A temperature-sensitive gated intelligent protective coating for detection sensors, its preparation method, and its application.

Abstract

This invention relates to the field of metal corrosion protection technology, specifically to a temperature-sensitive gated intelligent protective coating for a detection sensor. Using a film-forming system as the matrix, dendritic mesoporous silica is employed as a micro / nano container carrier. A plant-derived compound corrosion inhibitor, formed by combining anemone leaf extract and oak leaf extract, is loaded within the pores. A PNIPAM-based temperature-sensitive polymer gated layer is constructed by introducing reactive functional groups onto the outer surface of the carrier via a silane coupling agent. This results in a temperature-sensitive gated corrosion-inhibiting nanocontainer that combines high loading capacity, reversible gated operation, and good matrix compatibility. Furthermore, this application couples the original temperature detection capability of the detection sensor with the gated corrosion-inhibiting nanocontainer. Local temperature anomalies are used as trigger signals to open the pores of the temperature-sensitive gated layer under specific conditions, releasing the corrosion inhibitor. After forming a protective film on the metal surface, the layer returns to a relatively closed state, completing the intelligent protection process.

Description

Technical Field

[0001] This invention relates to the field of metal corrosion protection technology, specifically to a temperature-sensitive gated intelligent protective coating for detection sensors, its preparation method, and its application. Background Technology

[0002] With the continuous development of intelligent sensing technology, marine equipment, mining equipment, and chemical online monitoring devices often require the deployment of various sensors in environments with high humidity, high salinity, fluctuating acid and alkali levels, and multiple corrosive media. These sensors are used to collect real-time information such as temperature, pH, conductivity, dissolved oxygen, corrosive ion concentration, and equipment operating status. These sensors operate under these complex conditions for extended periods, and corrosion can lead to decreased measurement accuracy, signal drift, and unstable response. It can also cause seal damage, abnormal electrical connections, and increased maintenance frequency, ultimately affecting the continuous and stable operation of the entire intelligent monitoring system. Particularly vulnerable are the metal-sensitive parts of the sensors, such as electrode bases, probe housings, sealing flanges, metal leads, and terminals, which are prone to pitting corrosion, crevice corrosion, or localized failure in gaps, scratches, interface joints, and areas of localized stress concentration. Therefore, providing long-term, accurate, and environmentally friendly corrosion protection for the metal-sensitive parts of the sensors has become a critical technical requirement for ensuring the stable operation of intelligent monitoring systems under complex conditions.

[0003] Currently, corrosion protection measures for the metal-sensitive parts of detection sensors mainly rely on epoxy and polyurethane organic coatings or potting layers, which delay the intrusion of corrosive media such as water, oxygen, and chloride ions through physical barriers. However, these traditional coatings are essentially passive protection systems. When local defects such as scratches, pinholes, stress cracks, or interface delamination occur in the coating, corrosive media preferentially accumulate along the defects and rapidly reach the metal / coating interface, leading to pitting corrosion, crevice corrosion, or localized electrochemical failure. Especially for detection sensors with temperature-compensated probes, sealing flanges, terminals, and metal housings, corrosion often first occurs in small, highly sensitive localized areas, where traditional passive barrier coatings struggle to respond promptly.

[0004] To improve the sustained protection capability after damage, self-healing anti-corrosion coatings have gradually become a research focus. Existing technologies have attempted to directly incorporate corrosion inhibitors into coatings, but these inhibitors are prone to premature precipitation, migration, and loss during the coating film formation stage and early service life, reducing utilization and potentially weakening the coating's mechanical properties, adhesion, and dielectric stability. Meanwhile, there are also studies using micro / nano containers to load corrosion inhibitors to construct external self-healing anti-corrosion systems. While this can reduce early leakage to some extent, existing carriers often employ conventional spherical mesoporous silica or hollow microsphere structures, which typically suffer from limited loading capacity, long diffusion paths, difficulty in precisely controlling the release rate, and generally poor compatibility with resin matrices. These limitations make it difficult to meet the requirements for "small-volume, rapid, on-demand" release and long-term storage at localized defects in sensors. Furthermore, current corrosion inhibitor release relies solely on passive triggering methods such as moisture, smoke, or pH changes, often lagging behind the development of localized corrosion in the sensor, lacking timely and effective triggering methods.

[0005] Therefore, it is of great significance to study an intelligent anti-corrosion coating for detection sensors in complex working conditions, which can achieve timely and effective triggering and on-demand release and self-repair at local defects. Summary of the Invention

[0006] To address the technical problems in existing technologies, the present invention aims to provide a temperature-gated intelligent protective coating for detection sensors and its preparation method. This solves the problems of existing technologies, such as the reliance on passive barrier protection for detection sensors, premature leakage of corrosion inhibitors, and lack of precise control over release. The temperature-gated intelligent protective coating of this application uses dendritic mesoporous silica as a high-porosity micro / nano container, a plant-derived compound corrosion inhibitor formed by combining anemone leaf extract and oak leaf extract as the active protective component, and a reversible gating layer constructed with a PNIPAM-based temperature-sensitive polymer. This ensures the overall barrier properties of the coating while enabling on-demand release and self-repair at local defects. The application of the temperature-gated intelligent protective coating in the anti-corrosion coating of sensors for online monitoring of industrial aqueous solutions is also provided.

[0007] To achieve the above objectives, the technical solution provided by the present invention is as follows: On one hand, the present invention provides a temperature-gated intelligent protective coating for a detection sensor, comprising: a film-forming matrix and temperature-gated corrosion-inhibiting nanocapsules dispersed in the film-forming matrix, wherein the amount of the temperature-gated corrosion-inhibiting nanocapsules added is 0.5-5.0 wt% of the solid content of the film-forming matrix; The temperature-gated corrosion-inhibiting nanocontainer comprises: 100 parts of a porous carrier, 30-200 parts of a corrosion inhibitor, and 20-350 parts of a temperature-sensitive polymer gating layer. The corrosion inhibitor is loaded in the pores of the porous carrier, and the temperature-sensitive polymer gating layer is coated on the outer surface of the porous carrier. The above parts are by weight.

[0008] The working principle of this invention is as follows: Dendritic mesoporous silica provides radially open channels and high pore volume, which increases the loading capacity of plant-derived compound corrosion inhibitors and shortens the release path; the PNIPAM-based temperature-sensitive polymer gated layer is in a hydrated and swollen state below the LCST, which can seal the pores and inhibit early leakage of the corrosion inhibitor; when the local temperature rises to near or above the LCST, it undergoes dehydration and shrinkage, opening the channels and releasing the corrosion inhibitor; the released polyphenols, tannins, flavonoids, and other active ingredients are adsorbed on the metal surface and form a composite protective film involving oxygen-containing functional groups. The silane-modified functional groups on the surface of the nanocontainer can also enhance the interfacial bonding between it and film-forming substrates such as epoxy resin, epoxy-polyurethane, or acrylic resin, enabling the coating to maintain barrier properties and adhesion while possessing temperature-responsive self-healing capabilities.

[0009] Based on the above technical solution, the film-forming matrix is ​​one or more of epoxy resin, epoxy-polyurethane, or acrylic resin.

[0010] Based on the above technical solution, the porous carrier in the temperature-gated corrosion-inhibiting nanocontainer is dendritic mesoporous silica, whose pore structure includes radial pores and hierarchical pore structures; the average particle size is 50-300 nm, the specific surface area is 500-1500 m² / g, and the pore volume is 0.5-2.0 cm³ / g.

[0011] Based on the above technical solution, the corrosion inhibitor in the temperature-gated corrosion-inhibiting nanocontainer is a plant-derived compound corrosion inhibitor, including anemone leaf extract and oak leaf extract in a mass ratio of 1:(0.5-2.0). Preferably, the mass ratio of the anemone leaf extract and oak leaf extract is 1:1.

[0012] Preferably, a plant-derived compound corrosion inhibitor is used to achieve green and efficient utilization of the inhibitor. The polyphenols, flavonoids, and oxygen-containing functional groups in anemone leaf extract can complex, hydrogen-bond, or electrostatically adsorb onto the metal surface; the tannins, polyphenols, and phenolic hydroxyl structures in oak leaf extract can enhance the density of the adsorption film. The combination of these two components allows for adsorption onto the metal surface through phenolic hydroxyl, carbonyl, and aromatic structures, synergistically forming a composite protective film. By using temperature-gated corrosion-inhibiting nanocontainer loading and temperature-gated control, the ineffective consumption of the corrosion inhibitor during the non-corrosion stage can be reduced, improving utilization efficiency while simultaneously ensuring environmental friendliness and corrosion prevention.

[0013] Based on the above technical solution, the temperature-sensitive polymer gated layer in the temperature-sensitive gated corrosion-inhibiting nanocontainer is poly(N-isopropylacrylamide) PNIPAM or a copolymer containing PNIPAM segments; the temperature-sensitive polymer gated layer is in a swollen state below the lower critical dissolution temperature (LCST) to block the pores, and shrinks above the LCST to open the pores.

[0014] This application constructs a synergistic structure of a dendritic mesoporous carrier and a PNIPAM-based thermosensitive polymer-gated layer. The dendritic mesoporous silica possesses a hierarchical pore structure radiating radially outward from the center, along with a large specific surface area and pore volume, which is beneficial for increasing the loading capacity of plant-derived corrosion inhibitors and shortening the mass transfer path. The PNIPAM-based polymer, on the other hand, endows the pores with reversible opening and closing capabilities. The synergistic effect of these two components achieves a balance between high loading capacity, low early release, and rapid response release, outperforming conventional ungated or ordinary spherical mesoporous carrier systems.

[0015] On the other hand, this application provides a method for preparing the aforementioned temperature-sensitive gated intelligent protective coating for detection sensors, comprising the following steps: Step 1: Prepare dendritic silica particles containing a template agent; Step 2: The template agent-containing dendritic silica particles obtained in Step 1 are subjected to template agent removal and surface hydroxylation treatment to open the channels and obtain dendritic mesoporous silica. Step 3: Prepare anemone leaf extract and oak leaf extract and compound them to obtain a plant-derived compound corrosion inhibitor. Load the plant-derived compound corrosion inhibitor into the dendritic mesoporous silica channels of Step 2 to obtain a corrosion inhibitor-loaded porous carrier. Step 4: Silane coupling agent is added to the porous carrier loaded with corrosion inhibitor obtained in step 3 for surface modification, introducing reactive functional groups that are combined with the temperature-sensitive polymer gated layer, and the temperature-sensitive polymer gated layer is constructed through epoxy ring-opening reaction or free radical polymerization / grafting reaction to obtain temperature-sensitive gated corrosion-inhibiting nanocontainer. Step 5: Add the temperature-gated corrosion-inhibiting nanocontainer obtained in Step 4 to the film-forming matrix and disperse it to obtain the temperature-gated intelligent protective coating for the detection sensor.

[0016] Based on the above technical solution, step one involves preparing dendritic silica particles containing a template agent using an emulsion-sol-gel method, which includes the following processes: Hexadecyltrimethylammonium bromide (CTAB) was dissolved in deionized water, and then ammonia and ether were added to form an emulsion system. Ethanol and tetraethyl orthosilicate (TEOS) were added sequentially under stirring to form a silica framework. The resulting product was washed to obtain dendritic silica particles containing a template agent.

[0017] Based on the above technical solution, the preparation of dendritic mesoporous silica in step two includes the following process: The dendritic silica particles containing template agent obtained in step one are dispersed in an ethanol solution of ammonium nitrate and refluxed to remove the template agent and form open channels. After washing and drying, dendritic mesoporous silica is obtained.

[0018] Based on the above technical solution, step three involves obtaining a corrosion inhibitor-loaded porous carrier using a solvent impregnation method, which includes the following processes: (1) Preparation of plant-derived compound corrosion inhibitor: Anemone leaves and oak leaves were washed, dried and crushed respectively, and added to ethanol solution respectively. The mixture was magnetically stirred at room temperature, filtered and distilled to remove the solvent, and extracts of anemone leaves and oak leaves were obtained. After mixing, plant-derived compound corrosion inhibitor was obtained. (2) Corrosion inhibitor loading: Using ethanol as solvent, the dendritic mesoporous silica and plant-derived compound corrosion inhibitor are mixed at a mass ratio of 1:(0.5~2.0), stirred, separated, washed and dried to obtain the corrosion inhibitor.

[0019] Based on the above technical solution, the construction of the temperature-sensitive polymer gated layer in step four includes the following process: The corrosion inhibitor-loaded porous carrier from step three was dispersed in ethanol, and a silane coupling agent was added for modification. Then, N-isopropylacrylamide, acrylamide, and azobisisobutyronitrile were added for polymerization to obtain a temperature-sensitive gated corrosion-inhibiting nanocontainer. The silane coupling agent is 3-glycidyl ether propyltrimethoxysilane GPTMS; the mass ratio of N-isopropylacrylamide to acrylamide is 1:(0.3-1.0), and the amount of azobisisobutyronitrile added is 0.5-3.0 wt% of the total mass of N-isopropylacrylamide and acrylamide.

[0020] The acrylamide is used to adjust the hydrophilicity, swelling degree, and response behavior near LCST of the PNIPAM-based polymer, and to improve the compatibility between the gated layer and the coating substrate.

[0021] On the other hand, this application provides an application of the temperature-sensitive gated intelligent protective coating described above in the anti-corrosion coating of an industrial aqueous solution online monitoring sensor. The industrial aqueous solution online monitoring sensor includes a temperature detection unit, which senses local temperature anomaly signals as control commands for opening and closing the temperature-sensitive polymer gated layer.

[0022] Preferably, the temperature detection unit is a Pt100 / Pt1000 temperature compensation probe integrated into the sensor, or a fiber Bragg grating (FBG) sensor pre-embedded at the interface between the coating and the metal substrate.

[0023] This invention addresses the technical gap in existing technologies where sensors can measure temperature but not prevent corrosion. Instead of simply introducing temperature-sensitive controlled-release materials, it directly converts the localized temperature anomaly signals obtained from existing Pt100 / Pt1000 temperature compensation probes or pre-embedded FBG sensors into gate opening commands. This upgrades the protection system from a traditional passive barrier to a perceptible and responsive active intelligent protection system, enhancing the solution's adaptability to various scenarios and its engineering value.

[0024] For the design of typical corrosive devices such as industrial aqueous solution online monitoring sensors and marine sensors, this technology can be directly integrated into existing epoxy or related encapsulation / protective coating systems. It adapts to the protection needs of high-risk localized corrosion areas such as electrode-insulation layer junctions, sealing gaps, and wiring terminals, demonstrating good engineering feasibility. Furthermore, it does not significantly increase structural complexity, eliminating the need for an additional external triggering device; instead, it reuses the sensor's existing temperature detection unit to acquire signals. Simultaneously, the small particle size and controllable addition amount of the nanocapsules help improve long-term corrosion resistance while maintaining coating film-forming properties, adhesion, and sensor application compatibility.

[0025] The beneficial effects of the technical solution provided by this invention are as follows: This invention provides a temperature-gated intelligent protective coating for a detection sensor. The coating uses epoxy resin, epoxy-polyurethane, or other suitable film-forming systems as the matrix, and employs dendritic mesoporous silica as a micro / nano container carrier. A plant-derived compound corrosion inhibitor, formed by combining anemone leaf extract and oak leaf extract, is loaded into the pores of the silica. After introducing reactive functional groups on the outer surface of the carrier through a silane coupling agent, a PNIPAM-based temperature-sensitive polymer gating layer is constructed, thereby forming a temperature-gated corrosion-inhibiting nanocontainer with high loading capacity, reversible gating, and good matrix compatibility.

[0026] Meanwhile, this application couples the original temperature detection capability of the detection sensor with a gated corrosion-inhibiting nanocontainer. By using local temperature anomalies as a trigger signal, the temperature-sensitive gated layer opens its channels and releases the corrosion inhibitor under specific conditions. After forming a protective film on the metal surface, it returns to a relatively closed state. This constructs a closed-loop intelligent protection mechanism of "sensor temperature perception - temperature-sensitive gate opening - plant-derived compound corrosion inhibitor release - metal surface film formation and repair", thereby improving the timeliness, accuracy and sustainability of the anti-corrosion coating protection.

[0027] Furthermore, when the temperature-gated intelligent protective coating is used as an anti-corrosion coating for industrial aqueous solution online monitoring sensors, the temperature signal detected when local abnormal temperature fluctuations are detected can serve as the basis for triggering the opening and closing of the temperature-sensitive polymer gating layer. This causes the PNIPAM-based temperature-sensitive polymer to undergo a reversible volume phase transition and open mesoporous channels, thereby driving the directional release of plant-derived corrosion inhibitors at the defect site, forming an adsorption protective film on the metal surface. After the environment recovers, the temperature-sensitive polymer gating layer tends to close again, inhibiting continuous leakage. Compared with traditional methods that directly add corrosion inhibitors or release without gating, this invention can reduce early leakage, improve the utilization rate and repair accuracy of corrosion inhibitors, and enhance the coupling with the application scenarios of detection sensors.

[0028] This approach combines green corrosion inhibitors, hierarchical porous nanocarriers, temperature-sensitive reversible gating, and sensor temperature signal-linked triggering to form a holistic technical route that differs from existing single controlled release, single carrier, or single corrosion inhibitor solutions. It significantly reduces early leakage of corrosion inhibitors in complex aqueous corrosive environments, improves the efficiency of local defect repair, extends the service life of key metal components of sensors, and meets green and environmental protection requirements, thus showing good application prospects. Attached Figure Description

[0029] Figure 1 Transmission electron microscope (TEM) image of the dendritic mesoporous silica nanoparticles prepared for this invention.

[0030] Figure 2 Transmission electron microscope (TEM) image of the spherical mesoporous silica nanoparticles prepared in this invention.

[0031] Figure 3 The three-dimensional electrochemical impedance spectroscopy (EIS) spectra of the protective coatings prepared in Example 1, Comparative Example 1 and Comparative Example 2 at different immersion times are shown.

[0032] Figure 4 The impedance modulus of the protective coating prepared in Example 1 of this invention changes with time under 0.01 Hz conditions during immersion in 3.5 wt.% NaCl solution.

[0033] Figure 5 The impedance modulus of the protective coating prepared for Comparative Example 2 (spherical mesoporous silica nanocontainer) of the present invention changes with time under 0.01 Hz conditions during immersion in 3.5 wt.% NaCl solution.

[0034] Figure 6 The impedance modulus of the protective coating prepared for Comparative Example 1 of this invention (without the introduction of the PNIPAM-based thermosensitive polymer gated layer) changes with time under 0.01 Hz conditions during immersion in 3.5 wt.% NaCl solution.

[0035] Figure 7 Thermogravimetric analysis curves of anemone leaf extract (AC), oak leaf extract (QR), dendritic mesoporous silica (DMSN), dendritic mesoporous silica loaded with plant-derived compound corrosion inhibitors (DMSN@Inh), and dendritic mesoporous silica nanocontainers coated with PNIPAM (DMSN@Inh@PNIPAM).

[0036] Figure 8 Thermogravimetric analysis curves of anemone leaf extract (AC), oak leaf extract (QR), spherical mesoporous silica (S-MSN), spherical mesoporous silica loaded with plant-derived compound corrosion inhibitors (S-MSN@Inh), and PNIPAM-coated spherical mesoporous silica nanocontainers (S-MSN@Inh@PNIPAM). Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items. It should be understood that, unless otherwise specified, all the various materials used in this invention are commercially available.

[0039] Example 1 This embodiment provides a temperature-gated intelligent protective coating for a detection sensor, comprising: a film-forming matrix and temperature-gated corrosion-inhibiting nanocontainers dispersed in the film-forming matrix, wherein the amount of the temperature-gated corrosion-inhibiting nanocontainers added is 3.0 wt% of the solid content of the film-forming matrix; wherein the film-forming matrix is ​​epoxy resin E-44; The temperature-gated corrosion-inhibiting nanocontainer comprises: a porous carrier, a corrosion inhibitor, and a temperature-sensitive polymer gating layer. The corrosion inhibitor is loaded within the pores of the porous carrier, and the temperature-sensitive polymer gating layer is coated on the outer surface of the porous carrier. By mass, the porous carrier comprises 100 parts, the corrosion inhibitor comprises 50 parts, and the temperature-sensitive polymer gating layer comprises 320 parts.

[0040] This embodiment provides a method for preparing a temperature-sensitive gated intelligent protective coating for a detection sensor, comprising the following steps: Step 1: Prepare dendritic silica particles containing template agent; add 0.5g CTAB and 0.6g urea to 150mL deionized water, stir and dissolve at 80℃, then add 2.5mL LTEOS dropwise and react for 6h; after centrifugation and washing, obtain dendritic silica particles containing template agent.

[0041] Step 2: The dendritic silica particles containing template agent obtained in Step 1 are dispersed in 100 mL of ethanol solution containing 1 g of ammonium nitrate, refluxed at 60 °C for 6 h to remove the template, so as to form open channels. After washing and drying, dendritic mesoporous silica DMSN is obtained.

[0042] Step 3: Prepare anemone leaf extract and oak leaf extract and compound them to obtain a plant-derived compound corrosion inhibitor. Load the plant-derived compound corrosion inhibitor into the dendritic mesoporous silica channels of Step 2 to obtain a corrosion inhibitor-loaded porous carrier. (1) Preparation of plant-derived compound corrosion inhibitor: Anemone leaves and oak leaves were washed, dried and crushed to a particle size of less than 0.5 mm. 15 g of each was weighed and added to 250 mL of ethanol solution. The mixture was magnetically stirred at room temperature for 48 h. After filtration, the solvent was removed by rotary evaporator at 40 °C to obtain two plant extracts. They were mixed at a mass ratio of 1:1 to obtain the plant-derived compound corrosion inhibitor.

[0043] (2) Corrosion inhibitor loading: Disperse 0.5g of DMSN in 50mL of ethanol, add 0.25g of compound corrosion inhibitor, stir at room temperature for 24h, centrifuge, wash and dry to obtain DMSN@Inh.

[0044] Step four, preparation of the temperature-sensitive gated corrosion-inhibiting nanocontainer: 0.5 g DMSN@Inh was dispersed in 50 mL ethanol, and 1 mL LPTMS was added. The mixture was reacted at 70 °C for 6 h. Subsequently, a PNIPAM-PAAm copolymer solution obtained by polymerizing 1.0 g NIPAM, 0.6 g acrylamide, and 0.02 g AIBN at 70 °C was added, and the mixture was reacted at 50 °C for 24 h to obtain the DMSN@Inh@PNIPAM nanocontainer. Based on 100 parts of porous carrier, the temperature-sensitive polymer gated layer consisted of 320 parts.

[0045] Step 5: Mix 100 parts of epoxy resin (E-44), 1 part of dispersant, and 50 parts of anti-rust pigment. After high-speed dispersion, add 3wt% temperature-sensitive gated corrosion-inhibiting nano-container, grind to a fineness ≤40μm, add curing agent and stir evenly to obtain temperature-sensitive gated intelligent protective coating for detection sensors.

[0046] This embodiment provides an application of a temperature-sensitive gated intelligent protective coating for a sensor in the anti-corrosion coating of an industrial aqueous solution online monitoring sensor.

[0047] Example 2: The difference from Example 1 is that: The porous carrier comprises 100 parts, the corrosion inhibitor comprises 30 parts, and the temperature-sensitive polymer gating layer comprises 20 parts.

[0048] In step three, the loading ratio of the plant-derived compound corrosion inhibitor is adjusted: the mass ratio of DMSN to the plant-derived compound corrosion inhibitor is 1:0.3 (i.e., 0.5g of DMSN is added to 0.15g of corrosion inhibitor), and the corrosion inhibitor is 30 parts based on 100 parts of porous carrier.

[0049] In step four, 0.5 g DMSN@Inh was dispersed in 50 mL ethanol, 1 mL LPTMS was added, and the mixture was reacted at 70 °C for 6 h. Subsequently, a PNIPAM-PAAm copolymer solution obtained by polymerizing 0.06 g NIPAM, 0.04 g acrylamide, and 0.001 g AIBN at 70 °C was added, and the mixture was reacted at 50 °C for 24 h to obtain DMSN@Inh@PNIPAM nanocontainers. The temperature-sensitive polymer gate layer consisted of 20 parts per 100 parts of porous carrier.

[0050] In step five, the amount of temperature-gated corrosion-inhibiting nanocontainer added is 2.0 wt%.

[0051] The remaining steps are the same as in Example 1.

[0052] Example 3: The difference from Example 1 is that: The porous carrier comprises 100 parts, the corrosion inhibitor comprises 200 parts, and the temperature-sensitive polymer gating layer comprises 350 parts.

[0053] In step three, the loading ratio of the plant-derived compound corrosion inhibitor is adjusted: the mass ratio of DMSN to the plant-derived compound corrosion inhibitor is 1:2.0 (i.e., 0.5g of DMSN is added to 1.0g of corrosion inhibitor), and the corrosion inhibitor is 200 parts based on 100 parts of porous carrier.

[0054] In step four, the mass ratio of N-isopropylacrylamide (NIPAm) to acrylamide in the PNIPAM-PAAm copolymer is adjusted to 2:1, and the total amount of NIPAM and acrylamide is adjusted to 1.75g, of which NIPAM is 1.17g and acrylamide is 0.58g; the amount of azobisisobutyronitrile (AIBN) added is 1.25wt% of the total mass of N-isopropylacrylamide and acrylamide; based on 100 parts of porous carrier, the temperature-sensitive polymer gate layer is 350 parts.

[0055] In step five, the amount of temperature-gated corrosion-inhibiting nanocontainer added is 4.0 wt%.

[0056] The protective coating obtained in Example 3 was subjected to the same electrochemical impedance spectroscopy and scratch immersion observation as in Example 1. The results showed that, due to the increased content of the temperature-sensitive gating layer, early corrosion inhibitor leakage was further reduced in Example 3, and the decrease in low-frequency impedance modulus during the initial immersion phase was less than in Comparative Example 1. Furthermore, an impedance recovery trend was observed even after the local temperature rose to near the LCST, indicating that it possesses temperature-sensitive response release capability. Compared to Example 1, the gating layer in Example 3 is thicker, resulting in enhanced long-term sealing capability, but the release response speed is slightly reduced. Therefore, it can be considered a preferred formulation prioritizing long-term storage stability.

[0057] In step five, the amount of temperature-gated corrosion-inhibiting nanocontainer added is 4.0 wt%.

[0058] The remaining steps are the same as in Example 1.

[0059] Example 4: This embodiment provides a linkage verification of the anti-corrosion coating formed by coupling a Pt100 temperature probe with a temperature-sensitive gated intelligent protective coating. The specific process is as follows: (1) Integration of temperature probe: The Pt100 temperature compensation probe is attached to the surface of the 316L stainless steel dissolved oxygen electrode base coated with the anti-corrosion coating of the temperature-sensitive gated intelligent protective coating obtained in Example 1. Thermal grease is applied between the probe and the coating to ensure good heat conduction. The probe leads are connected to the sensor signal acquisition system.

[0060] (2) Linkage verification test: The above electrode base was placed in simulated chemical wastewater containing 3.5wt.% NaCl + 0.1mol / L H2SO4. The local aqueous solution was periodically heated with an electric heating rod (simulating process temperature fluctuations, the temperature was raised from 25℃ to 42℃ at a rate of about 2℃ / min, held for 30min and then naturally cooled, with a cycle of 2h). The Pt100 temperature data and the changes in electrode corrosion current density were recorded simultaneously.

[0061] (3) Results analysis: When the local temperature detected by Pt100 exceeded 32℃ (close to the LCST of the PNIPAM-PAAm copolymer), the electrode corrosion current density decreased from the initial 1.2×10⁻⁶ in the following 4 hours. -5 A / cm² decreased to 2.3×10 -7 The corrosion current density (A / cm², film formation after corrosion inhibitor release) exhibits a typical "rapid decline-stabilization" self-healing characteristic. In contrast, the control group without the anti-corrosion coating showed a continuous increase in corrosion current density to 5.7 × 10⁻⁶. -4 A / cm², the electrode completely failed after 7 days.

[0062] (4) Conclusion: The above results confirm that the local temperature signal captured by the Pt100 temperature probe built into the sensor can effectively trigger the on-demand release of the temperature-sensitive gate, realizing integrated intelligent protection of "sensing-response". This design does not require additional sensors and can directly reuse existing hardware, which greatly reduces the cost of modification.

[0063] Comparative Example 1: No temperature-sensitive polymer gating layer The difference from Example 1 is that: Instead of constructing the temperature-sensitive polymer gate layer in step four, DMSN@Inh is directly added to the epoxy coating system.

[0064] Comparative Example 2: Spherical Mesoporous Silica Nanocontainers The difference from Example 1 is that: In step two, instead of using dendritic mesoporous silica nanocarriers, commercially available conventional spherical mesoporous silica nanoparticles with a particle size of approximately 100–200 nm are used as carriers.

[0065] In step three, the plant-derived compound corrosion inhibitor is loaded into spherical mesoporous silica using the same method as in Example 1 to obtain SiO2@Inh.

[0066] In step four, the same method is used to construct a temperature-sensitive polymer-gated layer to obtain SiO2@Inh@PNIPAM nanocontainers.

[0067] In step five, 3.0 wt% of the epoxy coating system is added to prepare the interface between the anti-corrosion coating and the sensor metal substrate.

[0068] The remaining steps are the same as in Example 1.

[0069] Experimental Results and Performance Analysis Figure 1 and Figure 2 The images show TEM images of the dendritic mesoporous silica nanoparticles and spherical mesoporous silica nanoparticles prepared according to this invention. Figure 1 It can be seen that the dendritic mesoporous silica exhibits a typical radially divergent structure, with pores extending outward from the center, forming a multi-level open channel system; while Figure 2 The spherical mesoporous silica shown exhibits a relatively dense spherical structure with closely packed pores and long diffusion paths. In contrast, the dendritic mesoporous silica has a larger pore volume and a more open pore network, which is beneficial for the efficient loading and rapid mass transfer release of corrosion inhibitors, providing a structural basis for its excellent corrosion protection performance.

[0070] Figure 3Three-dimensional electrochemical impedance spectroscopy (EIS) spectra of the interfaces between the anti-corrosion coatings and the metal substrates of the detection sensors prepared in Examples 1, 1, and 2, under different immersion times. Figure 3 It can be seen that Example 1 maintained a high impedance modulus throughout the immersion process and showed a significant advantage in the low-frequency region, indicating that it has a stronger corrosion barrier capability. Meanwhile, the impedance of Example 1 showed a trend of first decreasing and then increasing over time, indicating that after the initial intrusion of the corrosion medium, the corrosion inhibitor could be effectively triggered to release and form a protective layer on the metal surface, thereby achieving self-healing. In contrast, Comparative Example 1, due to the lack of a PNIPAM temperature-sensitive polymer gated layer structure, lacked regulation of the corrosion inhibitor release process, and its impedance value gradually decreased over time; although Comparative Example 2 introduced a temperature-sensitive polymer gated layer structure, its overall impedance level was still lower than that of Example 1 due to the limitation of the spherical mesoporous structure.

[0071] Figures 4 to 6 The figures show the impedance modulus versus time at 0.01 Hz during immersion in 3.5 wt.% NaCl solution at the interface between the anti-corrosion coating and the metal substrate of the detection sensor in Examples 1, 2, and 1, respectively. Figure 4 It can be seen that the impedance modulus of Example 1 first decreases and then increases over time, eventually stabilizing, indicating that it can achieve continuous release and dynamic repair of the corrosion inhibitor in a corrosive environment; Figure 5 It can be seen that although Comparative Example 2 shows a certain recovery trend, its overall impedance level is significantly lower than that of Example 1, indicating that the spherical mesoporous structure has certain limitations in terms of corrosion inhibitor loading and release; Figure 6 It can be seen that the impedance value of Comparative Example 1 continues to decrease over time, indicating that the corrosion inhibitor in the temperature-sensitive polymer gated layer system is consumed rapidly, and the protection capability in the later stage is obviously insufficient.

[0072] Figure 7 and Figure 8 Thermogravimetric analysis curves are shown for dendritic and spherical mesoporous silica nanocontainer systems, respectively. Figure 7 It can be seen that the plant-derived compound corrosion inhibitor loaded on dendritic mesoporous silica exhibits significant weight loss in the temperature range of 200–400℃, corresponding to the thermal decomposition process of the corrosion inhibitor, with a final loading of approximately 31%; while Figure 8 The corrosion inhibitor loading of the spherical mesoporous silica was approximately 25%. Comparative results show that the dendritic mesoporous structure significantly outperforms the spherical structure in terms of corrosion inhibitor loading capacity, mainly due to its larger pore volume and more open pore structure.

[0073] This invention innovatively couples a Pt100 / Pt1000 temperature probe and a fiber Bragg grating sensor with a temperature-gated coating. Utilizing the high sensitivity of the FBG to localized temperature changes (accuracy ±0.1℃), it directly triggers the reversible opening and closing of the PNIPAM gating layer. Compared to traditional passive methods relying on moisture / salt spray diffusion for triggering, this design achieves "active sensing-instant response" to damage at the interface between the anti-corrosion coating and the metal substrate of the detection sensor. It can initiate the release of corrosion inhibitors before the defect has fully penetrated, significantly improving the timeliness and intelligence of protection.

[0074] In summary, this invention achieves efficient loading and controllable release of corrosion inhibitors by introducing dendritic mesoporous silica nanocontainers and a PNIPAM temperature-gated structure. Structural advantages (such as...) Figure 1 – Figure 2 ), load advantages (such as Figure 7 – Figure 8 ) and performance advantages (such as Figure 3 – Figure 6 The evidence corroborates each other, demonstrating that the anti-corrosion coating in this application has excellent long-term protective performance in complex industrial aqueous corrosive environments.

[0075] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0076] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A temperature-sensitive gate control intelligent protective coating for detection sensors, characterized in that, include: A film-forming substrate and temperature-sensitive gated corrosion-inhibiting nanocapsules dispersed in the film-forming substrate, wherein the amount of temperature-sensitive gated corrosion-inhibiting nanocapsules added is 0.5–5.0 wt% of the solid content of the film-forming substrate; The temperature-gated corrosion-inhibiting nanocontainer comprises: 100 parts of a porous carrier, 30-200 parts of a corrosion inhibitor, and 20-350 parts of a temperature-sensitive polymer gating layer. The corrosion inhibitor is loaded in the pores of the porous carrier, and the temperature-sensitive polymer gating layer is coated on the outer surface of the porous carrier. The above parts are by weight.

2. The intelligent protective coating for temperature-sensitive gate control according to claim 1, characterized in that, The film-forming matrix is ​​one or more of epoxy resin, epoxy-polyurethane, or acrylic resin.

3. The intelligent protective coating for temperature-sensitive gate control according to claim 1, characterized in that, The porous carrier in the temperature-gated corrosion-inhibiting nanocontainer is dendritic mesoporous silica, whose pore structure includes radial channels and hierarchical channels; the average particle size is 50-300 nm, the specific surface area is 500-1500 m² / g, and the pore volume is 0.5-2.0 cm³ / g.

4. The intelligent protective coating for temperature-sensitive gate control according to claim 1, characterized in that, The corrosion inhibitor in the temperature-gated corrosion-inhibiting nanocontainer is a plant-derived compound corrosion inhibitor, including anemone leaf extract and oak leaf extract in a mass ratio of 1:(0.5-2.0).

5. The intelligent protective coating for temperature-sensitive gate control according to claim 1, characterized in that, The temperature-sensitive polymer gated layer in the temperature-sensitive gated corrosion-inhibiting nanocontainer is poly(N-isopropylacrylamide) PNIPAM or a copolymer containing PNIPAM segments; the temperature-sensitive polymer gated layer is in a swollen state below the lower critical dissolution temperature (LCST) to block the pores of the porous carrier, and shrinks above the LCST to open the pores.

6. A method for preparing a temperature-sensitive gate-controlled intelligent protective coating for a detection sensor as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: Prepare dendritic silica particles containing a template agent; Step 2: The template agent-containing dendritic silica particles obtained in Step 1 are subjected to template agent removal and surface hydroxylation treatment to open the channels and obtain dendritic mesoporous silica. Step 3: Prepare anemone leaf extract and oak leaf extract and compound them to obtain a plant-derived compound corrosion inhibitor. Load the plant-derived compound corrosion inhibitor into the dendritic mesoporous silica channels of Step 2 to obtain a corrosion inhibitor-loaded porous carrier. Step 4: Silane coupling agent is added to the porous carrier loaded with corrosion inhibitor obtained in step 3 for surface modification, introducing reactive functional groups that are combined with the temperature-sensitive polymer gated layer, and the temperature-sensitive polymer gated layer is constructed through epoxy ring-opening reaction or free radical polymerization / grafting reaction to obtain temperature-sensitive gated corrosion-inhibiting nanocontainer. Step 5: Add the temperature-gated corrosion-inhibiting nanocontainer obtained in Step 4 to the film-forming matrix and disperse it to obtain the temperature-gated intelligent protective coating for the detection sensor.

7. The method for preparing a temperature-sensitive gate-controlled intelligent protective coating for a detection sensor according to claim 6, characterized in that, In step one, dendritic silica particles containing a template agent are prepared using the emulsion-sol-gel method. The process includes the following: Hexadecyltrimethylammonium bromide (CTAB) was dissolved in deionized water, and then ammonia and ether were added to form an emulsion system. Ethanol and tetraethyl orthosilicate (TEOS) were added sequentially under stirring to form a silica framework. The resulting product was washed to obtain dendritic silica particles containing a template agent.

8. The method for preparing a temperature-sensitive gate-controlled intelligent protective coating for a detection sensor according to claim 6, characterized in that, The preparation of dendritic mesoporous silica in step two includes the following processes: The dendritic silica particles containing template agent obtained in step one are dispersed in an ethanol solution of ammonium nitrate and refluxed to remove the template agent and form open channels. After washing and drying, dendritic mesoporous silica is obtained.

9. The method for preparing a temperature-sensitive gate-controlled intelligent protective coating for a detection sensor according to claim 6, characterized in that, Step three involves obtaining the corrosion inhibitor-loaded porous carrier using a solvent impregnation method, which includes the following processes: (1) Preparation of plant-derived compound corrosion inhibitor: Anemone leaves and oak leaves were washed, dried and crushed respectively, and added to ethanol solution respectively. The mixture was magnetically stirred at room temperature, filtered and distilled to remove the solvent, and extracts of anemone leaves and oak leaves were obtained. After mixing, plant-derived compound corrosion inhibitor was obtained. (2) Corrosion inhibitor loading: Using ethanol as solvent, the dendritic mesoporous silica and plant-derived compound corrosion inhibitor are mixed at a mass ratio of 1:(0.5~2.0), stirred, separated, washed and dried to obtain the corrosion inhibitor.

10. The method for preparing a temperature-sensitive gate-controlled intelligent protective coating for a detection sensor according to claim 6, characterized in that, The construction of the temperature-sensitive polymer gated layer in step four includes the following process: The corrosion inhibitor-loaded porous carrier from step three was dispersed in ethanol, and a silane coupling agent was added for modification. Then, N-isopropylacrylamide, acrylamide, and azobisisobutyronitrile were added for polymerization to obtain a temperature-sensitive gated corrosion-inhibiting nanocontainer. The silane coupling agent is 3-glycidyl ether propyltrimethoxysilane GPTMS; the mass ratio of N-isopropylacrylamide to acrylamide is 1:(0.3-1.0), and the amount of azobisisobutyronitrile added is 0.5-3.0 wt% of the total mass of N-isopropylacrylamide and acrylamide.

11. The application of a temperature-sensitive gated intelligent protective coating for a detection sensor as described in any one of claims 1 to 5 in an anti-corrosion coating for an industrial aqueous solution online monitoring sensor, characterized in that, The industrial aqueous solution online monitoring sensor includes a temperature detection unit, which senses local temperature anomaly signals as control commands for opening and closing the temperature-sensitive polymer gating layer.

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