic acid, and penicillamine;

[0012] II. Electrodeposition

[0013] Add the electrodeposition solution into an electrolytic cell, stir it evenly by ultrasonic wave, use a saturated calomel electrode as the reference electrode, a conductive substrate as the working electrode, and a platinum mesh / platinum sheet as the counter electrode, and perform electrodeposition at a set deposition potential, deposition time, and deposition temperature to obtain a liquid-like film layer;

[0014] Among them, the conductive substrate includes conductive glass or metal devices;

[0015] The deposition potential is -0.9 V to -1.8 V, the deposition time is 30 s to 20 min, and the deposition temperature is 20 °C to 50 °C;

[0016] III. Curing

[0017] Cure the liquid-like film layer at a set temperature and time;

[0018] Among them, the curing temperature is 20 °C to 150 °C, and the curing time is 0.5 h to 5 h.

[0019] Compared with the prior art, the present invention adopts an electrochemical bionic assembly strategy: taking a conductive substrate as a working electrode, precisely controlling the electrodeposition parameters in an electrolyte containing metal nitrate, functionalized lubricant, silane coupling agent and carboxyl-containing bacteriostatic agent, and in-situ constructing a composite functionalized film layer with "bead-like" chemical antifouling active sites on the surface of the conductive substrate, endowing the liquid-like surface with dual functions of "physical antifouling" and "chemical antifouling". Meanwhile, the film thickness and uniformity are improved, breaking through the technical bottlenecks of the nanoscale film thickness, single physical antifouling mechanism and insufficient durability of the traditional liquid-like surface, providing a new solution with long-term stability and active bactericidal function for the antifouling surface of marine engineering equipment; it realizes the innovation of molecular structure through electrochemical interface engineering, and has simple preparation process, low cost and is suitable for large-scale application. Brief Description of the Drawings:

[0020] Figure 1 It is a schematic diagram of the preparation process flow of the present invention.

[0021] Figure 2 It is the shape comparison result of Ti / eLLS@eNPs and Ti / eLLS related to Example 1 of the present invention. Among them, a is a schematic diagram of the change of the film rolling angle with the deposition potential, b is a schematic diagram of the change of the thickness with the deposition potential, c is a schematic diagram of the change of the rolling angle after soaking in static seawater at normal temperature and pressure for 1 month, d is the pH-responsive release diagram of the bactericide trimesic acid in Ti / eLLS@eNPs, e is the SEM morphology diagram of Ti / eLLS@eNPs, f is the comparison diagram of the antibacterial rate of Escherichia coli, and g is the comparison diagram of the antibacterial amount of Escherichia coli. Detailed Description of the Invention:

[0022] The present invention will be further described below through examples in combination with the drawings.

[0023] Example 1:

[0024] The technological process of the preparation method of the antibacterial liquid-like super-slippery surface involved in this example is as follows:

[0025] 5 g / L of aqueous amino silicone oil (aqueous amino-terminated polydimethylsiloxane) is functionalized with 0.5 g / L of KH560 as the raw material for constructing the liquid-like polymer molecular brush. Ethanol and water with a volume ratio of 4:1 are used as the solvent, 1 g / L of zinc nitrate is used as the supporting electrolyte, 1 g / L of trimesic acid is used as the antibacterial active substance, and 0.5 g / L of CTAB is used as the auxiliary deposition surfactant to prepare an electrodeposition solution; through a three-electrode system (saturated calomel electrode as the reference electrode), at a temperature of 25 °C, deposit on TC4 type titanium alloy for 200 s between -0.8 V and -1.6 V, and use cathodic electrodeposition local alkalization to promote the deprotonation of trimesic acid and Zn in the zinc nitrate supporting electrolyte 2+Coordination, in-situ growth of antibacterial and antifouling active nanomaterial sites (eNPs) on the polymer molecular brush chain segments, and curing at 30 °C for 5 hours to obtain functionalized liquid-like surfaces (Ti / eLLS@eNPs) with "beaded" antibacterial active sites at different deposition potentials.

[0026] The properties of the functionalized liquid-like surfaces (Ti / eLLS@eNPs) with "beaded" antibacterial active sites at different deposition potentials prepared in this example and the liquid-like surfaces (Ti / eLLS) prepared under the same conditions are compared as follows:

[0027] From the schematic diagram of the change of the film rolling angle with the deposition potential, it can be seen that the rolling angle decreases significantly from 23° when no voltage is applied (represented by 0 V) to below 10°. The rolling angles of Ti / eLLS and Ti / eLLS@eNPs are similar, indicating that the "beaded" strategy has little effect on the wettability of the liquid-like surface.

[0028] From the schematic diagram of the change of the thickness with the deposition potential, it can be seen that the electrochemical-assisted technology can increase the thickness from the nanoscale (0 V, 565 nm) to 4 μm, indicating that electrodeposition has the effects of both thickening and enhancing the film-forming driving force.

[0029] From the schematic diagram of the change of the rolling angle after soaking in static seawater at normal temperature and pressure for 1 month, it can be seen that after soaking in seawater for up to 30 days, the rolling angle of Ti / eLLS@eNPs has been maintained within 10°, greatly improving the durability.

[0030] From the pH-responsive release diagram of the bactericide trimesic acid in Ti / eLLS@eNPs, it can be seen that the trimesic acid (BTC) grown after "beading" has pH-responsive release characteristics.

[0031] From the SEM morphology diagram of Ti / eLLS@eNPs, it can be seen that Ti / eLLS@eNPs shows the characteristics of overall cross-linking with a few pores.

[0032] From the comparison diagram of the antibacterial rate and antibacterial amount of Escherichia coli, it can be seen that the antibacterial rate of Escherichia coli after "beading" has increased from 35.13% to 99.89%, indicating that the "beaded" strategy can effectively improve the antibacterial and chemical antifouling effects.

[0033] Example 2:

[0034] The technological process of the preparation method of the antibacterial liquid-like super-slippery surface involved in this example is as follows:

[0035] 4 g / L of aqueous mercapto silicone oil (aqueous mercapto-terminated polydimethylsiloxane) was functionalized with 0.4 g / L of KH560 at the end group and used as the raw material for constructing the liquid-like polymer molecular brush. Ethanol and water with a volume ratio of 7:3 were mixed as the solvent, 2 g / L of cobalt nitrate was used as the supporting electrolyte, 1.5 g / L of terephthalic acid was used as the antibacterial active substance, and 3 g / L of CTAB was used as the auxiliary deposition surfactant to prepare an electrodeposition solution;

[0036] Through a three-electrode system (saturated calomel as the reference electrode), at a temperature of 30 °C, a liquid-like surface was prepared by electrodepositing at -1.0 V for 300 s on TA2 type titanium metal. Cathodic electrodeposition-induced local alkalization promoted the deprotonation of terephthalic acid and the coordination of Co in the cobalt nitrate supporting electrolyte 2+ to in-situ grow antibacterial and antifouling active nanomaterial sites (eNPs) on the polymer molecular brush link, and it was cured at 60 °C for 1 hour to obtain a functionalized liquid-like surface with "beaded" antibacterial active sites (Ti / eLLS@eNPs).

[0037] After testing, the antibacterial rate of this Ti / eLLS@eNPs against Escherichia coli was 95%, and the antibacterial rate against Staphylococcus aureus was 98%.

[0038] Example 3:

[0039] The technological process of the preparation method of the antibacterial liquid-like super-slippery surface involved in this example is as follows:

[0040] 6 g / L of aqueous fluorosilicone oil was functionalized with 0.6 g / L of KH560 at the end group and used as the raw material for constructing the liquid-like polymer molecular brush. Ethanol and water with a volume ratio of 4:1 were mixed as the solvent, 2.5 g / L of copper nitrate was used as the supporting electrolyte, 2.4 g / L of terephthalic acid was used as the antibacterial active substance, and 4 g / L of CTAB was used as the auxiliary deposition surfactant to prepare an electrodeposition solution; Through a three-electrode system (saturated calomel as the reference electrode), at a temperature of 35 °C, a liquid-like surface was prepared by electrodepositing at -1.2 V for 200 s on TC4 type titanium metal. Cathodic electrodeposition-induced local alkalization promoted the deprotonation of terephthalic acid and the coordination of Cu in the copper nitrate supporting electrolyte 2+ to in-situ grow antibacterial and antifouling active nanomaterial sites (eNPs) on the polymer molecular brush link, and it was cured at 100 °C for 30 minutes to obtain a functionalized liquid-like surface with "beaded" antibacterial active sites (Ti / eLLS@eNPs).

[0041] After testing, the antibacterial rate of this Ti / eLLS@eNPs against Escherichia coli was 99%, and the antibacterial rate against Staphylococcus aureus was 99%.

[0042] Example 4:

[0043] The technological process of the preparation method of the antibacterial liquid-like super-slippery surface involved in this embodiment is as follows:

[0044] 7 g / L of aqueous amino silicone oil (aqueous amino-terminated polydimethylsiloxane) is end-functionalized with 0.8 g / L of KH560 as the raw material for constructing the liquid-like polymer molecular brush. Ethanol and water with a volume ratio of 7:3 are used as the solvent, 2 g / L of zinc nitrate is used as the supporting electrolyte, 0.2 g / L of penicillamine is used as the antibacterial active substance, and 1.8 g / L of CTAB is used as the auxiliary deposition surfactant to prepare an electrodeposition solution;

[0045] Through a three-electrode system (saturated calomel as the reference electrode), at a temperature of 35 °C, a liquid-like surface is prepared by electrodeposition on Ti80 type titanium metal at -1.5 V for 900 s. Cathodic electrodeposition local alkalization promotes the deprotonation of penicillamine and the coordination of Zn in the zinc nitrate supporting electrolyte. Antibacterial and antifouling active nanomaterial sites (eNPs) are in-situ grown on the polymer molecular brush chain segments, and it is cured at 120 °C for 1 hour to obtain a functionalized liquid-like surface with "beaded" antibacterial active sites (Ti / eLLS@eNPs). 2+ After testing, the antibacterial rate of this Ti / eLLS@eNPs against Escherichia coli is 97%, and the antibacterial rate against Staphylococcus aureus is 98%.

[0046] Example 5:

[0047] The technological process of the preparation method of the antibacterial liquid-like super-slippery surface involved in this embodiment is as follows:

[0048] 3 g / L of aqueous mercapto silicone oil (aqueous mercapto-terminated polydimethylsiloxane) is end-functionalized with 0.3 g / L of KH560 as the raw material for constructing the liquid-like polymer molecular brush. Ethanol and water with a volume ratio of 4:1 are used as the solvent, 0.8 g / L of copper nitrate is used as the supporting electrolyte, 1.4 g / L of terephthalic acid is used as the antibacterial active substance, and 3.6 g / L of CTAB is used as the auxiliary deposition surfactant to prepare an electrodeposition solution; Through a three-electrode system (saturated calomel as the reference electrode), at a temperature of 40 °C, a liquid-like surface is prepared by electrodeposition on TA2 type titanium metal at -1.8 V for 60 s. Cathodic electrodeposition local alkalization promotes the deprotonation of terephthalic acid and the coordination of Cu in the copper nitrate supporting electrolyte. Antibacterial and antifouling active nanomaterial sites (eNPs) are in-situ grown on the polymer molecular brush chain segments, and it is cured at 150 °C for 2 hours to obtain a functionalized liquid-like surface with "beaded" antibacterial active sites (Ti / eLLS@eNPs).

[0049] 2+ coordination, and antibacterial and antifouling active nanomaterial sites (eNPs) are in-situ grown on the polymer molecular brush chain segments, and it is cured at 150 °C for 2 hours to obtain a functionalized liquid-like surface with "beaded" antibacterial active sites (Ti / eLLS@eNPs).

[0050] After testing, the antibacterial rate of the Ti / eLLS@eNPs against Escherichia coli was 99%, and the antibacterial rate against Staphylococcus aureus was 99%.

Claims

1. A method for preparing an antibacterial liquid-like super-slippery surface, characterized in that: By electrochemically "stringing beads" on liquid-like polymer molecular brushes, antifouling nanoactive sites with a bead-chain topological structure were constructed in situ to prepare an antibacterial liquid-like functionalized super-wetting surface with multiple marine antifouling mechanisms.

2. The method for preparing an antibacterial liquid-like super-slippery surface according to claim 1, characterized in that: The process includes the following steps:

1. Preparation of electrodeposition solution Adding metal nitrate, functionalized lubricant, silane coupling agent, hexadecyltrimethylammonium bromide and carboxyl-containing antibacterial agent into a mixed solvent of water and ethanol to prepare an electrodeposition solution; 2. Electrodeposition Adding an electrodeposition solution into an electrolytic cell, using a saturated calomel electrode as a reference electrode, a conductive substrate as a working electrode, and a platinum mesh / platinum sheet as a counter electrode, and performing electrodeposition to obtain a liquid-like film layer; 3. Curing The liquid-like film layer is cured.

3. The method for preparing an antibacterial liquid-like super-slippery surface according to claim 2, characterized in that: The metal nitrate in step 1 includes one or more of zinc nitrate, cobalt nitrate and copper nitrate; The functionalized lubricating fluid includes one or more of water-based amino silicone oil, water-based mercapto silicone oil, and water-based fluorinated lubricating oil; The carboxyl-containing antibacterial agent includes one or more of trimesic acid, terephthalic acid, and penicillamine.

4. The method for preparing an antibacterial liquid-like super-slippery surface according to claim 3, characterized in that: The conductive substrate in step 2 includes conductive glass or metal devices; The electrodeposition potential is -0.9 V to -1.8 V, the time is 30 s to 20 min, and the temperature is 20°C to 50°C.

5. The method for preparing an antibacterial liquid-like super-slippery surface according to claim 4, characterized in that: The curing temperature in step 3 is 20° C. to 150° C., and the curing time is 0.5 h to 5 h.

6. A method for preparing an antibacterial liquid-like super-slippery surface according to any one of claims 2 to 5, characterized in that: The volume ratio of water to ethanol is 4:1-1:4; the amount of metal nitrate in each liter of mixed solvent is 0.5-3; the amount of functionalized lubricant is 1-10g; the amount of silane coupling agent is 0.1-1g; the amount of hexadecyltrimethylammonium bromide is 0.1-5g; and the amount of carboxyl antibacterial agent is 0.1-5g.

7. The method for preparing an antibacterial liquid-like super-slippery surface according to claim 6, characterized in that: The aqueous amino silicone oil was functionalized with KH560 end groups as the raw material for constructing liquid-like polymer molecular brushes, ethanol and water were mixed as a mixed solvent, zinc nitrate was used as a supporting electrolyte, trimesic acid was used as an antibacterial active substance, and CTAB was used as an auxiliary deposition surfactant to prepare an electrodeposition solution; Using a three-electrode system, the electrodeposition was carried out on a TC4 titanium alloy at a temperature of 25°C for 200 s at a voltage between -0.8 V and -1.6 V. The cathode electrodeposition was used to locally alkalize the trimesic acid to promote the deprotonation of the Zn in the zinc nitrate supporting electrolyte. 2+ Coordination, in situ growth of antibacterial and antifouling active nanomaterial sites on the polymer molecular brush chain links, and curing at 30°C for 5 hours to obtain a functionalized liquid-like surface with "beaded" antibacterial active sites under different deposition potentials.

8. The method for preparing an antibacterial liquid-like super-slippery surface according to claim 7, characterized in that: The dosage of water-based amino silicone oil is 5g / L; The dosage of KH560 is 0.5g / L; The volume ratio of ethanol to water is 4:1; The dosage of zinc nitrate is 1g / L; The dosage of trimesic acid is 1g / L; The dosage of CTAB is 0.5 g / L.

Images