A hygroscopic material based on polymer film and its preparation method and application

Abstract

The present invention is applicable to the technical field of hygroscopic materials, and provides a hygroscopic material based on a polymer film, a preparation method thereof, and an application thereof. The hygroscopic material is based on a polymer film, and an activated area is formed on the surface of the polymer film through plasma activation treatment, and then a modified area is formed on the surface of the polymer film through chemical adsorption and silanization reaction; the modified area is used to capture water vapor and condense and aggregate into droplets, and the activated area is used to reduce the sliding angle and contact angle hysteresis of the water droplets, and promote droplet transport. The present invention constructs a hygroscopic material with a hydrophilic-hydrophobic dual-functional (Janus) structure, which can achieve efficient moisture absorption and droplet aggregation, meeting the dehumidification needs of small areas; the system relies on the physical and chemical properties of the hygroscopic material itself to achieve dehumidification, with low energy consumption, energy saving and environmental protection; the optimized dehumidification process ensures that the hygroscopic material can be recycled multiple times without reducing its performance, effectively extending the life of the equipment and reducing the maintenance frequency; the system adopts a miniaturized design, which is suitable for distributed and small-area applications.

Description

Technical Field

[0001] The present invention belongs to the technical field of hygroscopic materials, and in particular relates to a hygroscopic material based on a polymer film, a preparation method thereof, and an application thereof. Background Art

[0002] In recent years, global humidity levels have fluctuated dramatically due to factors such as climate change. Many regions have experienced prolonged periods of high humidity, posing dual challenges to dehumidification and water resource management for industrial, agricultural, and residential facilities. Existing dehumidification and water collection technologies are primarily categorized into two main types: condensation dehumidification and desiccant dehumidification. Condensation dehumidification reduces air temperature, causing water vapor to condense into liquid water. These systems typically consist of a compressor refrigeration system, a heat exchanger, a water collection container, and a drainage system. The compressor refrigeration system utilizes a compressor and refrigerant to effectively lower the air temperature. The heat exchanger, either within the air conditioning circuit or as a standalone module, facilitates heat exchange between the air and the internal media of the equipment. Once moisture condenses, the water collection container and drainage system automatically collect the moisture through diversion for subsequent disposal. Desiccant dehumidification, on the other hand, primarily captures moisture from the air through physical or chemical adsorption. Common hygroscopic materials include silica gel, activated carbon, and composite hygroscopic materials. These materials are often structurally modified to form thin sheets, honeycomb structures, or fiber structures to increase their contact area with moisture in the air. Furthermore, functional coating technologies apply hydrophilic or super-hydrophilic coatings to the surface of hygroscopic materials to optimize the rate of water molecule adsorption and improve water collection efficiency. In practical applications, hygroscopic materials are often combined with environmental sensors to monitor humidity changes in real time. Once saturation is reached, the hygroscopic capacity is restored through natural drying or low-temperature regeneration, ensuring continuous and efficient dehumidification.

[0003] Existing dehumidification and water collection technology products are relatively mature in large-scale environments and industrial scenarios. They have stable structural designs and complete system functions, providing good technical support for remote monitoring, automatic control, and continuous operation. However, for the special needs of small-scale, high-humidity environments, the existing technology system has exposed three core flaws:

[0004] (1) High energy consumption and bulky size: Most devices using condensation dehumidification technology rely on high-power compressors and heat exchange systems, consuming a large amount of energy during the cooling process. The equipment is large in size and is not suitable for small areas or local high-humidity environments. In particular, in high-temperature environments, the condensation efficiency is reduced, further exacerbating the energy consumption problem.

[0005] (2) Hygroscopic material saturation and low regeneration efficiency: Existing hygroscopic materials quickly reach saturation in high humidity environments, and the regeneration process requires the use of high-energy external heat or other methods, resulting in insufficient continuous operation capacity of the equipment. This characteristic makes it difficult to ensure stability and economic benefits during long-term operation and cannot meet the needs of continuous dehumidification.

[0006] (3) Insufficient adaptability to microenvironments: The design concept of existing systems focuses on large-scale or centralized treatment. In small-scale and distributed scenarios, the development of equipment miniaturization and precise control technology lags behind, resulting in the lack of efficient water collection and fine-tuning functions. Traditional designs have failed to break through the bottleneck of micro-scale structure optimization, making it difficult to achieve local dehumidification results, which directly restricts the promotion and application of intelligent and automated management systems. In addition, the high cost of membrane separation technology lacks economic feasibility in small-scale scenarios, further highlighting the application limitations of existing technology systems.

[0007] To solve the above problems, the present invention proposes a hygroscopic material based on a polymer film, a preparation method and an application thereof. Summary of the Invention

[0008] The object of the present invention is to provide a hygroscopic material based on a polymer film and a preparation method and application thereof, in order to solve the problems raised in the above background technology.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] A hygroscopic material based on a polymer film comprises a hydrophilic-hydrophobic dual-functional structure constructed based on the polymer film, wherein the surface of the polymer film is subjected to plasma activation treatment to form an activated region, and a modified region is formed in a predetermined region through chemical adsorption and silanization reaction; the modified region contains hydrophilic groups and hydrophobic silane chains, and the hydrophilic layer forms hydrogen bonds with water molecules in the air through surface polar functional groups, thereby enhancing local moisture absorption capacity; in a saturated state, the surface condenses to form droplets, and self-driven sliding is achieved through the contact angle gradient provided by the hydrophobic side.

[0011] Furthermore, the hydrophilic groups in the modified region include silanol and amino groups.

[0012] A method for preparing the hygroscopic material according to the above-mentioned method comprises the following steps:

[0013] Raw material selection and pretreatment: Select polymer films with a static contact angle between 70° and 120°, perform plasma activation treatment, cut into fibers of predetermined size, and reserve predetermined modified areas;

[0014] Surface modification and Janus structure formation: Immersing the pretreated polymer membrane in a predetermined modified region in a modification solution for chemical adsorption and silanization reaction to form a hydrophilic-hydrophobic bifunctional structure rich in hydrophilic groups and hydrophobic silane chains; the modification solution contains tetraethoxysilane, 3-glycidoxypropylmethyltriethoxysilane, and bis(3-aminopropyl)-terminated polydimethylsiloxane;

[0015] Hydrolysis and condensation to form a film: The impregnated polymer film is placed under acidic conditions and subjected to hydrolysis and silane condensation reactions at room temperature to form a continuous and dense modified film;

[0016] Thermal annealing treatment: gently washing with deionized water to remove residual acid, and naturally air-drying, and then performing thermal annealing treatment to stabilize and solidify the surface modification layer structure to obtain a hygroscopic material.

[0017] Furthermore, the polymer film after activation treatment is cut into fibers with a width of 1 to 5 mm and a length of 2 to 10 cm, and half of the length (1 to 5 cm) is reserved as a predetermined modified area.

[0018] Furthermore, in the modified solution, the molar ratio of tetraethoxysilane, 3-glycidoxypropylmethyltriethoxysilane and bis(3-aminopropyl)-terminated polydimethylsiloxane is 10:1:1.

[0019] Furthermore, the hydrolysis and silane condensation reaction is carried out under hydrochloric acid conditions with a pH of 4, and the reaction time is 3 to 6 hours.

[0020] Furthermore, the thermal annealing treatment is performed at a temperature of 60° C. for 2 to 4 hours.

[0021] A use of the above-mentioned hygroscopic material in preparing a dehumidification system.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. Efficient Moisture Absorption and Collection: This invention creates a hygroscopic material with a hydrophilic-hydrophobic dual-functional (Janus) structure by surface-modifying a polymer membrane. Under high humidity conditions of 80-95% relative humidity, the modified regions of the material undergo localized silanization to form hydrophobic silane chains, retaining a large number of hydrophilic groups. The activated regions effectively reduce the sliding angle and contact angle hysteresis of water droplets, synergistically achieving the dual functions of rapid moisture capture and rapid droplet aggregation and roll-off, meeting the dehumidification needs of small areas.

[0024] 2. Low energy consumption, energy saving and environmental protection: The system relies on the physical and chemical properties of the hygroscopic material to achieve dehumidification. It does not require an external intelligent control unit, regeneration module or high-power equipment, which reduces the complexity and energy consumption of the system while reducing the impact on the environment.

[0025] 3. Continuous and stable recycling: The optimized dehumidification process ensures that the hygroscopic material can be recycled multiple times without loss of performance, which can ensure the long-term continuous and stable operation of the dehumidification process, effectively extending the life of the equipment and reducing maintenance frequency.

[0026] 4. Adaptable to distributed and small-area applications: The system adopts a miniaturized design. Compared with traditional large-volume dehumidification equipment, it has flexible deployment and low operating costs, providing reliable technical support for electronic product storage, precision instrument protection, environmental control and distributed micro-water resource utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Prepare a process flow chart for hygroscopic materials.

[0028] Figure 2 Static contact angle and sliding angle tests of hygroscopic materials before and after preparation.

[0029] Figure 3 It is a moisture absorption and water transport mechanism under high humidity.

[0030] Figure 4 Comparison of the water collection performance of various hygroscopic materials; a is a photo of the hygroscopic water collection process in a 90% RH (relative humidity) environment, and b is a comparison chart of the water collection efficiency of hygroscopic materials.

[0031] Figure 5 Schematic diagram of the overall system structure and water capture process.

[0032] Figure 6 These are microscope photographs and three-dimensional micromorphology images of the activated area and modified area of ​​the modified PET film in Example 1; wherein a is a microscope photograph and three-dimensional micromorphology image of the activated area, and b is a microscope photograph and three-dimensional micromorphology image of the modified area.

[0033] Figure 7 This is the moisture absorption and water collection process of the modified PET film in Example 1 under high humidity; where ad is the process in which the modified area captures water vapor and condenses and aggregates into droplets; ef is the process in which the activated area transports droplets; and il is the process in which the droplets absorb moisture again after falling - condense - aggregate - and transport.

[0034] Figure 8 The water collection efficiency statistics of 10 modified PET film samples in Example 1 under 90% RH (relative humidity) environment.

[0035] Figure 9 The water collection efficiency statistics of the modified PET film in Example 1 within 30 days.

[0036] Figure 10 The curve of the internal environmental humidity of the dryer in Example 1 changing with time. DETAILED DESCRIPTION

[0037] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0038] The present invention provides a method for preparing a hygroscopic material based on a polymer film, and the specific process is as follows ( Figure 1 ):

[0039] Step 1: Raw material selection and pretreatment;

[0040] Material selection and advantages: Commercially available polymer films with static contact angles between 70 and 120° are selected, such as polyethylene terephthalate (PET), polyvinyl chloride (PVC), polydimethylsiloxane (PDMS), polyethylene (PE), polymethyl methacrylate (PMMA), polypropylene (PP), polyamide (PA), polyimide (PI), polycarbonate (PC), polyphenylene sulfide (PPS), etc. These materials have the following advantages: (1) they are widely available and low-cost, making them suitable for large-scale production; (2) they are acid-resistant, alkali-resistant, and aging-resistant, and are not easily decomposed in the environment, ensuring chemical stability during long-term use; (3) they have high tensile and wear resistance, ensuring that the modified hygroscopic material is not easily broken or deformed under mechanical stress.

[0041] Pretreatment and Cutting: The polymer film is placed on the central sample holder of the plasma treatment chamber. After evacuation to 0.3-0.5 Torr, high-purity nitrogen is introduced and the pressure is stabilized at 0.3-0.8 Torr. A plasma glow discharge is initiated at 30-60 W for 60-180 s to uniformly generate reactive functional groups such as –OH, –COOH, or –NH2 on the film surface. This step not only facilitates chemical bonding and enhances spreading uniformity, but also reduces solution consumption during subsequent modification. Using standard cutting equipment, the polymer film is processed into fibers with a width of 1-5 mm and a length of 2-10 cm, leaving approximately 1-5 cm for the intended modification area.

[0042] Step 2: Surface modification and Janus structure formation;

[0043] Modification solution preparation: Tetraethoxysilane (TEOS), 3-glycidoxypropylmethyltriethoxysilane (TGOS), and bis(3-aminopropyl)-terminated polydimethylsiloxane (H2N–PDMS–NH2) were mixed in a molar ratio of 10:1:1 and stirred at room temperature for 24 hours to obtain a uniformly mixed modification solution. TEOS, as the primary film-forming precursor, provides the siloxane network and hydrophobicity; TGOS introduces epoxy groups to enhance adhesion to the substrate; and H2N–PDMS–NH2 contributes hydrophilic groups, improving the material's hygroscopicity.

[0044] Immersion process: The predetermined modified area of ​​the fibrous polymer membrane is immersed in the modification solution for 5 to 10 minutes, so that the silane precursor in the modification solution is chemically adsorbed on the surface of the polymer membrane, inducing a silanization reaction to form a hydrophilic-hydrophobic bifunctional (Janus) structure rich in hydrophilic groups (mainly derived from silanols generated by TEOS hydrolysis and amino groups of H2N–PDMS–NH2) and hydrophobic silane chains. The unmodified area remains in the activated treatment state.

[0045] Hydrolysis and condensation to form a membrane: The impregnated polymer membrane is placed in a sealed container containing hydrochloric acid (pH 4) for 3-6 hours at room temperature to undergo hydrolysis and silane condensation reactions. This process uses hydrochloric acid to catalyze the hydrolysis and condensation reactions, crosslinking and solidifying the surface silanization products into a continuous and dense modified film, providing a stable chemical foundation for subsequent water capture.

[0046] Thermal Annealing: After hydrolysis and condensation, the sample is gently rinsed with deionized water to remove residual acid and air-dried. The sample is then thermally annealed in a 60°C oven for 2-4 hours to produce the hygroscopic material. Rapid thermal annealing further stabilizes and solidifies the surface modification layer, effectively eliminating residual stress and ensuring a uniform and dense modified layer. This ensures that the hygroscopic material maintains efficient moisture absorption and water collection capabilities during long-term cyclic use.

[0047] Contact angle test: Taking PET film as an example, the static contact angle of its original surface is 71.9±0.7°. After the above preparation process, the modified PET film shows an obvious Janus structure ( Figure 2 ): The modified area exhibits hydrophobicity, and the static contact angle increases to 98.5±1.1°, which is conducive to the nucleation and aggregation of droplets; the static contact angle of the activated area only increases slightly, and still maintains hydrophilicity, which is 77.6±0.8°, but its dynamic wetting performance is significantly improved compared with the original surface, and its sliding angle decreases from 48.0° to 29.5°, and the contact angle hysteresis decreases from 21.0° to 8.2°, which significantly reduces the starting resistance of droplets in this area, thereby promoting the efficient flow and collection of aggregated droplets along the activated area.

[0048] The present invention further discloses the continuous water capture mechanism of the hygroscopic material in a high humidity environment, the water capture and water collection process of the hygroscopic material in a high humidity environment ( Figure 3 ) mainly depends on its surface dual-functional structure and physical geometry, as follows:

[0049] Water vapor capture and condensation: In high humidity environments, water vapor in the air is rapidly captured by the numerous hydrophilic groups (such as silanols and amino groups) on the surface of the modified region of the hygroscopic material (formed by fibrous polymer membranes treated with a modified solution, hydrolysis, and silane condensation) through van der Waals forces and hydrogen bonding. Within approximately 10 seconds, it condenses into numerous tiny droplets with diameters of 100 to 200 μm. Due to the hydrophobic silane structure in the modified region, these tiny droplets gradually aggregate into larger droplets.

[0050] Water droplet transport: The activated area of ​​the hygroscopic material (formed by plasma activation treatment of the polymer film) reduces the surface energy, presents a smaller sliding angle and contact angle hysteresis, which helps the droplets to slide freely on the surface. After the water droplets gradually aggregate along the surface of the hygroscopic material, under the action of gravity and surface tension, they quickly roll down the activated channel to the water collection channel to achieve continuous water collection. In addition, the narrower transport channel can further increase the contact angle between the water droplets and the polymer film, optimize the movement and transport effect of the droplets, and thus improve the overall water capture and water collection efficiency. The water collection process of some modified materials including PET, PVC, PE, PA, PI, PmmA and PP films in a 90% RH (relative humidity) environment is as follows Figure 4 As shown in Figure a. These hygroscopic materials all have excellent water collection and absorption capabilities, with water collection efficiencies ranging from 11.14 to 13.47 g·cm within 6 h. -2 ·h -1 ( Figure 4 Middle b).

[0051] Continuous water collection and seamless circulation mechanism: The hygroscopic material spontaneously absorbs, condenses, aggregates, and transports moisture, eliminating the need for an external intelligent control unit or regeneration module, reducing system complexity and energy consumption. This mechanism ensures that the hygroscopic material can continuously capture and transport moisture in persistent high-humidity environments, ensuring long-term, efficient operation.

[0052] The present invention provides a dehumidification system comprising a hygroscopic material based on a polymer membrane, which adopts the following integrated design ( Figure 5 ):

[0053] The dehumidification system mainly includes a high-humidity air inlet, an environmental pretreatment module (which integrates a filter, a noise reduction device and a ventilation control unit), a modified moisture absorption module, an activated area micron-level channel and a water collection container. The overall structure is arranged vertically, completing air treatment and moisture capture in sequence from top to bottom.

[0054] First, highly humid air (80-95% humidity) is introduced into the system through the top air inlet. It undergoes preliminary treatment in the environmental pretreatment module, which removes particulate matter, reduces airflow noise, and regulates air temperature and flow rate. The treated humid air then flows into a modified hygroscopic module, which utilizes a Janus-structured hygroscopic material. Its airflow-facing side is enriched with hydrophilic groups (such as silanols and amino groups) for efficient water adsorption, while the hydrophobic surface on the other side provides unidirectional water conduction and prevents backflow. Driven by gravity and surface energy differences, the adsorbed droplets migrate downward along the micron-scale channels of the activated area. During this movement, small droplets gradually merge into larger droplets, ultimately rolling down to a lower water collection container for continuous water collection and storage. This entire process utilizes air flow guidance, droplet merging, and a low sliding angle design to ensure efficient and continuous water capture.

[0055] Through the above-mentioned detailed preparation process and water capture process, the hygroscopic material not only achieves efficient dehumidification and moisture collection, but also reduces energy consumption and complexity with its simplified system structure, providing a new, economical and efficient solution for distributed dehumidification in high-humidity environments.

[0056] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0057] Example 1: Preparation and application of high-efficiency moisture-absorbing material based on PET film;

[0058] (1) Composition and preparation;

[0059] Raw material selection and pretreatment: A commercially available polyethylene terephthalate (PET) film with a thickness of approximately 100 μm was selected and activated for 3 minutes using a plasma surface treatment device. The activated PET film was then cut using a precision cutter to form fibers with a width of 1 mm and a length of 20 mm, leaving approximately 10 mm of length as the intended modification area.

[0060] Surface modification and Janus structure formation: The predetermined modified area (10 mm in length) of the pretreated fibrous PET film was immersed in a modification solution (TEOS, TGOS, H2N–PDMS–NH2, molar ratio 10:1:1) for 5 min. It was then placed in a closed desiccator containing hydrochloric acid (acidic conditions of pH 4) and reacted at room temperature for 4 h. After the reaction, the sample was washed with deionized water, air-dried, and annealed at 60 ° C for 3 h to obtain a hygroscopic material (i.e., modified PET film). Atomic force microscopy showed that the surface of the PET film was still flat and uniform after treatment, and the arithmetic mean roughness of the activated area and the modified area were 5.33 nm and 5.68 nm, respectively ( Figure 6In (a) and (b), the relatively low and uniform roughness provides a stable interface basis for the moisture absorption and water collection process, promoting the smooth occurrence of moisture absorption and water collection.

[0061] System Integration: Ten pre-prepared modified PET films were assembled side by side into dehumidifying plates, with spacing between the films controlled within a range of 0.5–1 mm. Furthermore, 5–10 dehumidifying plates were installed in a parallel arrangement within the dryer's dehumidification duct, with spacing of approximately 1 cm between plates to ensure uniform flow of moist air through each modified area and achieve adequate contact. The dehumidifying plates were installed at key locations along the inner wall and top ventilation section of the dehumidifying duct, and were equipped with built-in micro-fans (at a speed of 1–2 m / s) to enhance air flow. A dedicated water collection trough was located at the bottom of the duct to collect water droplets that fell from the dehumidifying plates after being captured and collected.

[0062] (2) Effects;

[0063] Moisture absorption and water collection performance: In an experimental environment with a relative humidity of 90%, a large number of tiny liquid droplets with a diameter of about 150 μm condensed on the surface of the modified PET film within 10 seconds. Subsequently, under the action of the hydrophobic silane structure in the modified area of ​​the material, the tiny droplets gradually merged into large droplets and quickly rolled down the micron-sized channels in the activated area to the water collection tank under the action of gravity ( Figure 7 (a~l).

[0064] Water collection efficiency test: Figure 8 As shown in Figure 2, under continuous high humidity conditions of 90% RH (relative humidity) for 1 h, all 10 modified PET film samples showed the ability to efficiently capture and continuously collect water. The water collection efficiency of sample 6 in the second test reached 10.98 g·cm -2 ·h -1 , which is the highest value among all test data.

[0065] Durability: As Figure 9 As shown in the figure, after 99 cycles of moisture absorption and natural drying tests within 30 days, the water collection efficiency of the hygroscopic material remained within a relatively stable range (9.01±0.31 g·cm -2 ·h -1 to 9.98±0.12 g·cm -2 ·h -1 ), with an overall fluctuation of less than 10%, which indicates that the material has good durability and recyclability.

[0066] An example of integrated application in electrical appliances: Desiccant plates are installed in the inner wall and top air ducts of the dryer. A built-in micro fan is used to promote internal air flow. When high-humidity air flows through the desiccant plates, moisture is quickly captured and collected in the water collection tank. Actual operation tests show that ( Figure 10), within 1 hour, the humidity inside the dryer decreased from the initial 95.6% RH to 64.1% RH, indicating that the desiccant plate effectively reduced the humidity inside the dryer, thereby helping to extend the service life of the equipment and improve sanitary conditions.

[0067] The above are only preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several variations and improvements can be made without departing from the concept of the present invention. These should also be regarded as the scope of protection of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A method for preparing a hygroscopic material based on a polymer film, characterized in that: The following steps are involved: Raw material selection and pretreatment: Select polymer films with a static contact angle between 70° and 120°, perform plasma activation treatment, cut into fibers of predetermined size, and reserve predetermined modified areas; Surface modification and Janus structure formation: Immersing the pretreated polymer membrane in a predetermined modified region in a modification solution for chemical adsorption and silanization reaction to form a hydrophilic-hydrophobic bifunctional structure rich in hydrophilic groups and hydrophobic silane chains; the modification solution contains tetraethoxysilane, 3-glycidoxypropylmethyltriethoxysilane, and bis(3-aminopropyl)-terminated polydimethylsiloxane; Hydrolysis and condensation to form a film: The impregnated polymer film is placed under acidic conditions and subjected to hydrolysis and silane condensation reactions at room temperature to form a continuous and dense modified film; Thermal annealing treatment: gently washing with deionized water to remove residual acid, and naturally air-drying, and then performing thermal annealing treatment to stabilize and solidify the surface modification layer structure to obtain a hygroscopic material.

2. The preparation method according to claim 1, characterized in that The polymer film after activation treatment is cut into fibers with a width of 1 to 5 mm and a length of 2 to 10 cm, and a length of 1 to 5 cm is reserved as a predetermined modified area.

3. The preparation method according to claim 1, characterized in that In the modified solution, the molar ratio of tetraethoxysilane, 3-glycidyloxypropylmethyltriethoxysilane and bis(3-aminopropyl)-terminated polydimethylsiloxane is 10:1:

1.

4. The preparation method according to claim 1, characterized in that The hydrolysis and silane condensation reaction is carried out under hydrochloric acid conditions with a pH of 4, and the reaction time is 3 to 6 hours.

5. The preparation method according to claim 1, characterized in that The thermal annealing treatment is performed at a temperature of 60° C. for 2 to 4 hours.

6. A hygroscopic material based on a polymer film obtained by the preparation method according to any one of claims 1 to 5, characterized in that: The invention comprises a hydrophilic-hydrophobic dual-functional structure constructed based on a polymer film, wherein the surface of the polymer film is treated by plasma activation to form an activated area, and a modified area is formed in a predetermined area by chemical adsorption and silanization reaction; The modified region contains hydrophilic groups and hydrophobic silane chains for capturing water vapor and promoting its condensation into droplets. The activated region is used to reduce the sliding angle and contact angle hysteresis of the droplets, thereby promoting the transport of the droplets.

7. The hygroscopic material according to claim 6, characterized in that The hydrophilic groups in the modified region include silanol and amino groups.

8. Use of the hygroscopic material according to claim 6 or 7 in preparing a dehumidification system.

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