Flexible pressure sensor with warm tactile synergistic response and method of making same

Abstract

The application provides a flexible pressure sensor with temperature-haptic synergistic response and a preparation method thereof, which comprises: an upper electrode for transmitting a capacitance or resistance signal; a conductive nanocomposite layer for forming a conductive path with the upper electrode to transmit the resistance signal; a temperature-sensitive insulating layer arranged between the upper electrode and the conductive nanocomposite layer for blocking the contact between the upper electrode and the conductive nanocomposite layer; and a conformal electrode microstructure array arranged below the conductive nanocomposite layer for forming a capacitance with the upper electrode and forming a conductive path with the upper electrode and the conductive nanocomposite layer. Therefore, the flexible pressure sensor with temperature-haptic synergistic response and the preparation method thereof can convert an electric signal, determine whether the environmental temperature reaches a dangerous temperature according to the type of the electric signal output by the sensor, and realize active adjustment of haptics through temperature stimulation.

Description

Technical Field

[0001] This invention relates to the field of flexible sensor technology, specifically to a flexible pressure sensor with temperature and tactile feedback response and its fabrication method. Background Technology

[0002] As the largest organ in the human body, the skin covers the entire body and possesses unique sensory functions. Information from different sensory neurons is integrated and processed in the central nervous system to perceive the properties of objects or the surrounding environment; this multi-sensory experience is the core of human perception. Touch and temperature perception have different receptors in the skin and possess independent tactile and thermal sensing systems. Touch and temperature perception also differ significantly in reaction time and spatial resolution; however, the human body does not readily perceive these differences, indicating a complementary mechanism between them. A more vivid example is when the skin comes into contact with a very hot object; thermal perception triggers tactile perception, causing the body to react—a self-protective mechanism developed during human evolution.

[0003] In recent years, the rapid development of the information age has led to the widespread application of flexible pressure sensors in fields such as intelligent robots, prosthetics, human health monitoring, and virtual reality. Researchers are integrating multiple types of sensing units that perceive different physical quantities into one unit, hoping to develop electronic skin that mimics the multisensory functions of human skin. However, these multimodal or multifunctional sensors cannot simulate the human body's self-protective mechanisms in response to external high-temperature stimuli.

[0004] Currently, most multi-mode or multi-functional flexible sensors are limited to independent signal acquisition and parallel processing, lacking the cross-modal collaborative response capability of the human body, and making it difficult to achieve active regulation of tactile sensation through temperature stimulation. Summary of the Invention

[0005] This invention is made to solve the above-mentioned problems, and aims to provide a flexible pressure sensor with temperature-touch synergy response and its preparation method.

[0006] This invention provides a flexible pressure sensor with temperature-tactile synergistic response, characterized by: an upper electrode for transmitting capacitive or resistive signals; a conductive nanocomposite layer for forming a conductive path with the upper electrode to transmit resistive signals; a temperature-sensitive insulating layer disposed between the upper electrode and the conductive nanocomposite layer to prevent contact between the upper electrode and the conductive nanocomposite layer; and a conformal electrode microstructure array disposed below the conductive nanocomposite layer to form a capacitor with the upper electrode and a conductive path with the upper electrode and the conductive nanocomposite layer.

[0007] The flexible pressure sensor with temperature-touch synergy response provided by the present invention may also have the following feature: the resistance of the conductive nanocomposite layer changes when subjected to external pressure.

[0008] The flexible pressure sensor with temperature-tactile synergy provided by the present invention may also have the following feature: the temperature-sensitive insulating layer melts when the ambient temperature reaches the phase transition temperature, and the phase transition temperature is adjustable as needed.

[0009] This invention provides a method for fabricating a flexible pressure sensor with temperature-touch synergy response, characterized by the following steps: Step S1, attaching a conductive nanocomposite material layer to a conformal electrode microstructure array; Step S2, heating and melting n-eicosane, coating it onto the upper surface of the conductive nanocomposite material layer, and waiting for it to cool and solidify; Step S3, attaching copper tape to the upper surface of the n-eicosane-coated conductive nanocomposite material layer to serve as the upper electrode, and encapsulating it into a sensor.

[0010] The method for preparing a flexible pressure sensor with synergistic temperature and touch response provided by the present invention may also have the following features: the method for preparing the conductive nanocomposite material layer includes: step T1, adding polydimethylsiloxane, multi-walled carbon nanotubes and n-hexane to a beaker; step T2, heating the beaker while magnetically stirring, mixing evenly and then turning off the heating, adding polydimethylsiloxane curing agent to the beaker, and continuing to stir evenly to form a first mixture; step T3, vacuuming the first mixture and pouring it onto a glass plate to form a thin film by a scraping method, then placing it in an oven for heating to obtain a cured conductive nanocomposite material film as the conductive nanocomposite material layer.

[0011] The method for preparing a flexible pressure sensor with synergistic temperature and tactile response provided by the present invention may also have the following feature: wherein the mass ratio of polydimethylsiloxane body to polydimethylsiloxane curing agent is 10:1.

[0012] The method for preparing a flexible pressure sensor with synergistic temperature and tactile response provided by the present invention may also have the following feature: wherein the mass fraction of multi-walled carbon nanotubes is 3% of polydimethylsiloxane and polydimethylsiloxane curing agent.

[0013] The method for preparing a flexible pressure sensor with synergistic temperature and tactile response provided by the present invention may also have the following feature: the thickness of the conductive nanocomposite film is achieved by adjusting the height of the scraper.

[0014] The method for preparing a flexible pressure sensor with synergistic temperature and touch response provided by this invention may also have the following features: the method for preparing a conformal electrode microstructure array includes: step U1, adding polydimethylsiloxane proton and polydimethylsiloxane curing agent to a beaker to obtain a second mixture, and stirring with a glass rod; step U2, subjecting the second mixture to vacuum treatment, pouring it into a mold, and then placing it in an oven for heating to obtain a polydimethylsiloxane microstructure array; step U3, immersing the polydimethylsiloxane microstructure array in anhydrous ethanol, and then performing plasma cleaning to obtain a treated polydimethylsiloxane microstructure array; step U4, subjecting the treated polydimethylsiloxane microstructure array to magnetron sputtering to obtain a conformal electrode microstructure array.

[0015] The method for preparing a flexible pressure sensor with temperature-touch synergy provided by the present invention may also have the following feature: wherein the mold contains an array of hemispherical concave holes with a radius of 1 mm, and the mold material is copper.

[0016] The role and effect of the invention:

[0017] The flexible pressure sensor with thermo-tactile synergistic response and its fabrication method according to the present invention comprises: an upper electrode for transmitting capacitive or resistive signals; a conductive nanocomposite layer for forming a conductive path with the upper electrode and transmitting resistive signals; a temperature-sensitive insulating layer disposed between the upper electrode and the conductive nanocomposite layer for preventing contact between the upper electrode and the conductive nanocomposite layer; and a conformal electrode microstructure array disposed below the conductive nanocomposite layer for forming capacitance with the upper electrode and forming a conductive path with the upper electrode and the conductive nanocomposite layer. Therefore, the flexible pressure sensor with thermo-tactile synergistic response and its fabrication method of the present invention can convert electrical signals, determine whether the ambient temperature has reached a dangerous temperature based on the type of electrical signal output by the sensor, and achieve active regulation of tactile sensation through temperature stimulation. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a flexible pressure sensor with temperature-touch synergistic response in an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram illustrating the working principle of a flexible pressure sensor with temperature-touch synergy response in an embodiment of the present invention.

[0020] Figure 3 This is a schematic flowchart illustrating the fabrication method of a flexible pressure sensor with temperature-touch synergy in an embodiment of the present invention.

[0021] Figure 4 This is a schematic flowchart of the method for preparing the conductive nanocomposite material layer in an embodiment of the present invention.

[0022] Figure 5 This is a schematic flowchart of the fabrication method of the conformal electrode microstructure array in an embodiment of the present invention.

[0023] Figure 6 This is a SEM schematic diagram of the conductive nanocomposite material in an embodiment of the present invention.

[0024] Figure 7 This is a temperature response pattern diagram of a robot grasping a cold water cup, which is equipped with a flexible pressure sensor that provides temperature and tactile feedback in an embodiment of the present invention.

[0025] Figure 8 This is a temperature response pattern diagram of a robot grasping a hot water cup, which is equipped with a flexible pressure sensor that provides temperature and tactile feedback in an embodiment of the present invention.

[0026] Figure 9 This is a Morse code sensing and signal response diagram of a flexible pressure sensor with temperature-touch synergy in an embodiment of the present invention. Detailed Implementation

[0027] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0028] To make the technical means, creative features, objectives and effects of the present invention easy to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate the flexible pressure sensor with temperature-touch synergy response of the present invention and its preparation method.

[0029] Example:

[0030] Figure 1 This is a schematic diagram of the structure of a flexible pressure sensor with temperature-touch synergistic response in an embodiment of the present invention.

[0031] like Figure 1 As shown, this embodiment provides a flexible pressure sensor 100 with temperature and tactile response, including: an upper electrode 10, a conductive nanocomposite material layer 20, a temperature-sensitive insulating layer 30, and a conformal electrode microstructure array 40.

[0032] The upper electrode 10 is used to transmit capacitance or resistance signals.

[0033] A conductive nanocomposite layer 20 is disposed below the upper electrode 10 to form a conductive path with the upper electrode 10 and transmit resistance signals. The resistance of the conductive nanocomposite layer 20 changes when subjected to external pressure.

[0034] A temperature-sensitive insulating layer 30 is disposed between the upper electrode 10 and the conductive nanocomposite material layer 20 to prevent the upper electrode 10 from contacting the conductive nanocomposite material layer 20. The temperature-sensitive insulating layer 30 melts when the ambient temperature reaches the phase transition temperature, which can be adjusted as needed.

[0035] The conformal electrode microstructure array 40 is disposed below the conductive nanocomposite material layer 20 to form a capacitor with the upper electrode 10 and a conductive path with the upper electrode 10 and the conductive nanocomposite material layer 20. The conformal electrode microstructure array 40 also includes a microstructure substrate 401 disposed below the conformal electrode microstructure array 40 to provide flexible support.

[0036] Figure 2 This is a schematic diagram illustrating the working principle of a flexible pressure sensor with temperature-touch synergy response in an embodiment of the present invention.

[0037] like Figure 2 As shown, the working principle of the flexible pressure sensor 100 with temperature and tactile feedback in this embodiment is as follows:

[0038] At room temperature, the flexible pressure sensor 100 with temperature-tactile synergy is a capacitive pressure sensor due to the presence of the temperature-sensitive insulating layer 30. When subjected to external pressure, the capacitance between the conformal electrode microstructure array 40 and the upper electrode 10 changes, and external devices can sense pressure by detecting the change in the capacitance signal output by the sensor. When the ambient temperature reaches the phase transition temperature of the temperature-sensitive insulating layer 30, the temperature-sensitive insulating layer 30 melts, causing the upper electrode 10 to come into contact with the conductive nanocomposite material layer 20, forming a conductive path between the conformal electrode microstructure array 40 and the upper electrode 10, and the sensor transforms into a resistive pressure sensor. When subjected to external pressure, the resistance of the conductive nanocomposite material layer 20 changes, and external devices can sense pressure by detecting the change in the resistance signal output by the sensor. The type of electrical signal output by the sensor can be used to determine whether the ambient temperature has reached a dangerous temperature.

[0039] Figure 3 This is a schematic flowchart illustrating the fabrication method of a flexible pressure sensor with temperature-touch synergy in an embodiment of the present invention.

[0040] like Figure 3 As shown, this embodiment also provides a method for fabricating a flexible pressure sensor with coordinated temperature and tactile response, including:

[0041] Step S1: The conductive nanocomposite material layer 20 is attached to the conformal electrode microstructure array 40. In this embodiment, the conductive nanocomposite material layer 20 is cut to 15mm × 15mm.

[0042] Figure 4 This is a schematic flowchart of the method for preparing the conductive nanocomposite material layer in an embodiment of the present invention.

[0043] like Figure 4 As shown, the method for preparing the conductive nanocomposite layer 20 includes:

[0044] In step T1, polydimethylsiloxane (PDMS) matrix, multi-walled carbon nanotubes (MWCNTs), and n-hexane are added to a beaker. The mass fraction of MWCNTs is 3% of the sum of the mass of PDMS matrix and PDMS curing agent. n-Hexane is used as a solvent and does not participate in the reaction; in this example, 4g of n-hexane is added.

[0045] In step T2, while heating the beaker, magnetic stirring is performed until the mixture is homogeneous. Heating is then turned off, and polydimethylsiloxane curing agent is added to the beaker. Stirring continues for 10 minutes until a homogeneous first mixture is formed. The mass ratio of polydimethylsiloxane alkyl body to polydimethylsiloxane curing agent is 10:1. The mass fraction of multi-walled carbon nanotubes is 3% of the total mass of polydimethylsiloxane alkyl body and polydimethylsiloxane curing agent.

[0046] The magnetic stirring was carried out at 80℃ and 1000r / min for 1 hour.

[0047] Step T3 involves vacuuming the first mixture, pouring it onto a glass plate, and forming a thin film using a blade coating method. The film is then placed in an oven and heated to obtain a cured conductive nanocomposite film, which serves as the conductive nanocomposite layer 20. The thickness of the conductive nanocomposite film is adjusted by changing the height of the blade. The vacuuming process takes 15 minutes.

[0048] In this embodiment, the glass plate is placed in an oven and heated to 80°C for 1 hour to complete the curing of the conductive nanocomposite layer 20.

[0049] Figure 5 This is a schematic flowchart of the fabrication method of the conformal electrode microstructure array in an embodiment of the present invention.

[0050] like Figure 5 As shown, the fabrication method of the conformal electrode microstructure array 40 includes:

[0051] Step U1: Add polydimethylsiloxane alkyl body and polydimethylsiloxane curing agent to a beaker to obtain a second mixture, and stir with a glass rod for 5 minutes. The mass ratio of polydimethylsiloxane alkyl body to polydimethylsiloxane curing agent is 10:1.

[0052] Step U2 involves vacuuming the second mixture, pouring it into a mold, and then heating it in an oven to obtain a polydimethylsiloxane microstructure array. The mold contains an array of hemispherical concave holes with a radius of 1 mm, and the mold material is copper. The vacuuming process lasts for 15 minutes. The mixture is then heated in an oven to 80°C for 1 hour to obtain the polydimethylsiloxane microstructure array.

[0053] Step U3: Immerse the polydimethylsiloxane microstructure array in anhydrous ethanol and then perform plasma cleaning to obtain the treated polydimethylsiloxane microstructure array.

[0054] The immersion time in anhydrous ethanol was 2 hours, and the plasma cleaning time was 120 seconds.

[0055] Step U4 involves magnetron sputtering the treated polydimethylsiloxane microstructure array to obtain a conformal electrode microstructure array. The magnetron sputtering current is set to 30 mA, the time to 240 s, and the target material is Pt.

[0056] Step S2: After heating and melting n-eicosane, it is coated onto the upper surface of the conductive nanocomposite layer 20 and left to cool and solidify.

[0057] Step S3: A copper tape is attached to the upper surface of the conductive nanocomposite material layer 20 coated with n-eicosane to serve as the upper electrode 10, and then encapsulated as a sensor. In this embodiment, the copper tape is cut to 15mm × 15mm.

[0058] Figure 6 This is a SEM schematic diagram of the conductive nanocomposite material in an embodiment of the present invention.

[0059] like Figure 6 As shown, the multi-walled carbon nanotube (MWCNTs) / polydimethylsiloxane (PDMS) conductive nanocomposite layer was characterized using scanning electron microscopy (SEM). Figures (a) and (b) show that the MWCNT filler is densely and uniformly distributed within the PDMS matrix, which forms the basis for the conductive network, confirming the effectiveness of the invention. Figures (c) and (d) further demonstrate that the MWCNTs interweave and coil to form a conductive network.

[0060] Figure 7 This is a temperature response pattern diagram of a robot grasping a cold water cup, which is equipped with a flexible pressure sensor that provides temperature and tactile feedback in an embodiment of the present invention.

[0061] like Figure 7 The diagram shows a flexible pressure sensor with thermo-tactile co-responsive design installed at the tip of a robot's finger. The robot's hand grasps a cup of cold water. The pattern of the output electrical signal is used to determine whether it has sensed a dangerous temperature. When grasping the cup of cold water, a capacitance signal is obtained, indicating that the temperature-sensitive insulation layer is in good condition, and the flexible pressure sensor with thermo-tactile co-responsive design is capacitive. When grasping the cup, the external force causes the distance between the two electrodes to decrease, thereby increasing the capacitance, and the rate of change of capacitance also increases accordingly. Three consecutive grasping and releasing actions show that the electrical signal is very stable and responds quickly to the action.

[0062] Figure 8 This is a temperature response pattern diagram of a robot grasping a hot water cup, which is equipped with a flexible pressure sensor that provides temperature and tactile feedback in an embodiment of the present invention.

[0063] like Figure 8 As shown, when a cup full of hot water is grasped, the output electrical signal is converted to a resistive mode. This indicates that the temperature-sensitive insulating layer has melted, and a conductive path has been formed in the flexible pressure sensor, thus converting the sensor to a resistive mode. When the cup is grasped, the conductive nanocomposite layer is subjected to a compressive load, causing its resistance to decrease, resulting in a negative rate of change of resistance. Furthermore, the resistance value in the grasped state is three orders of magnitude smaller than that in the released state. This significant numerical difference leads to a resistance change rate approaching -1 when the cup is grasped.

[0064] In addition, the phase transition temperature of the temperature-sensitive insulation layer can be adjusted to meet the needs of different application scenarios.

[0065] Figure 9 This is a Morse code sensing and signal response diagram of a flexible pressure sensor with temperature-touch synergy in an embodiment of the present invention.

[0066] like Figure 9 As shown, a series of forces with different holding times were applied to a flexible pressure sensor with thermo-tactile co-response to simulate signals in Morse code. The electrical signal of the flexible pressure sensor with thermo-tactile co-response exhibits good distinguishability of different loading responses, without signal ambiguity or indistinguishability. This further demonstrates that the flexible pressure sensor with thermo-tactile co-response possesses good stability, repeatability, and a good force-electrical response, showcasing its application potential in Morse code signal transmission.

[0067] The role and effects of the embodiments:

[0068] According to the flexible pressure sensor with temperature-tactile synergistic response and its preparation method involved in this embodiment, since it includes: an upper electrode for transmitting capacitance or resistance signals; a conductive nanocomposite layer for forming a conductive path with the upper electrode and transmitting resistance signals; a temperature-sensitive insulating layer disposed between the upper electrode and the conductive nanocomposite layer for preventing contact between the upper electrode and the conductive nanocomposite layer; and a conformal electrode microstructure array disposed below the conductive nanocomposite layer for forming capacitance with the upper electrode and forming a conductive path with the upper electrode and the conductive nanocomposite layer, the flexible pressure sensor with temperature-tactile synergistic response and its preparation method of the present invention can convert electrical signals, determine whether the ambient temperature has reached a dangerous temperature based on the type of electrical signal output by the sensor, and achieve active regulation of tactile sensation through temperature stimulation.

[0069] In this embodiment, the phase transition temperature of the temperature-sensitive insulating layer can be adjusted to make the flexible pressure sensor with temperature-touch synergy adaptable to different application scenarios for sensing dangerous temperatures.

[0070] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A flexible pressure sensor with temperature-tactile synergy response, characterized in that, include: The upper electrode is used to transmit capacitance or resistance signals. A conductive nanocomposite layer is used to form a conductive path with the upper electrode to transmit resistance signals; A temperature-sensitive insulating layer is disposed between the upper electrode and the conductive nanocomposite material layer to prevent the upper electrode from contacting the conductive nanocomposite material layer; A conformal electrode microstructure array is disposed below the conductive nanocomposite material layer to form a capacitor with the upper electrode and to form a conductive path with the upper electrode and the conductive nanocomposite material layer; The temperature-sensitive insulating layer melts when the ambient temperature reaches the phase transition temperature. The phase transition temperature is adjusted as needed. When the ambient temperature reaches the phase transition temperature of the temperature-sensitive insulating layer, the melting of the temperature-sensitive insulating layer causes the upper electrode to come into contact with the conductive nanocomposite material layer, forming a conductive path between the conformal electrode microstructure array and the upper electrode, and the sensor is converted into a resistive pressure sensor.

2. The flexible pressure sensor with temperature-tactile synergistic response according to claim 1, characterized in that: in, The electrical resistance of the conductive nanocomposite layer changes when subjected to external pressure.

3. A method for fabricating a flexible pressure sensor with thermo-tactile synergistic response, characterized in that, include: Step S1: Adhere the conductive nanocomposite material layer to the conformal electrode microstructure array; Step S2: After heating and melting n-eicosane, it is coated onto the upper surface of the conductive nanocomposite material layer and left to cool and solidify. Step S3: Attach copper tape to the upper surface of the conductive nanocomposite material layer coated with n-eicosane to serve as the top electrode, and encapsulate it as a sensor.

4. The method for fabricating a flexible pressure sensor with thermo-tactile synergistic response according to claim 3, Its features are: The method for preparing the conductive nanocomposite material layer includes: Step T1: Add polydimethylsiloxane, multi-walled carbon nanotubes and n-hexane to a beaker; Step T2: While heating the beaker, magnetic stirring is performed. After mixing evenly, the heating is turned off, polydimethylsiloxane curing agent is added to the beaker, and stirring is continued to form a first mixture. Step T3: After vacuum treatment, the first mixture is poured onto a glass plate and coated to form a thin film. Then, it is placed in an oven for heating to obtain a cured conductive nanocomposite film as the conductive nanocomposite layer.

5. The method for fabricating a flexible pressure sensor with thermo-tactile synergistic response according to claim 4, characterized in that: in, The mass ratio of the polydimethylsiloxane body to the polydimethylsiloxane curing agent is 10:

1.

6. The method for fabricating a flexible pressure sensor with thermo-tactile synergistic response according to claim 4, characterized in that: in, The mass fraction of the multi-walled carbon nanotubes is 3% of the polydimethylsiloxane and polydimethylsiloxane curing agent.

7. The method for fabricating a flexible pressure sensor with thermo-tactile synergistic response according to claim 4, characterized in that: in, The thickness of the conductive nanocomposite film is achieved by adjusting the height of the scraper.

8. The method for fabricating a flexible pressure sensor with thermo-tactile synergistic response according to claim 3, Its features are: The method for fabricating the conformal electrode microstructure array includes: Step U1: Add polydimethylsiloxane and polydimethylsiloxane curing agent to a beaker to obtain a second mixture, and stir with a glass rod; Step U2: Vacuum the second mixture, pour it into a mold, and then heat it in an oven to obtain a polydimethylsiloxane microstructure array. Step U3: Immerse the polydimethylsiloxane microstructure array in anhydrous ethanol and then perform plasma cleaning to obtain the treated polydimethylsiloxane microstructure array. Step U4: The processed polydimethylsiloxane microstructure array is subjected to magnetron sputtering to obtain the conformal electrode microstructure array.

9. The method for fabricating a flexible pressure sensor with thermo-tactile synergistic response according to claim 8, characterized in that: in, The mold contains an array of hemispherical recesses with a radius of 1 mm, and the mold is made of copper.

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