Preparation method of extremely low-temperature-resistant sensing materials that can be used for polar exploration

Abstract

The present invention discloses a method for preparing an extremely low-temperature-resistant sensing material that can be used for polar exploration. The present invention comprises: the preparation of an extremely low-temperature-resistant organic hydrogel precursor solution; the preparation of a biomimetic adhesive; the preparation of an extremely low-temperature-resistant organic hydrogel; and the preparation of an extremely low-temperature-resistant sensing material. The present invention introduces a binary solvent to form strong hydrogen bonds between free water molecules to inhibit the crystallization of water molecules at low temperatures. The sensing material matrix is ​​constructed by an interpenetrating network composed of highly entangled polymer chains and cellulose-metal ion chelation. Dynamic hydrophobic association cross-linking points are introduced to effectively dissipate energy during the deformation process of the sensing material. The addition of a biomimetic adhesive promotes the formation of microphase separation domains in the gel. The present invention overcomes the trade-off problem between adhesion, conductivity, temperature resistance and mechanics of the sensing material under the synergistic effect of the interpenetrating network-hydrophobic association-hydrogen bond-chain entanglement, and realizes wireless encrypted transmission of distress signals at an ultra-low temperature of 78°C through a wearable human-computer interaction mechanism.

Description

Technical Field

[0001] The present invention relates to the field of flexible sensors, and in particular to a method for preparing an extremely low-temperature-resistant sensing material for polar exploration. Background Art

[0002] As representative of Earth's extreme environments, the polar regions have never ceased human exploration. This is crucial for understanding Earth's climate, geological structure, and biological adaptability. Furthermore, exploration of the polar regions helps assess resource reserves, development potential, and sustainable utilization. However, extreme climates increase the safety risks of exploration. Therefore, there is an urgent need for sensing materials that can operate at extremely low temperatures.

[0003] Conductive hydrogels are widely used as sensing materials due to their good conformability, flexibility and high conductivity. However, the operating temperature range of hydrogel-based flexible sensors is relatively narrow and they still face great challenges at low temperatures. At low temperatures, the freezing of water in the gel will cause delayed response of flexible sensors, impaired signal acquisition accuracy, and loss of mechanical properties. At present, some antifreeze gel-based flexible sensing materials have been developed to achieve signal acquisition at low temperatures, but most of them show inherent trade-offs due to some key material parameters (such as stretchability, operating temperature, conductivity, etc.), and cannot balance antifreeze performance, stretchability and sensing performance at extreme low temperatures. To the best of our knowledge, there has been no previous report on human-computer interaction sensing materials based on organic hydrogels that are extremely resistant to low temperatures and can be used for polar exploration and emergency rescue. Therefore, there is an urgent need to design a new flexible sensing material for polar exploration to achieve i) real-time monitoring of explorers' physiological movement status, timely detection of physical abnormalities and taking measures; ii) timely sending and transmitting distress signals when explorers encounter danger; iii) application in robots to make them more intelligent, improve their interactive skills and timely transmit various information when performing dangerous tasks such as deep diving and rescue. Summary of the Invention

[0004] This invention aims to address the problem of traditional sensing materials being susceptible to failure at extremely low temperatures. To overcome the shortcomings of existing technologies, it provides a method for preparing an extremely low-temperature-resistant sensing material suitable for polar exploration. While achieving extreme low-temperature resistance, this material can also be used for human-computer interaction and emergency rescue during polar exploration.

[0005] To solve the technical problem, the solution of the present invention is as follows:

[0006] (1) Preparation of extremely low-temperature resistant organohydrogel precursor solution:

[0007] Solution A: Prepare a binary solvent by mixing 100-200 parts by weight of an organic solvent α and 100-200 parts by weight of water.

[0008] Solution B: Dissolve 50-70 parts by weight of a hydrophilic monomer, 0.0001-0.001 parts by weight of a crosslinker, and 0.1-0.2 parts by weight of an initiator in 200-400 parts by weight of binary solution A and stir at room temperature for 5 minutes. Subsequently, add 0.1-0.2 parts by weight of an emulsifier and 0.1-0.2 parts by weight of a hydrophobic monomer, and sonicate using a cell disrupter for 2-10 minutes. Finally, add 0.1-0.2 parts by weight of cellulose and 0.1-0.2 parts by weight of an inorganic salt. Stir at room temperature for 1 hour to obtain an antifreeze organohydrogel precursor solution.

[0009] (2) Preparation of biomimetic adhesive:

[0010] Solution C: Dissolve 1-2 parts by weight of a polyphenol compound in 20-30 parts by weight of solvent water.

[0011] Solution D: Dissolve 1-2 parts by weight of branched polyethyleneimine in 20-30 parts by weight of solvent water.

[0012] Solution D is added to solution C, mixed, and then the pH is adjusted to 4-5 with an acidic solution to obtain a biomimetic adhesive.

[0013] (3) Preparation of extremely low-temperature resistant organic hydrogels:

[0014] 10-100 parts by weight of the antifreeze organohydrogel precursor solution prepared in step (1) and 10-100 parts by weight of the biomimetic adhesive prepared in step (2) are mixed evenly, poured into a polytetrafluoroethylene mold, and cured under ultraviolet light for 1 hour to obtain an extremely low-temperature-resistant organohydrogel.

[0015] (4) Preparation of extremely low temperature resistant sensing materials:

[0016] The extremely low-temperature-resistant organic hydrogel prepared in step (3) was used to prepare a 30×8×1 mm rectangular sheet, which was then connected to flexible silver electrodes at both ends and encapsulated with VHB tape to obtain an extremely low-temperature-resistant sensing material.

[0017] In the present invention, the organic solvent α refers to one or more of ethylene glycol, glycerol, dimethyl sulfoxide, and ethanol.

[0018] In the present invention, the hydrophilic monomer refers to one or more of acrylamide, acrylic acid, and polyvinyl alcohol.

[0019] In the present invention, the cross-linking agent refers to one or more of polyethylene glycol diacrylate and N,N-methylenebisacrylamide.

[0020] In the present invention, the initiator is one of 2,2'-azo(2-methylpropylamidine) dihydrochloride, ammonium persulfate, potassium persulfate, and azobisisobutyronitrile.

[0021] In the present invention, the emulsifier refers to one or more of fatty alcohol polyoxyethylene ether, cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, and sodium lauryl sulfate.

[0022] In the present invention, the hydrophobic monomer refers to one or more of octadecyl methacrylate, lauryl methacrylate, trifluoroethyl methacrylate, pentafluoropropyl methacrylate, perfluorohexylethyl methacrylate, and perfluorooctylethyl acrylate.

[0023] In the present invention, the inorganic salt refers to one or more of calcium chloride dihydrate, anhydrous calcium chloride, magnesium chloride, sodium chloride and potassium chloride.

[0024] In the present invention, the polyphenol compound refers to one or more of dopamine, tannic acid, catechol, gallic acid, and catechin.

[0025] In the present invention, the weight average molecular weight of the branched polyethyleneimine is 10,000-25,000.

[0026] In the present invention, the acidic solution refers to one or more of dilute hydrochloric acid and dilute sulfuric acid.

[0027] The present invention further provides an application of the extremely low-temperature-resistant sensing material prepared by the aforementioned method for polar exploration, comprising the following steps:

[0028] A wireless Bluetooth transmission module, designed to connect to the sensing material, was developed. It includes a microcontroller, an analog-to-digital converter, a removable power supply input interface, an external regulated power supply input interface, and a signal input interface. Motion or physiological signals from the input are converted into relevant voltammograms by the wireless Bluetooth transmission module and transmitted to a smart device. A Morse code-based communication mechanism was developed based on the wireless Bluetooth transmission module, encoding the 26 English letters using different combinations of "·" and "-" symbols. The SOS code was defined as "···---···," and a small 30° and a large 90° bend of the finger were encoded as "·" and "-," respectively. The sensing material was attached to the finger joints of the robotic hand, and silver wires were used as the electrode layer. The electrodes were sealed with copper foil tape on both sides and connected in series with the Bluetooth transmission module. To simulate polar temperatures at -78°C, a 1V voltage is applied through a mobile regulated power supply. The bending signal of the robot's fingers is modulated by the microcontroller of the Bluetooth transmission module and converted into a corresponding current signal through an analog-to-digital converter. The signal is then wirelessly transmitted to a dedicated mobile application "Bluetooth Debugger" on a mobile phone or computer. This mobile application can visualize the current and realize the wireless transmission of the "SOS" distress signal through the bending arc of the fingers.

[0029] Description of the invention principle:

[0030] Conductive hydrogels are widely used in flexible sensing materials due to their good conformability, flexibility and high conductivity. However, the operating temperature range of hydrogel-based sensing materials is relatively narrow and they still face great challenges at low temperatures. At low temperatures, the freezing of water in the hydrogel will cause delayed response of the sensing material, impaired signal acquisition accuracy, and loss of mechanical properties. At present, some antifreeze gel-based sensing materials have been developed to achieve signal acquisition at low temperatures, but most of them cannot combine antifreeze performance, stretching and pressure sensing performance in a wide temperature range due to some key material parameters (such as stretchability, operating temperature, conductivity, etc.). To the best of our knowledge, there has been no previous report on human-computer interaction sensing materials based on organic hydrogels that are extremely resistant to low temperatures and can be used for polar exploration and emergency rescue. Therefore, there is an urgent need to design a new flexible sensing material for polar exploration to achieve 1) real-time monitoring of explorers' physiological movement status in severe winter, timely detection of physical abnormalities and taking measures; 2) timely sending and transmitting distress signals when explorers encounter danger; 3) application to robots to make them more intelligent, improve their interactive skills and timely transmit various information when performing dangerous tasks such as deep diving and rescue.

[0031] Based on the needs of polar exploration, the inventor synthesized a flexible sensing material designed for polar explorers and robots that can operate at extremely low temperatures (-78°C). Inspired by the byssal mucus of cold-resistant organisms such as wood frogs and mussels, an extremely antifreeze interpenetrating network organic hydrogel was synthesized, combining four strategies: (1) highly entangled cross-linked hydrophilic chains as the first network and an antifreeze binary solvent as the dispersion medium; (2) the introduction of a dynamic hydrophobic association structure; (3) cellulose chelated with inorganic salt metal ions as the second network; and (4) the addition of a branched polyethyleneimine-polyphenol complex biomimetic adhesive, which forms strong intermolecular interactions with the entangled chains and the interpenetrating network through multiple hydrogen bonds, promoting the formation of microphase separation domains. The hydrogen bond-chain entanglement synergistic supramolecular interaction improves the mechanical properties of the organic hydrogel. The prepared organic hydrogel has high ionic conductivity, high elongation at break, skin-like softness, sensitive tensile sensing properties and pressure sensing properties, and can realize real-time and efficient monitoring and identification of multi-source signals such as motion-physiology-voice-pressure under ambient conditions. In addition, thanks to the synergistic effect of inorganic salts and glycerol-water binary solvents, the organic hydrogel exhibits extreme low-temperature tolerance. Flexible sensing materials based on organic hydrogels can perform intelligent gesture recognition at low temperatures, and can still monitor human movements and identify various pressures even at -78°C. The sensing material of the present invention is combined with a wearable human-computer interaction mechanism, which can realize wireless encrypted transmission of distress signals and help information at ultra-low temperatures of -78°C. It can also be used for the transmission of various daily information, providing safety for explorers in polar regions, and at the same time is conducive to the exploration and development of more intelligent and humane polar robots when performing deep diving and rescue missions.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The four preparation strategies combined in this invention overcome the trade-off problem among the adhesion, conductivity, temperature resistance and mechanical properties of traditional sensing materials through hydrogen bond-chain entanglement and synergistic supramolecular interaction.

[0034] (2) The sensing material produced by the present invention is extremely resistant to low temperatures and can monitor human movement and identify various pressures even at -78°C. Combined with a wearable human-machine interaction mechanism, it provides safety protection for explorers in polar regions and facilitates the development of more intelligent and humane polar robots when performing deep-sea diving and rescue missions. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the mechanism of the extremely low-temperature-resistant sensing material of the present invention that can be used for polar exploration. DETAILED DESCRIPTION

[0036] The present invention will be further described in detail below with reference to specific examples and comparative examples. The examples may help professionals in this field to understand the present invention more comprehensively, but they do not limit the present invention in any way.

[0037] like Figure 1 As shown, this invention, based on research on the cryoresistant wood frog, imparts extreme low-temperature adaptability to the sensing material through the synergistic effect of a binary solvent. Highly entangled polymer chains and cellulose chelated with metal ions form an interpenetrating network, with dynamic hydrophobic associations serving as physical crosslinks. Finally, a biomimetic binder is introduced to form strong intermolecular interactions with the entangled chains and the interpenetrating network, resulting in microphase-separated domains. Hydrogen bonding and chain entanglement synergistic supramolecular interactions enhance the mechanical properties of the organohydrogel, overcoming the trade-offs between adhesion, conductivity, thermal resistance, and mechanical properties typically encountered in traditional sensing materials. This enables real-time, efficient monitoring and recognition of multiple signals, including motion, physiology, speech, and pressure, even at ultra-low temperatures. The device can monitor human motion and recognize various pressures and gestures, even at ultra-low temperatures. A communication mechanism developed based on Morse code, combined with wearable human-machine interaction, enables polar exploration in all seasons, enabling wireless, encrypted transmission of distress signals and messages even at temperatures as low as -78°C. This technology also promotes the development of more intelligent and user-friendly polar robots for deep-sea diving and rescue missions.

[0038] Example 1

[0039] The preparation and use methods of an extremely low-temperature-resistant sensing material that can be used for polar exploration involved in this embodiment are as follows:

[0040] (1) Preparation of extremely low-temperature resistant organohydrogel precursor solution:

[0041] Solution A: Prepare a binary solvent by mixing 100 parts by weight of ethylene glycol and 100 parts by weight of water.

[0042] Solution B: Dissolve 50 parts by weight of polyvinyl alcohol, 0.0001 parts by weight of polyethylene glycol diacrylate, and 0.1 parts by weight of ammonium persulfate in 200 parts by weight of binary solution A and stir at room temperature for 5 minutes. Subsequently, add 0.1 parts by weight of sodium lauryl sulfate and 0.1 parts by weight of perfluorohexylethyl methacrylate, and sonicate using a cell disrupter for 3 minutes. Finally, add 0.1 parts by weight of cellulose and 0.1 parts by weight of anhydrous calcium chloride. Stir at room temperature for 1 hour to obtain an antifreeze organohydrogel precursor solution.

[0043] (2) Preparation of biomimetic adhesive:

[0044] Solution C: Dissolve 1 part by weight of dopamine in 20-30 parts by weight of solvent water.

[0045] Solution D: Dissolve 1 part by weight of branched polyethyleneimine with a weight-average molecular weight of 10,000 in 20-30 parts by weight of solvent water.

[0046] Solution D was added to solution C, and after mixing, the pH was adjusted to 4.2 with a dilute hydrochloric acid solution to obtain a biomimetic adhesive.

[0047] (3) Preparation of extremely low-temperature resistant organic hydrogels:

[0048] Take 10 parts by weight of the antifreeze organohydrogel precursor solution prepared in step (1) and 10 parts by weight of the biomimetic adhesive prepared in step (2), mix them evenly, pour them into a polyfluoroethylene mold, and cure them under ultraviolet light for 1 hour to obtain an extremely low-temperature resistant organohydrogel.

[0049] (4) Preparation of extremely low temperature resistant sensing materials:

[0050] The extremely low-temperature-resistant organic hydrogel prepared in step (3) was used to prepare a 30×8×1 mm rectangular sheet, which was then connected to flexible silver electrodes at both ends and encapsulated with VHB tape to obtain an extremely low-temperature-resistant sensing material.

[0051] A wireless Bluetooth transmission module, designed to connect to the sensing material, was developed. It includes a removable power input interface, an external regulated power input interface, and a signal input interface. The module converts motion or physiological signals from the input into a corresponding voltammogram and transmits it to a smart device. Based on this transmission module, a Morse code-based communication mechanism was developed, encoding the 26 English letters using various combinations of "·" and "-" symbols (SOS is encoded as "···---···," and small finger bends (30°) and large finger bends (90°) are encoded as "·" and "-," respectively). The sensing material was attached to the finger joints of a robotic hand. Silver wires were used as electrodes, sealed on both sides with copper foil tape, and connected in series with the Bluetooth transmission module. Simulating polar temperatures, a 1V voltage was applied from a removable regulated power supply at -78°C. The finger bend signal was modulated by the Bluetooth transmission module's microcontroller, converted into a corresponding current signal by an analog-to-digital converter, and then wirelessly transmitted to a dedicated "Bluetooth Debugger" mobile app on a mobile phone or computer. The mobile application can visualize the changes in electric current and realize the wireless transmission of the "SOS" distress signal by bending the finger.

[0052] Example 2

[0053] The preparation and use methods of an extremely low-temperature-resistant sensing material that can be used for polar exploration involved in this embodiment are as follows:

[0054] (1) Preparation of extremely low-temperature resistant organohydrogel precursor solution:

[0055] Solution A: 150 parts by weight of glycerol and 100 parts by weight of water were prepared into a binary solvent.

[0056] Solution B: Dissolve 60 parts by weight of acrylic acid, 0.0005 parts by weight of N,N-methylenebisacryloyl, and 0.15 parts by weight of potassium persulfate in 300 parts by weight of binary solution A and stir at room temperature for 5 minutes. Subsequently, add 0.15 parts by weight of hexadecyltrimethylammonium bromide and 0.15 parts by weight of lauryl methacrylate, and sonicate for 5 minutes using a cell disrupter. Finally, add 0.15 parts by weight of cellulose and 0.15 parts by weight of magnesium chloride. Stir at room temperature for 1 hour to obtain the antifreeze organohydrogel precursor solution.

[0057] (2) Preparation of biomimetic adhesive:

[0058] Solution C: Dissolve 2 parts by weight of tannic acid in 25 parts by weight of solvent water.

[0059] Solution D: 2 parts by weight of branched polyethyleneimine with a weight-average molecular weight of 15,000 was dissolved in 25 parts by weight of solvent water.

[0060] Solution D was added to solution C, and after mixing, the pH was adjusted to 4.8 with a dilute sulfuric acid solution to obtain a biomimetic adhesive.

[0061] (3) Preparation of extremely low-temperature resistant organic hydrogels:

[0062] Take 100 parts by weight of the antifreeze organohydrogel precursor solution prepared in step (1) and 50 parts by weight of the biomimetic adhesive prepared in step (2), mix them evenly, pour them into a polyfluoroethylene mold, and cure them under ultraviolet light for 1 hour to obtain an extremely low-temperature resistant organohydrogel.

[0063] (4) Preparation of extremely low temperature resistant sensing materials:

[0064] The extremely low-temperature-resistant organic hydrogel prepared in step (3) was used to prepare a 30×8×1 mm rectangular sheet, which was then connected to flexible silver electrodes at both ends and encapsulated with VHB tape to obtain an extremely low-temperature-resistant sensing material.

[0065] A wireless Bluetooth transmission module, designed to connect to the sensing material, was developed. It includes a removable power input interface, an external regulated power input interface, and a signal input interface. The module converts motion or physiological signals from the input into a corresponding voltammogram and transmits it to a smart device. Based on this transmission module, a Morse code-based communication mechanism was developed, encoding the 26 English letters using various combinations of "·" and "-" symbols (SOS is encoded as "···---···," and small finger bends (30°) and large finger bends (90°) are encoded as "·" and "-," respectively). The sensing material was attached to the finger joints of a robotic hand. Silver wires were used as electrodes, sealed on both sides with copper foil tape, and connected in series with the Bluetooth transmission module. Simulating polar temperatures, a 1V voltage was applied from a removable regulated power supply at -78°C. The finger bend signal was modulated by the Bluetooth transmission module's microcontroller, converted into a corresponding current signal by an analog-to-digital converter, and then wirelessly transmitted to a dedicated "Bluetooth Debugger" mobile app on a mobile phone or computer. The mobile application can visualize the changes in electric current and realize the wireless transmission of the "SOS" distress signal by bending the finger.

[0066] Example 3

[0067] The preparation and use methods of an extremely low-temperature-resistant sensing material that can be used for polar exploration involved in this embodiment are as follows:

[0068] (1) Preparation of extremely low-temperature resistant organohydrogel precursor solution:

[0069] Solution A: 200 parts by weight of dimethyl sulfoxide and 100 parts by weight of water were prepared into a binary solvent.

[0070] Solution B: Dissolve 70 parts by weight of acrylamide, 0.001 parts by weight of N,N-methylenebisacrylamide, and 0.2 parts by weight of 2,2'-azo(2-methylpropylamidine) dihydrochloride in 400 parts by weight of binary solution A and stir at room temperature for 5 minutes. Subsequently, add 0.2 parts by weight of hexadecyltrimethylammonium chloride and 0.2 parts by weight of octadecyl methacrylate, and sonicate for 8 minutes using a cell disrupter. Finally, add 0.2 parts by weight of cellulose and 0.2 parts by weight of calcium chloride dihydrate, and stir at room temperature for 1 hour to obtain an antifreeze organohydrogel precursor solution.

[0071] (2) Preparation of biomimetic adhesive:

[0072] Solution C: Dissolve 2 parts by weight of catechol in 30 parts by weight of solvent water.

[0073] Solution D: 2 parts by weight of branched polyethyleneimine with a weight-average molecular weight of 25,000 was dissolved in 30 parts by weight of solvent water.

[0074] Solution D was added to solution C, and after mixing, the pH was adjusted to 5 with a dilute hydrochloric acid solution to obtain a biomimetic adhesive.

[0075] (3) Preparation of extremely low-temperature resistant organic hydrogels:

[0076] Take 100 parts by weight of the antifreeze organohydrogel precursor solution prepared in step (1) and 30 parts by weight of the biomimetic adhesive prepared in step (2), mix them evenly, pour them into a polyfluoroethylene mold, and cure them under ultraviolet light for 1 hour to obtain an extremely low-temperature-resistant organohydrogel.

[0077] (4) Preparation of extremely low temperature resistant sensing materials:

[0078] The extremely low-temperature-resistant organic hydrogel prepared in step (3) was used to prepare a 30×8×1 mm rectangular sheet, which was then connected to flexible silver electrodes at both ends and encapsulated with VHB tape to obtain an extremely low-temperature-resistant sensing material.

[0079] A wireless Bluetooth transmission module, designed to connect to the sensing material, was developed. It includes a removable power input interface, an external regulated power input interface, and a signal input interface. The module converts motion or physiological signals from the input into a corresponding voltammogram and transmits it to a smart device. Based on this transmission module, a Morse code-based communication mechanism was developed, encoding the 26 English letters using various combinations of "·" and "-" symbols (SOS is encoded as "···---···," and small finger bends (30°) and large finger bends (90°) are encoded as "·" and "-," respectively). The sensing material was attached to the finger joints of a robotic hand. Silver wires were used as electrodes, sealed on both sides with copper foil tape, and connected in series with the Bluetooth transmission module. Simulating polar temperatures, a 1V voltage was applied from a removable regulated power supply at -78°C. The finger bend signal was modulated by the Bluetooth transmission module's microcontroller, converted into a corresponding current signal by an analog-to-digital converter, and then wirelessly transmitted to a dedicated "Bluetooth Debugger" mobile app on a mobile phone or computer. The mobile application can visualize the changes in electric current and realize the wireless transmission of the "SOS" distress signal by bending the finger.

[0080] Example 4

[0081] The preparation and use methods of an extremely low-temperature-resistant sensing material that can be used for polar exploration involved in this embodiment are as follows:

[0082] (1) Preparation of extremely low-temperature resistant organohydrogel precursor solution:

[0083] Solution A: 100 parts by weight of glycerol and 200 parts by weight of water were prepared into a binary solvent.

[0084] Solution B: Dissolve 65 parts by weight of polyvinyl alcohol, 0.0004 parts by weight of N,N-methylenebisacrylamide, 0.0004 parts by weight of polyethylene glycol diacrylate, and 0.2 parts by weight of ammonium persulfate in 250 parts by weight of binary solution A and stir at room temperature for 5 minutes. Subsequently, add 0.18 parts by weight of fatty alcohol polyoxyethylene ether and 0.18 parts by weight of perfluorooctyl ethyl acrylate, and sonicate for 10 minutes using a cell disrupter. Finally, add 0.18 parts by weight of cellulose and 0.18 parts by weight of potassium chloride, and stir at room temperature for 1 hour to obtain an antifreeze organohydrogel precursor solution.

[0085] (2) Preparation of biomimetic adhesive:

[0086] Solution C: Dissolve 1.8 parts by weight of gallic acid in 20-30 parts by weight of solvent water.

[0087] Solution D: 1.8 parts by weight of branched polyethyleneimine with a weight-average molecular weight of 25,000 was dissolved in 30 parts by weight of solvent water.

[0088] Solution D was added to solution C, and after mixing, the pH was adjusted to 4 with a dilute hydrochloric acid solution to obtain a biomimetic adhesive.

[0089] (3) Preparation of extremely low-temperature resistant organic hydrogels:

[0090] Take 100 parts by weight of the antifreeze organohydrogel precursor solution prepared in step (1) and 40 parts by weight of the biomimetic adhesive prepared in step (2), mix them evenly, pour them into a polyfluoroethylene mold, and cure them under ultraviolet light for 1 hour to obtain an extremely low-temperature-resistant organohydrogel.

[0091] (4) Preparation of extremely low temperature resistant sensing materials:

[0092] The extremely low-temperature-resistant organic hydrogel prepared in step (3) was used to prepare a 30×8×1 mm rectangular sheet, which was then connected to flexible silver electrodes at both ends and encapsulated with VHB tape to obtain an extremely low-temperature-resistant sensing material.

[0093] A wireless Bluetooth transmission module, designed to connect to the sensing material, was developed. It includes a removable power input interface, an external regulated power input interface, and a signal input interface. The module converts motion or physiological signals from the input into a corresponding voltammogram and transmits it to a smart device. Based on this transmission module, a Morse code-based communication mechanism was developed, encoding the 26 English letters using various combinations of "·" and "-" symbols (SOS is encoded as "···---···," and small finger bends (30°) and large finger bends (90°) are encoded as "·" and "-," respectively). The sensing material was attached to the finger joints of a robotic hand. Silver wires were used as electrodes, sealed on both sides with copper foil tape, and connected in series with the Bluetooth transmission module. Simulating polar temperatures, a 1V voltage was applied from a removable regulated power supply at -78°C. The finger bend signal was modulated by the Bluetooth transmission module's microcontroller, converted into a corresponding current signal by an analog-to-digital converter, and then wirelessly transmitted to a dedicated "Bluetooth Debugger" mobile app on a mobile phone or computer. The mobile application can visualize the changes in electric current and realize the wireless transmission of the "SOS" distress signal by bending the finger.

[0094] Example 5

[0095] The preparation and use methods of an extremely low-temperature-resistant sensing material that can be used for polar exploration involved in this embodiment are as follows:

[0096] (1) Preparation of extremely low-temperature resistant organohydrogel precursor solution:

[0097] Solution A: 150 parts by weight of glycerol and 150 parts by weight of water were prepared into a binary solvent.

[0098] Solution B: Dissolve 65 parts by weight of acrylamide, 0.0008 parts by weight of N,N-methylenebisacrylamide, and 0.2 parts by weight of potassium persulfate in 350 parts by weight of binary solution A and stir at room temperature for 5 minutes. Subsequently, add 0.15 parts by weight of sodium lauryl sulfate and 0.1 parts by weight of lauryl methacrylate, and sonicate for 6 minutes using a cell disrupter. Finally, add 0.15 parts by weight of cellulose and 0.15 parts by weight of potassium chloride. Stir at room temperature for 1 hour to obtain an antifreeze organohydrogel precursor solution.

[0099] (2) Preparation of biomimetic adhesive:

[0100] Solution C: Dissolve 1 part by weight of tannic acid in 25 parts by weight of solvent water.

[0101] Solution D: 1 part by weight of branched polyethyleneimine with a weight-average molecular weight of 20,000 was dissolved in 25 parts by weight of solvent water.

[0102] Solution D is added to solution C, mixed, and then the pH is adjusted to 4 with an acidic solution to obtain a biomimetic adhesive.

[0103] (3) Preparation of extremely low-temperature resistant organic hydrogels:

[0104] Take 100 parts by weight of the antifreeze organohydrogel precursor solution prepared in step (1) and 10 parts by weight of the biomimetic adhesive prepared in step (2), mix them evenly, pour them into a polyfluoroethylene mold, and cure them under ultraviolet light for 1 hour to obtain an extremely low-temperature-resistant organohydrogel.

[0105] (4) Preparation of extremely low temperature resistant sensing materials:

[0106] The extremely low-temperature-resistant organic hydrogel prepared in step (3) was used to prepare a 30×8×1 mm rectangular sheet, which was then connected to flexible silver electrodes at both ends and encapsulated with VHB tape to obtain an extremely low-temperature-resistant sensing material.

[0107] A wireless Bluetooth transmission module, designed to connect to the sensing material, was developed. It includes a removable power input interface, an external regulated power input interface, and a signal input interface. The module converts motion or physiological signals from the input into a corresponding voltammogram and transmits it to a smart device. Based on this transmission module, a Morse code-based communication mechanism was developed, encoding the 26 English letters using various combinations of "·" and "-" symbols (SOS is encoded as "···---···," and small finger bends (30°) and large finger bends (90°) are encoded as "·" and "-," respectively). The sensing material was attached to the finger joints of a robotic hand. Silver wires were used as electrodes, sealed on both sides with copper foil tape, and connected in series with the Bluetooth transmission module. Simulating polar temperatures, a 1V voltage was applied from a removable regulated power supply at -78°C. The finger bend signal was modulated by the Bluetooth transmission module's microcontroller, converted into a corresponding current signal by an analog-to-digital converter, and then wirelessly transmitted to a dedicated "Bluetooth Debugger" mobile app on a mobile phone or computer. The mobile application can visualize the changes in electric current and realize the wireless transmission of the "SOS" distress signal by bending the finger.

[0108] Performance evaluation results:

[0109] (1) Mechanical properties

[0110] The tensile test was carried out using a wick / Roell Z020 universal testing machine equipped with a 50N load cell at a speed of 10 mm min -1 In the cyclic tensile test, the sensing material is stretched to a certain strain and then recovered ten times.

[0111] (2) Conductivity

[0112] The ionic conductivity of the sensing material was measured by dual-probe AC ​​impedance spectroscopy using an electrochemical workstation. The sample was sandwiched between two copper electrodes and the 5 The measurement was performed at a frequency of Hz and an oscillation amplitude of 5 mV. The ionic conductivity σ (S / m) of the organohydrogel at different temperatures was calculated according to the following formula (1):

[0113]

[0114] Where L(m) is the distance between the two electrodes, S(m 2 ) is the cross-sectional area of ​​the hydrogel, and R (Ω) is the resistance obtained from the Nyquist plot. The ionic conductivity of the sensing material at different temperatures was measured using a Peltier temperature control device.

[0115] (3) Antifreeze performance

[0116] The antifreeze performance of the sensing material was tested by DSC test. The sample (6-10 mg) was placed in an aluminum pan and then transferred to the DSC system. The sample was heated at -10 °C min -1 The temperature was cooled from 30°C to -120°C at a rate of 100 °C / min, kept at -120°C for 5 min, and then -1 The temperature was returned to 30°C at a speed of 100°C. The heat flow during the cooling and heating process was monitored in real time.

[0117] (4) Stretch sensing performance

[0118] The electrical signals of the sensing material were recorded by an electrochemical workstation. In room temperature testing, the prepared organic hydrogel was connected to flexible copper electrodes at both ends to form a sensing material, which was then attached to the human body. Various strain signals were detected in real time at a constant voltage of 1V. For low-temperature testing, the sensing material was placed on a cooling platform at -78°C for 6 hours. The relative change in resistance was calculated using the following formula (2):

[0119]

[0120] Where R0 and R are the original resistance and real-time resistance when the strain is 0%, respectively.

[0121] The strain sensitivity is calculated according to the following formula (3):

[0122]

[0123] (5) Wireless human-computer interaction at ultra-low temperatures

[0124] The organohydrogel was fabricated into a 30×8×1mm rectangular sheet, which was then connected to flexible silver electrodes at both ends and encapsulated with VHB tape to create an extremely low-temperature-resistant sensing material. A wireless Bluetooth transmission module and a Morse code-based communication mechanism were developed to connect to the sensing material (SOS stands for "···---···," with "·" and "-" representing a small (30°) and large (90°) finger bend, respectively). The sensing material was attached to the finger joints of a robotic hand, with silver wires used as the electrode layer. The sheets were encapsulated on both sides with copper foil tape and connected in series to the Bluetooth transmission module. Simulating polar temperatures, a 1V voltage was applied from a portable regulated power supply at -78°C. The finger bending signal was further modulated by the Bluetooth transmission module's microcontroller, converted into a corresponding current signal via an analog-to-digital converter, and then wirelessly transmitted to a dedicated "Bluetooth Debugger" mobile app on a phone or computer. The mobile app visualizes the current changes, enabling wireless transmission of the "SOS" distress signal based on the finger bending arc.

[0125] Table 1 Test results of extreme low temperature resistant sensing materials for polar exploration

[0126]

[0127] Among them, Example 5 exhibits the best comprehensive performance, extreme low temperature resistance (-103.6°C), higher elongation at break (1750%) and highest conductivity (1.59S / m), and has higher sensitivity (GF=6.55), indicating that it has a large resistance / current signal response even under small deformation. Combined with the high elongation at break of the sensing material, it is proved that the sensing material has a wide working range and response capability in practical applications.

[0128] While the present invention has been described in detail and specific embodiments thereof have been illustrated by way of example in the Examples, the present invention is susceptible to various modifications and alternative forms. It should be understood that the present invention is not limited to the specific forms disclosed. The present invention encompasses all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A method for preparing an extremely low-temperature-resistant sensing material that can be used for polar exploration, characterized in that: The following steps are involved: (1) Preparation of extremely low-temperature resistant organohydrogel precursor solution: Solution A: 100-200 parts by weight of organic solvent α and 100-200 parts by weight of water are prepared into a binary solvent; Solution B: Dissolve 50-70 parts by weight of a hydrophilic monomer, 0.0001-0.001 parts by weight of a cross-linking agent, and 0.1-0.2 parts by weight of an initiator in 200-400 parts by weight of binary solution A and stir at room temperature for 5 minutes; then add 0.1-0.2 parts by weight of an emulsifier and 0.1-0.2 parts by weight of a hydrophobic monomer, and sonicate using a cell disrupter for 2-10 minutes; finally, add 0.1-0.2 parts by weight of cellulose and 0.1-0.2 parts by weight of an inorganic salt, and stir at room temperature for 1 hour to obtain an antifreeze organohydrogel precursor solution; (2) Preparation of biomimetic adhesive: Solution C: dissolving 1-2 parts by weight of a polyphenol compound in 20-30 parts by weight of solvent water; Solution D: Dissolve 1-2 parts by weight of branched polyethyleneimine in 20-30 parts by weight of solvent water; Solution D is added to solution C, mixed, and then the pH is adjusted to 4-5 with an acidic solution to obtain a biomimetic adhesive; (3) Preparation of extremely low-temperature resistant organic hydrogels: 10-100 parts by weight of the antifreeze organohydrogel precursor solution prepared in step (1) and 10-100 parts by weight of the biomimetic adhesive prepared in step (2) are mixed evenly, poured into a polytetrafluoroethylene mold, and cured under ultraviolet light for 1 hour to obtain an extremely low-temperature-resistant organohydrogel; (4) Preparation of extremely low temperature resistant sensing materials: The extremely low-temperature-resistant organic hydrogel prepared in step (3) was used to prepare a 30×8×1 mm rectangular sheet, which was then connected to flexible silver electrodes at both ends and encapsulated with VHB tape to obtain an extremely low-temperature-resistant sensing material; The organic solvent α refers to one or more of ethylene glycol, glycerol, and dimethyl sulfoxide; The hydrophilic monomer refers to one or more of acrylamide, acrylic acid, and polyvinyl alcohol; The hydrophobic monomer is one or more of octadecyl methacrylate, lauryl methacrylate, trifluoroethyl methacrylate, pentafluoropropyl methacrylate, perfluorohexylethyl methacrylate, and perfluorooctylethyl acrylate; The inorganic salt refers to one or more of calcium chloride dihydrate, anhydrous calcium chloride and magnesium chloride.

2. The method for preparing an extremely low-temperature-resistant sensing material that can be used for polar exploration according to claim 1, characterized in that The cross-linking agent refers to one or more of polyethylene glycol diacrylate and N,N-methylenebisacrylamide.

3. The method for preparing an extremely low-temperature-resistant sensing material that can be used for polar exploration according to claim 1, characterized in that The initiator is one of 2,2'-azo(2-methylpropylamidine) dihydrochloride, ammonium persulfate, potassium persulfate, and azobisisobutyronitrile.

4. The method for preparing an extremely low-temperature-resistant sensing material that can be used for polar exploration according to claim 1, characterized in that The emulsifier is one or more of fatty alcohol polyoxyethylene ether, cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, and sodium lauryl sulfate.

5. The method for preparing an extremely low-temperature-resistant sensing material that can be used for polar exploration according to claim 1, characterized in that The polyphenol compounds include one or more of dopamine, tannic acid, catechol, gallic acid and catechin.

6. Application of the extremely low-temperature-resistant sensing material for polar exploration prepared by the method according to claim 1, characterized in that: The following steps are involved: A wireless Bluetooth transmission module that can be connected to the sensing material has been developed. It includes a microcontroller, an analog-to-digital converter, a removable power input interface, an external regulated power input interface, and a signal input interface. The motion or physiological signal from the input end is converted into a related voltammogram through the wireless Bluetooth transmission module and transmitted to the smart device. Based on the wireless Bluetooth transmission module, a communication mechanism based on Morse code was developed. The 26 English letters were encoded using different combinations of the "·" and "-" symbols. The SOS code was defined as "···---···", and a small bend of the finger by 30° and a large bend of the finger by 90° were encoded as "·" and "-", respectively. The sensing material was attached to the finger joints of the robot, and silver wire was selected as the electrode layer. The two sides were encapsulated with copper foil tape and connected in series with the Bluetooth transmission module. A 1V voltage was applied through a mobile regulated power supply at -78°C to simulate polar temperatures. The finger bending signal of the robot was modulated by the microcontroller of the Bluetooth transmission module and converted into a corresponding current signal by an analog-to-digital converter. It was then wirelessly transmitted to a dedicated mobile application "Bluetooth Debugger" on a mobile phone or computer. This mobile application can visualize the current, and the wireless transmission of the "SOS" distress signal can be achieved through the bending arc of the finger.

Images