A system and method for continuous liquid replenishment controllable condensation densification of a nanoporous material

Abstract

The application discloses a kind of nano-porous material continuous liquid supplementing controllable condensation densification systems, it is related to nano-porous material preparation field, including feeding cavity, boiling cavity, process cavity and connecting above three cavity pipeline and control system, wherein, feeding cavity is used to store liquid working medium and is isolated from outside atmosphere in the process of liquid supplementing, the bottom of the cavity of feeding cavity is connected with the bottom of boiling cavity by pipeline and valve;Boiling cavity is used as independent clean steam generation source, and the top of cavity is connected with the steam inlet of process cavity;Process cavity is the place for nano material densification reaction.The whole system receives corresponding signal and controls each module by an integrated central controller, realizes automatic process and closed loop control.The application also discloses a method for realizing nano-porous material continuous liquid supplementing controllable condensation densification using the system.The application realizes the continuity and automation of process, the precision and digitization of process, the uniformity and high repeatability of result.

Description

Technical Field

[0001] This invention relates to the field of nanoporous material preparation, and in particular to a system and method for continuous liquid replenishment and controllable condensation densification of nanoporous materials. Background Technology

[0002] Nanoporous materials, due to their high specific surface area, tunable pore structure, and excellent physicochemical properties, have broad application prospects in cutting-edge fields such as catalysis, adsorption separation, energy storage, sensing, and biomedicine. These materials typically possess a multi-level pore structure ranging from microscopic to macroscopic, and the full expression of their macroscopic properties often depends on the precise control of the overall density, porosity, and pore connectivity of the material. Therefore, densification treatment using physical or chemical methods to optimize their mechanical strength, mass transfer pathways, or electrical / thermal transport networks has become an important research direction in material post-processing.

[0003] Among numerous densification methods, wet methods, especially solvent vapor condensation, have attracted attention due to their gentle action, effective maintenance of the material's main framework, and ease of operation. The typical principle of this method is to expose the nanoporous material to a condensable solvent vapor environment (such as acetone or isopropanol). The vapor condenses within the complex pore network of the material, generating significant capillary forces that drive the pore walls or constituent units (such as nanowires and sheets) to approach and rearrange themselves, thus achieving overall structural densification.

[0004] However, current steam condensation densification technology is mostly regarded as a basic laboratory treatment method. Its process and control methods are relatively rudimentary, with a series of inherent limitations that severely restrict its development towards precision, controllability, and repeatability in advanced manufacturing. The shortcomings of existing technologies are mainly reflected in the following aspects: First, the process environment and process control are extremely rudimentary. Existing methods are typically carried out under normal atmospheric pressure, such as simply placing the material above an open container filled with boiling solvent, or spraying the liquid working fluid directly onto the material surface. This method cannot eliminate the presence of ubiquitous non-condensable gases (such as air and nitrogen) in the environment. These gas molecules occupy pore spaces, hindering effective diffusion and uniform condensation of vapor, resulting in uneven densification and even gradient structures. Simultaneously, the vapor generation temperature, saturation, and supply rate, as well as the temperature of the material itself, cannot be independently, stably, and precisely controlled. This leaves key process drivers—such as vapor supersaturation and heat flux density at the condensation interface—in an uncontrollable random state, leading to poor repeatability and difficulty in reproducing the process results.

[0005] Secondly, there is a lack of system capabilities for decoupling and synergistic control of multi-physics parameters. The densification effect is essentially a macroscopic manifestation of the physical process of steam condensation within a complex porous medium. Its rate and uniformity directly depend on the complex coupling of multiple factors, including steam partial pressure, internal temperature gradient (subcooling), steam flux, and pore geometry. Current technologies involve these parameters in an open and uncontrollable environment, making independent measurement and precise adjustment impossible. For example, it is difficult to independently and continuously adjust the material's subcooling to study its effects while maintaining a specific system pressure, leading to a blurred process window, an inability to establish a quantitative relationship between "process parameters, material structure, and final properties," and poor designability of material properties.

[0006] Finally, the discontinuous operation mode makes it difficult to meet the demands of large-scale and automated production. Existing equipment mostly operates on a simple batch processing mode for single samples. When the processing medium is depleted, the process must be interrupted, and the system manually refilled. This process not only completely destroys the established microenvironment, introducing new contamination and batch-to-batch variations, but also forces the entire process to be interrupted, making continuous operation with no breaks possible. This discrete operation mode, reliant on manual intervention, is severely incompatible with the automation and continuity requirements of industrial production.

[0007] In summary, existing steam densification technologies, when dealing with objects with complex internal structures such as nanoporous materials, are limited by their extensive environmental control, lack of key parameter regulation capabilities, and discontinuous operation mode, making it difficult to achieve precise control over the densification process.

[0008] Therefore, those skilled in the art are dedicated to developing a system and method for continuous liquid replenishment and controllable condensation densification of nanoporous materials. This new densification system and method can create and maintain a stable and clean process environment, achieve independent and coordinated control of core process parameters, and support continuous operation. It is the key to promoting this technology from empirical laboratory processing to programmable advanced manufacturing and has important practical significance for expanding the high-end applications of nanoporous materials. Summary of the Invention

[0009] In view of the aforementioned shortcomings of the prior art, the technical problem to be solved by the present invention is the discontinuous process and poor process stability and repeatability caused by the inability to precisely control the steam source in existing methods. Furthermore, it solves the problems of uncontrollable condensation process and poor densification uniformity.

[0010] To achieve the above objectives, this invention provides a system for continuous liquid replenishment and controllable condensation densification of nanoporous materials, comprising a feeding chamber, a boiling chamber, a process chamber, and pipelines and a control system connecting the three chambers. The feeding chamber stores the liquid working fluid and isolates it from the external atmosphere during replenishment. The bottom of the feeding chamber is connected to the bottom of the boiling chamber via pipelines and valves, enabling continuous liquid replenishment under dynamic sealing without interrupting the process. The boiling chamber serves as an independent, clean steam source, including a heating and temperature control module and equipped with a thermocouple. The top of the cavity is connected to the steam inlet of the process chamber, which is the site for the densification reaction of nanomaterials. The cavity is filled with steam working fluid, and an independent temperature-controlled sample stage is provided at the top for loading the sample to be densified. The cavity is connected to the outside through a pipeline equipped with a pressure regulating valve and a vacuum pump. The bottom of the cavity is equipped with a drain port and a drain shut-off valve. The entire system receives signals from various thermocouples and pressure sensors through an integrated central controller, and controls the heating and temperature control module, the sample stage temperature control module, various valves and the vacuum pump to achieve automated process and closed-loop control.

[0011] Furthermore, the feeding chamber includes a feeding chamber body that stores liquid working fluid. The side wall is provided with a feeding chamber observation window for observing the internal liquid level. The top is provided with an injection port and a shut-off valve, and an exhaust port and a shut-off valve. The bottom of the feeding chamber body is connected to a liquid working fluid connecting valve and to the bottom of the boiling chamber via a pipeline.

[0012] Furthermore, the boiling chamber includes a boiling chamber body, the bottom of which is connected to the feeding chamber through the liquid working fluid connecting valve. The chamber is equipped with an immersion heater and a temperature control module, and is fitted with a liquid working fluid temperature measuring thermocouple and a steam working fluid temperature measuring thermocouple. The top of the chamber is connected to the steam inlet of the process chamber through a steam working fluid flow and pressure control module.

[0013] Furthermore, the sample stage of the process chamber includes a sample stage body with a temperature control module, mechanical and electrical interfaces required for assembly, and a sample to be densified for loading. The sample stage body is controlled by resistance heating, ceramic semiconductor temperature control, or liquid working fluid flow temperature control. A process chamber vapor temperature measuring thermocouple is installed near the sample stage, and a process chamber observation window is provided on the side wall of the chamber for observing the condensation.

[0014] This invention also provides a method for continuous liquid replenishment and controllable condensation densification of nanoporous materials, using the system for continuous liquid replenishment and controllable condensation densification of nanoporous materials as described above, the method comprising the following steps: Step 1: System initialization and sample loading; Step 2: Establish the process vacuum environment; Step 3: Isolation-based continuous fluid replacement procedure; Step 4: Multi-parameter collaborative densification process; Step 5: Process completion and sample removal.

[0015] Further, step 1 specifically involves confirming that all valves are closed, opening the process chamber, fixing the sample to be densified on the independent temperature-controlled sample stage, and closing and locking the process chamber door.

[0016] Further, step 2 specifically involves turning on the vacuum pump, sequentially opening the steam working fluid flow and pressure control module and the pressure regulating valve, both to their maximum opening, starting the vacuum pump to evacuate the boiling chamber and process chamber, and closing the pressure regulating valve after the pressure has stabilized and dropped below 1.0 Pa; at this time, the system maintains a high vacuum, the steam working fluid flow and pressure control module remains open, and the liquid working fluid connecting valve, drain port and drain shut-off valve remain closed.

[0017] Further, step 3 specifically involves maintaining the vacuum in the boiling chamber and the process chamber while opening the injection port and shut-off valve, and the exhaust port and shut-off valve of the feeding chamber to inject liquid working medium until the liquid fills the observation window of the feeding chamber. The liquid working medium is one or more of water, isopropanol, ethanol, ethylene glycol, and diethyl ether. The liquid working medium connecting valve is slowly opened, and the liquid working medium flows into the boiling chamber under the action of pressure difference. At the same time, liquid is continuously replenished to the feeding chamber to maintain its liquid level and prevent air from entering. When the liquid level in the boiling chamber reaches a preset height and the liquid levels in both chambers are stable, the injection port and shut-off valve, the exhaust port and shut-off valve, and the liquid working medium connecting valve of the feeding chamber are closed in sequence to complete the isolation-type liquid replenishment. The preset height of the liquid level in the boiling chamber is set to submerge the heater.

[0018] Further, step 4 specifically involves first activating the immersion heater and temperature control module of the boiling chamber to heat the liquid working fluid to 5-15°C above the saturated boiling temperature of the working fluid under the process chamber pressure, and monitoring the steam state through the liquid working fluid temperature measuring thermocouple and the steam working fluid temperature measuring thermocouple; subsequently, coordinating the setting of condensation conditions: activating the temperature control function of the independent temperature-controlled sample stage to stabilize the sample temperature at the target value to control the subcooling ΔT, with the subcooling ΔT adjustable within the range of 5-50 K; adjusting the pressure regulating valve to precisely stabilize the pressure in the process chamber at the target value of 0.1 hPa-100 kPa; adjusting the steam working fluid flow rate and pressure control module to control the steam flux; after the parameters stabilize, starting the process timing, the steam undergoes controllable condensation on the sample surface, generating capillary force to drive the densification of carbon nanotubes; during this process, the process is monitored through the process chamber observation window or integrated sensor, and the process is determined to end when the predetermined time or the change stabilizes.

[0019] Further, step 5 specifically involves shutting down the immersion heater, temperature control module, and steam working fluid flow and pressure control module; opening the pressure regulating valve to depressurize the system to atmospheric pressure; opening the process chamber to remove the sample; and then cycling through steps 2 and 4. The replenishment operation in step 3 is only repeated when the working fluid in the feeding chamber is insufficient.

[0020] Traditional steam densification devices require manual replenishment by breaking the vacuum and opening the chambers after the working fluid is depleted, leading to process interruptions, environmental contamination, and hindering long-term, automated, and stable operation. This invention proposes an isolated, continuous replenishment method for the feeding chamber. Utilizing the principle of communicating vessels, liquid working fluid is replenished from the outside of the system while maintaining a completely sealed process chamber, preventing ambient gases from entering the boiling chamber and process chamber. Based on the principles of communicating vessels and pressure balance, each chamber operates independently when the replenishment valve is closed. When replenishment is needed, the working fluid is forced into a second chamber via valve control, utilizing the pressure difference between the replenishment chamber (at normal pressure) and the boiling chamber (low pressure), achieving fluid transport under "dynamic sealing." This ensures process continuity.

[0021] Existing methods for steam supply and control are relatively crude. For example, methods that directly heat the beaker cannot precisely control the steam temperature, saturation, and supply rate, resulting in large fluctuations in steam state, which is a major source of process noise. This invention addresses this by implementing independent and controlled clean steam generation and dual-point monitoring within the boiling chamber: an independent chamber equipped with a precision heater and immersion-type liquid temperature thermocouples and steam space thermocouples to monitor the steam generation status in real time, achieving independent temperature control and status monitoring. Physically isolating the steam source from the process chamber allows for independent optimization of boiling conditions. Dual thermocouple monitoring directly obtains the steam superheat (steam temperature - boiling point at current pressure), thereby accurately predicting the steam dryness and stability, providing a constant and pure steam source for the process chamber.

[0022] Traditional methods rely on natural condensation in the environment, and key parameters such as supercooling, ambient pressure, and vapor flux cannot be independently controlled, leading to uneven densification levels across different batches and even different locations within the same sample. The uncontrollable condensation process results in poor uniformity of the final nanoporous material densification. This invention decouples the core driving conditions of the condensation process—vapor partial pressure (driving force) and sample surface supercooling (condensation kinetics)—into independent, precisely controllable engineering parameters (pressure P, temperature T). By controlling this parameter combination (P, T, flow rate), the heat flux density and mass flow rate at the condensation interface can be directly controlled, thereby precisely controlling the rate and magnitude of capillary force generation and achieving multi-physics field synergistic regulation.

[0023] Traditional methods cannot determine the densification process in real time, typically relying on fixed time intervals or experience, which can easily lead to under-processing or over-processing. Process endpoint determination also depends on experience and lacks in-situ feedback. This invention proposes an integrated in-situ monitoring scheme using an observation window and optional sensors: the observation window allows for direct monitoring of liquid accumulation; further integration with laser displacement gauges, optical interferometers, or resistance monitoring probes can provide real-time feedback on changes in sample thickness or electrical properties. This establishes a correlation between macroscopic, measurable physical changes during densification (such as sample column diameter or bottom shrinkage / deflection; reduction in array resistance, etc.) and the microscopic degree of densification, using this signal as a direct basis for process closed-loop control or endpoint determination.

[0024] Compared with the prior art, the present invention has significant technical advantages: (1) It supports long-term, uninterrupted densification processes, laying the foundation for industrial production. It ensures a pure process environment: it completely avoids non-condensable gases and impurities introduced by liquid replenishment, ensuring that the starting conditions of each process cycle are consistent. It has been upgraded from being limited to single-processing (approximately hours) to long-term continuous operation (up to tens or even hundreds of hours) only limited by the capacity of the raw material tank.

[0025] (2) It reduces the fluctuation of core process variables (steam supply) from the source, provides a stable and controllable steam source, makes the input conditions of the entire densification process highly repeatable, and improves the stability and reliability of the process.

[0026] (3) By setting process curves (such as pressure program and temperature program), the densification rate and final density can be precisely controlled, realizing the leap from "qualitative processing" to "quantitative manufacturing", which greatly improves the consistency and performance designability of the product, and ultimately ensures the precise programming control of the densification process.

[0027] (4) Eliminate reliance on operator experience and improve automation level. By adjusting process parameters through real-time feedback, better process window control can be achieved, and new process phenomena may be discovered, enabling intelligent judgment and closed-loop control of the process endpoint.

[0028] (5) The system adopts a three-chamber modular design of "feeding-evaporation-process". In actual production, multiple "evaporation-process" modules can be connected in parallel according to capacity requirements and supplied by a central feeding system, easily achieving linear capacity scaling. Flammable and explosive organic working fluids (such as acetone) are sealed in independent chambers and remotely monitored through observation windows, greatly reducing the risk of direct exposure. The clear step-by-step operation logic of replenishing liquid, vacuuming, and starting the process also reduces the requirements for operator experience.

[0029] The application scope of this invention includes, but is not limited to, arrays with high aspect ratio (1:100 or more) and small diameter (d≤5um) formed by materials such as carbon nanotube arrays, silicon nanowires, boron nitride nanotubes, carbon fibers, polyurethane, PEEK (polyether ether ketone), PTFE (polytetrafluoroethylene), PE (polyethylene), PP (polypropylene), PVC (polyvinyl chloride), and PI (polyimide).

[0030] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of a nanoporous material continuous replenishment controllable condensation densification system according to a preferred embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of an independent temperature-controlled sample stage according to a preferred embodiment of the present invention; Wherein: 100-Feeding chamber; 101-Feeding chamber body; 102-Liquid working fluid; 103-Feeding chamber observation window; 104-Injection port and shut-off valve; 105-Exhaust port and shut-off valve; 200-Boiling chamber; 201-Boiling chamber body; 202-Immersion heater and temperature control module; 203-Liquid working fluid temperature measuring thermocouple; 204-Steam working fluid temperature measuring thermocouple; 205- 206-Liquid working fluid connection valve; 300-Steam working fluid flow and pressure control module; 301-Process chamber; 302-Steam working fluid; 303-Process chamber observation window; 304-Independent temperature-controlled sample stage; 3041-Sample stage mechanical interface; 3042-Sample stage electrical interface; 3043-Sample stage body; 3044-Sample to be densified; 305-Process chamber steam temperature measuring thermocouple; 306-Pressure regulating valve; 307-Vacuum pump; 308-Drain port and drain shut-off valve. Detailed Implementation

[0032] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0033] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0034] Example 1: Continuous Liquid Supply and Controllable Condensation Densification System for Nanoporous Materials

[0035] like Figure 1 As shown, the system for continuous liquid replenishment and controllable condensation densification of nanoporous materials provided by the present invention mainly includes: a feeding chamber 100, a boiling chamber 200, a process chamber 300, and pipelines and a control system connecting each chamber. The feeding chamber 100 is used to store the liquid working fluid and isolate it from the external atmosphere during the replenishment process. It comprises a feeding chamber body 101 containing a liquid working fluid 102. An observation window 103 is provided on the side wall for observing the internal liquid level. The top is equipped with an injection port and a shut-off valve 104, and an exhaust port and a shut-off valve 105. The bottom of the chamber is connected to a liquid working fluid connecting valve 205 via pipelines and is connected to the bottom of the boiling chamber 200. The boiling chamber 200, serving as an independent and clean steam source, comprises a boiling chamber body 201. The bottom of this chamber is connected to the feeding chamber 100 via the liquid working fluid connecting valve 205. An immersion heater and temperature control module 202 are installed within the chamber, along with a liquid working fluid temperature measuring thermocouple 203 and a steam working fluid temperature measuring thermocouple 204. The top of the chamber is connected to the steam inlet of the process chamber 300 via a steam working fluid flow and pressure control module 206. The process chamber 300 is the site for the densification reaction of nanomaterials. It comprises a process chamber body 301 filled with steam working fluid 302, and an independently temperature-controlled sample stage 304 is located at its top. Figure 2 As shown, the sample stage includes a sample stage body 3043 with temperature control, a mechanical interface 3041 and an electrical interface 3042 for assembly, and a sample 3044 for loading for densification. A process chamber vapor temperature measuring thermocouple 305 is installed near the sample stage. A process chamber observation window 303 is provided on the side wall of the chamber for observing condensation. The chamber is connected to the outside via a pipeline equipped with a pressure regulating valve 306 and a vacuum pump 307. A drain port and a drain shut-off valve 308 are provided at the bottom of the chamber. The entire system receives signals from various thermocouples and pressure sensors through an integrated central controller (not shown in the figure) and controls the heating and temperature control module 202, the sample stage temperature control module 3043, various valves, and the vacuum pump 307 to achieve automated process and closed-loop control.

[0036] Example 2: A method for continuous liquid replenishment and controllable condensation densification of nanoporous materials

[0037] In this embodiment, the nanoporous material is a vertically arranged array of carbon nanotubes, and the densified organic liquid working fluid is acetone.

[0038] Step 1: System Initialization and Sample Loading. Confirm that all valves 104, 105, 205, 206, 306, and 308 are closed. Open the process chamber 300, fix the sample 3044 to be densified onto the independent temperature-controlled sample stage 304, and close and lock the chamber door.

[0039] Step 2: Establish the process vacuum environment. Turn on the vacuum pump 307, and sequentially open the steam working fluid flow and pressure control module 206 (open to maximum) and the pressure regulating valve 306. Start the vacuum pump 307 to evacuate the boiling chamber 200 and the process chamber 300. After the pressure stabilizes and drops below 1.0 Pa, close the pressure regulating valve 306. At this time, the system maintains a high vacuum below 1 Pa, the steam working fluid flow and pressure control module 206 remains open, and the liquid working fluid connection valve 205, the drain port, and the drain shut-off valve 308 remain closed.

[0040] Step 3: Isolation-type continuous liquid replenishment operation. While maintaining vacuum in the boiling chamber and process chamber, open the injection port and shut-off valve 104 and the vent port and shut-off valve 105 of the feeding chamber 100, injecting acetone liquid until the liquid fills the observation window 103 of the feeding chamber. Slowly open the liquid working fluid connection valve 205, and acetone flows into the boiling chamber 200 under the action of pressure difference. At the same time, continuously replenish the feeding chamber 100 to maintain its liquid level and prevent air from entering. When the liquid level in the boiling chamber 200 reaches the preset height (e.g., immersing the heater) and the liquid levels in both chambers are stable, close the injection port and shut-off valve 104, the vent port and shut-off valve 105, and the liquid working fluid connection valve 205 in sequence to complete the isolation-type liquid replenishment.

[0041] Step 4: Multi-parameter Collaborative Densification Process. First, the immersion heater and temperature control module 202 of the boiling chamber 200 are activated to heat acetone to 61°C, 5°C above the boiling temperature of 56°C. The steam state is monitored by the liquid working fluid thermocouple 203 and the steam working fluid thermocouple 204. Next, condensation conditions are collaboratively set: the temperature control function of the independent temperature-controlled sample stage 304 is activated to stabilize the sample temperature at the target value of 11°C to control the subcooling ΔT, which is 50 K; the pressure regulating valve 306 is adjusted to precisely stabilize the pressure in the process chamber 300 at the target value of 5 kPa; and the steam working fluid flow and pressure control module 206 is adjusted to control the steam flux. After the parameters stabilize, the process timing begins. The steam undergoes controllable condensation on the sample surface, generating capillary force that drives the densification of carbon nanotubes. During this process, the observation window 303 of the process chamber or the integrated sensor is used to monitor the process. The process is considered complete when the predetermined time or the changes stabilize.

[0042] Step 5: Process Completion and Sample Removal. Turn off the immersion heater, temperature control module 202, and steam working fluid flow and pressure control module 206. Open the pressure regulating valve 306 to depressurize the system to atmospheric pressure. Open the process chamber 300 and remove the sample. Subsequent processes can be repeated from steps 2 and 4, with step 3 only needing to be repeated for replenishment if the liquid working fluid in the feeding chamber 100 is insufficient.

[0043] Example 3: A method for continuous liquid replenishment and controllable condensation densification of nanoporous materials

[0044] In this embodiment, the nanoporous material is a vertically arranged array of carbon nanotubes, and the densified organic liquid working fluid is acetone.

[0045] Step 1: System Initialization and Sample Loading. Confirm that all valves 104, 105, 205, 206, 306, and 308 are closed. Open the process chamber 300, fix the sample 3044 to be densified onto the independent temperature-controlled sample stage 304, and close and lock the chamber door.

[0046] Step 2: Establish the process vacuum environment. Turn on the vacuum pump 307, and sequentially open the steam working fluid flow and pressure control module 206 (open to maximum) and the pressure regulating valve 306. Start the vacuum pump 307 to evacuate the boiling chamber 200 and the process chamber 300. After the pressure stabilizes and drops below 1.0 Pa, close the pressure regulating valve 306. At this time, the system maintains a high vacuum below 1 Pa, the steam working fluid flow and pressure control module 206 remains open, and the liquid working fluid connection valve 205, the drain port, and the drain shut-off valve 308 remain closed.

[0047] Step 3: Isolation-type continuous liquid replenishment operation. While maintaining vacuum in the boiling chamber and process chamber, open the injection port and shut-off valve 104 and the vent port and shut-off valve 105 of the feeding chamber 100, injecting acetone liquid until the liquid fills the observation window 103 of the feeding chamber. Slowly open the liquid working fluid connection valve 205, and acetone flows into the boiling chamber 200 under the action of pressure difference. At the same time, continuously replenish the feeding chamber 100 to maintain its liquid level and prevent air from entering. When the liquid level in the boiling chamber 200 reaches the preset height (e.g., immersing the heater) and the liquid levels in both chambers are stable, close the injection port and shut-off valve 104, the vent port and shut-off valve 105, and the liquid working fluid connection valve 205 in sequence to complete the isolation-type liquid replenishment.

[0048] Step 4: Multi-parameter Collaborative Densification Process. First, the immersion heater and temperature control module 202 of the boiling chamber 200 are activated to heat acetone to 71°C, 15°C above the preset boiling temperature of 56°C. The steam state is monitored by the liquid working fluid thermocouple 203 and the steam working fluid thermocouple 204. Next, condensation conditions are collaboratively set: the temperature control function of the independent temperature-controlled sample stage 304 is activated to stabilize the sample temperature at the target value of 66°C to control the subcooling ΔT, which is 5 K; the pressure regulating valve 306 is adjusted to precisely stabilize the pressure in the process chamber 300 at the target value of 100 kPa; and the steam working fluid flow and pressure control module 206 is adjusted to control the steam flux. After the parameters stabilize, the process timing begins. The steam undergoes controllable condensation on the sample surface, generating capillary force that drives the densification of carbon nanotubes. During this process, the observation window 303 of the process chamber or the integrated sensor is used to monitor the process. The process is considered complete when the predetermined time or the changes stabilize.

[0049] Step 5: Process Completion and Sample Removal. Turn off the immersion heater, temperature control module 202, and steam working fluid flow and pressure control module 206. Open the pressure regulating valve 306 to depressurize the system to atmospheric pressure. Open the process chamber 300 and remove the sample. Subsequent processes can be repeated from steps 2 and 4, with step 3 only needing to be repeated for replenishment if the liquid working fluid in the feeding chamber 100 is insufficient.

[0050] Example 4: A method for continuous liquid replenishment and controllable condensation densification of nanoporous materials

[0051] In this embodiment, the nanoporous material is vertically arranged silicon nanowires, and the densified organic liquid working fluid is ethylene glycol.

[0052] Step 1: System Initialization and Sample Loading. Confirm that all valves 104, 105, 205, 206, 306, and 308 are closed. Open the process chamber 300, fix the sample 3044 to be densified onto the independent temperature-controlled sample stage 304, and close and lock the chamber door.

[0053] Step 2: Establish the process vacuum environment. Turn on the vacuum pump 307, and sequentially open the steam working fluid flow and pressure control module 206 (open to maximum) and the pressure regulating valve 306. Start the vacuum pump 307 to evacuate the boiling chamber 200 and the process chamber 300. After the pressure stabilizes and drops below 1.0 Pa, close the pressure regulating valve 306. At this time, the system maintains a high vacuum below 1 Pa, the steam working fluid flow and pressure control module 206 remains open, and the liquid working fluid connection valve 205, the drain port, and the drain shut-off valve 308 remain closed.

[0054] Step 3: Isolation-type continuous liquid replenishment operation. While maintaining vacuum in the boiling chamber and process chamber, open the injection port and shut-off valve 104 and the vent port and shut-off valve 105 of the feeding chamber 100, injecting ethylene glycol liquid until the observation window 103 of the feeding chamber is filled. Slowly open the liquid working fluid connection valve 205, and under the action of pressure difference, ethylene glycol flows into the boiling chamber 200. At the same time, continuously replenish the feeding chamber 100 to maintain its liquid level and prevent air from entering. When the liquid level in the boiling chamber 200 reaches the preset height (e.g., immersing the heater) and the liquid levels in both chambers are stable, close the injection port and shut-off valve 104, the vent port and shut-off valve 105, and the liquid working fluid connection valve 205 in sequence to complete the isolation-type liquid replenishment.

[0055] Step 4: Multi-parameter Collaborative Densification Process. First, the immersion heater and temperature control module 202 of the boiling chamber 200 are activated to heat ethylene glycol to 212.3℃, 15℃ above the preset boiling temperature of 197.3℃. The steam state is monitored by the liquid working fluid thermocouple 203 and the steam working fluid thermocouple 204. Next, condensation conditions are collaboratively set: the temperature control function of the independent temperature-controlled sample stage 304 is activated to stabilize the sample temperature at the target value of 207.3℃ to control the subcooling ΔT, which is 5 K; the pressure regulating valve 306 is adjusted to precisely stabilize the pressure in the process chamber 300 at the target value of 5 kPa; and the steam working fluid flow and pressure control module 206 is adjusted to control the steam flux. After the parameters stabilize, the process timing begins. The steam undergoes controllable condensation on the sample surface, generating capillary force that drives the densification of silicon nanowires. During this process, the observation window 303 of the process chamber or the integrated sensor is used to monitor the process. The process is considered complete when the predetermined time or the changes stabilize.

[0056] Step 5: Process Completion and Sample Removal. Turn off the immersion heater, temperature control module 202, and steam working fluid flow and pressure control module 206. Open the pressure regulating valve 306 to depressurize the system to atmospheric pressure. Open the process chamber 300 and remove the sample. Subsequent processes can be repeated from steps 2 and 4, with step 3 only needing to be repeated for replenishment if the liquid working fluid in the feeding chamber 100 is insufficient.

[0057] The continuous liquid replenishment and controllable condensation densification system and method for nanoporous materials of the present invention, through precise engineering design, transforms laboratory processes into a stable and controllable industrial technology prototype, with the following specific advantages: 1. Achieving continuous and automated processes: Traditional methods require manual opening of chambers, liquid addition, and vacuuming for each batch, resulting in low efficiency and poor consistency. This system's core design of "isolated continuous liquid replenishment" makes it possible to replenish materials while maintaining an absolutely stable process environment. This lays the foundation for a fully automated, unattended continuous production line in the future, representing a crucial step towards industrialization.

[0058] 2. Refinement and Digitalization of the Process: Existing technologies heavily rely on operator experience to control densification results. This invention addresses this by independently controlling the steam temperature (T). v ), sample temperature (T) s The three core parameters—condensation rate, system pressure (P)—are decoupled for the first time from the physical quantities affecting condensation rate and capillary force into independently programmable engineering variables. This means that the densification process can be transformed from an "art" into a set of "digital recipes" that can be precisely reproduced and optimized, such as "treating for t minutes at a subcooling of ΔT=20K under pressure P1."

[0059] 3. Ensuring uniformity and high repeatability of results: By eliminating contamination introduced by replenishment, providing a stable steam source, and achieving precise control of process parameters, this system ensures a high degree of consistency in product performance across different locations within the same batch and between different batches. This is a fundamental and crucial requirement for any serious industrial production.

[0060] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A system for continuous liquid replenishment and controllable condensation densification of nanoporous materials, characterized in that, The system includes a feeding chamber, a boiling chamber, a process chamber, and piping and a control system connecting these three chambers. The feeding chamber stores the liquid working fluid and isolates it from the external atmosphere during replenishment. The bottom of the feeding chamber is connected to the bottom of the boiling chamber via piping and valves, enabling continuous replenishment under dynamic sealing without interrupting the process. The boiling chamber serves as an independent, clean steam source, containing heating and temperature control modules and equipped with thermocouples. The top of the boiling chamber is connected to the steam inlet of the process chamber. The process chamber is where the nanomaterial densification reaction takes place. It is filled with steam working fluid and has an independent temperature-controlled sample stage at the top for loading samples to be densified. The chamber is connected to the outside via a pipe equipped with a pressure regulating valve and a vacuum pump. The bottom of the chamber has a drain port and a drain shut-off valve. The entire system receives signals from the thermocouples and pressure sensors through an integrated central controller, controlling the heating and temperature control modules, the sample stage temperature control module, the valves, and the vacuum pump to achieve automated process and closed-loop control.

2. The system for continuous liquid replenishment and controllable condensation densification of nanoporous materials as described in claim 1, wherein the feeding chamber includes a feeding chamber body, which stores liquid working fluid, and a feeding chamber observation window is provided on the side wall for observing the internal liquid level. The top is provided with an injection port and a shut-off valve, and an exhaust port and a shut-off valve. The bottom of the feeding chamber body is connected to a liquid working fluid connecting valve through a pipeline and is connected to the bottom of the boiling chamber.

3. The system for continuous liquid replenishment and controllable condensation densification of nanoporous materials as described in claim 1, wherein the boiling chamber includes a boiling chamber body, the bottom of which is connected to the feeding chamber through the liquid working fluid connecting valve, the chamber is provided with an immersion heater and a temperature control module, and is equipped with a liquid working fluid temperature measuring thermocouple and a steam working fluid temperature measuring thermocouple, and the top of the chamber is connected to the steam inlet of the process chamber through a steam working fluid flow and pressure control module.

4. The system for continuous liquid replenishment and controllable condensation densification of nanoporous materials as described in claim 1, wherein the sample stage of the process chamber includes a sample stage body with a temperature control module, mechanical and electrical interfaces required for assembly, and a sample to be densified for loading; the sample stage body is controlled by resistance heating, ceramic semiconductor temperature control, or liquid working fluid flow temperature control; a process chamber vapor temperature measuring thermocouple is installed near the sample stage, and a process chamber observation window is provided on the side wall of the chamber for observing the condensation.

5. A method for continuous liquid replenishment and controllable condensation densification of nanoporous materials, using the system for continuous liquid replenishment and controllable condensation densification of nanoporous materials as described in claims 1-4, the method comprising the following steps: Step 1: System initialization and sample loading; Step 2: Establish the process vacuum environment; Step 3: Isolation-based continuous fluid replacement procedure; Step 4: Multi-parameter collaborative densification process; Step 5: Process completion and sample removal.

6. A method for continuous liquid replenishment and controllable condensation densification of nanoporous materials, wherein step 1 specifically involves confirming that all valves are closed, opening the process chamber, fixing the sample to be densified on the independent temperature-controlled sample stage, and closing and locking the process chamber door.

7. A method for continuous liquid replenishment and controllable condensation densification of nanoporous materials, wherein step 2 specifically involves turning on the vacuum pump, sequentially opening the steam working fluid flow and pressure control module and the pressure regulating valve, both opened to their maximum, starting the vacuum pump to evacuate the boiling chamber and process chamber, and closing the pressure regulating valve after the pressure stabilizes and drops below 1.0 Pa; at this time, the system maintains a high vacuum, the steam working fluid flow and pressure control module remains open, and the liquid working fluid connecting valve, drain port and drain shut-off valve remain closed.

8. A method for continuous liquid replenishment and controllable condensation densification of nanoporous materials, wherein step 3 specifically involves, while maintaining a vacuum in the boiling chamber and the process chamber, opening the injection port and shut-off valve and the exhaust port and shut-off valve of the feeding chamber, injecting liquid working fluid into the chamber until the liquid fills the observation window of the feeding chamber, wherein the liquid working fluid is one or more of water, isopropanol, ethanol, ethylene glycol, and diethyl ether; slowly opening the liquid working fluid connecting valve, allowing the liquid working fluid to flow into the boiling chamber under pressure differential, while continuously replenishing the feeding chamber to maintain its liquid level and prevent air from entering; when the liquid level in the boiling chamber reaches a preset height and the liquid levels in both chambers are stable, sequentially closing the injection port and shut-off valve, the exhaust port and shut-off valve, and the liquid working fluid connecting valve of the feeding chamber to complete the isolation-type liquid replenishment; the preset height of the liquid level in the boiling chamber is set to submerge the heater.

9. A method for continuous liquid replenishment and controllable condensation densification of nanoporous materials, wherein step 4 specifically involves first activating the immersion heater and temperature control module of the boiling chamber to heat the liquid working fluid to 5-15 °C above the saturated boiling temperature of the working fluid under the process chamber pressure, and monitoring the steam state through liquid working fluid temperature measuring thermocouples and steam working fluid temperature measuring thermocouples; subsequently, coordinating the setting of condensation conditions: activating the temperature control function of the independent temperature-controlled sample stage to stabilize the sample temperature at the target value to control the subcooling ΔT, the adjustment range of subcooling ΔT being 5-50 K; adjusting the pressure regulating valve to precisely stabilize the pressure in the process chamber at the target value of 0.1 hPa-100 kPa; adjusting the steam working fluid flow rate and pressure control module to control the steam flux; after the parameters stabilize, starting the process timing, the steam undergoes controllable condensation on the sample surface to generate capillary force, driving the densification of carbon nanotubes; during this process, the process is monitored through the process chamber observation window or integrated sensor, and the process is determined to end when the predetermined time or the change stabilizes.

10. A method for continuous liquid replenishment and controllable condensation densification of nanoporous materials, wherein step 5 specifically involves shutting down the immersion heater, temperature control module, and steam working fluid flow and pressure control module; opening the pressure regulating valve to depressurize the system to atmospheric pressure; opening the process chamber to remove the sample; and the subsequent process is carried out in a cycle from steps 2 and 4, with the liquid replenishment operation in step 3 only repeated when the working fluid in the feeding chamber is insufficient.

Images