A preparation process of multi-quantum dot substrate

Abstract

The present invention relates to a preparation process of a multi-quantum dot substrate. The present invention provides a first PDMS substrate; irradiates the first PDMS substrate to improve the hydrophobicity of the surface of the first PDMS substrate to obtain a hydrophilic second PDMS substrate; expands the second PDMS substrate to obtain a hydrophilic and expanded third PDMS substrate; makes a layer of hexagonal close-packed PS microsphere structure layer on the surface of the third PDMS substrate; wet-etches the hexagonal close-packed PS microsphere structure layer to form a micro-cone convex structure of the PS microspheres to form a hexagonal arrangement of PS microcone structure layer; cools the third PDMS substrate to shrink during the cooling process, so that the hexagonal arrangement of PS microcone structure layer forms a hexagonal close-packed PS microcone structure layer with a higher arrangement density; and prepares a molecular polymer layer on the hexagonal close-packed PS microcone structure layer. The present invention can significantly improve the detection limit and sensitivity of flexible sensors.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible sensors, and in particular to a preparation process of a multi-quantum dot substrate. Background Art

[0002] Flexible sensors have attracted widespread attention in the field of health monitoring due to their diverse shapes and ability to fit closely to the human body. Sensors that can accurately monitor motion status are urgently needed for real-time monitoring of patients. Flexible pressure sensors can monitor and identify various human motion signals, including walking, pulse / heart rate, sound, hand movements, and knee joint movements, and convert these physiological information into visual, real-time pulse signals. Mechanical durability, ultra-conformity, and flexibility in sensitivity are key monitoring factors for healthy electronic skin applications. Currently, various strategies have been adopted to improve the sensitivity of flexible pressure sensors, such as device and material structure optimization and sensor unit integration. Despite continuous improvements in these aspects, biocompatibility, health, and safety of flexible pressure sensors are often overlooked, which undoubtedly limits the application of electronic skin in practical medical monitoring.

[0003] Quantum dots are widely used in fluorescent labeling and bioimaging due to their attractive optoelectronic properties. Quantum dot-based sensors also have broad application prospects in new sensor systems because of their high sensitivity in detecting specific analytes in the chemical and biochemical fields. Although the flexible sensors currently on the market can achieve a certain degree of sensitivity, their detection limit is still not ideal. This deficiency limits the application of sensors in more delicate and demanding detection tasks. Summary of the invention

[0004] To this end, the present invention provides a preparation process of a multi-quantum dot substrate, which can significantly improve the sensitivity and detection limit of the flexible sensor.

[0005] In order to solve the above technical problems, the present invention provides a preparation process of a multi-quantum dot substrate, comprising:

[0006] Providing a first PDMS substrate;

[0007] performing irradiation treatment on the first PDMS substrate to improve the surface hydrophobicity of the first PDMS substrate to obtain a hydrophilic second PDMS substrate;

[0008] Expansion treating the second PDMS substrate to obtain a hydrophilic and expanded third PDMS substrate;

[0009] Making a hexagonal close-packed PS microsphere structure layer on the surface of the third PDMS substrate;

[0010] Wet etching the hexagonally closely packed PS microsphere structure layer to form a micro-cone pointed convex structure of the PS microspheres, thereby forming a hexagonally arranged PS micro-cone structure layer;

[0011] Cooling the third PDMS substrate so that it shrinks during the cooling process, so that the hexagonally arranged PS micro-cone structure layer forms a hexagonally closely packed PS micro-cone structure layer with a higher arrangement density;

[0012] A molecular polymer layer is prepared on the hexagonal close-packed PS micro-cone structure layer.

[0013] In one embodiment of the present invention, a first PDMS substrate is provided, comprising:

[0014] Add PDMS prepolymer and curing agent into a centrifuge tube at a mass ratio of 10:1 and mix well;

[0015] The mixture was placed in a centrifuge and centrifuged at 8000 rpm for 10 minutes to remove bubbles therein. After the mixture was solidified and formed, the first PDMS substrate was obtained.

[0016] In one embodiment of the present invention, the first PDMS substrate is irradiated, comprising:

[0017] The irradiation treatment is performed by using a 10-40W ozone ultraviolet lamp at a distance of 2-6 mm from the surface of the first PDMS substrate.

[0018] In one embodiment of the present invention, the expansion treatment of the second PDMS substrate comprises:

[0019] The second PDMS substrate is placed in an oven at 80-150° C. and heated and baked for 30-90 minutes to expand it.

[0020] In one embodiment of the present invention, a hexagonal close-packed PS microsphere structure layer is prepared on the surface of the third PDMS substrate, comprising:

[0021] The third PDMS substrate is placed horizontally, and a PS microsphere latex solution is vertically dropped on the surface of the third PDMS substrate, and the liquid medium in the PS microsphere latex solution is completely evaporated to form unevenly distributed PS microspheres on the surface of the third PDMS substrate;

[0022] The third PDMS substrate with PS microspheres is subjected to water bath treatment to form a hexagonal close-packed PS microsphere structure layer on the surface of the third PDMS substrate.

[0023] In one embodiment of the present invention, the third PDMS substrate with PS microspheres is subjected to a water bath treatment, comprising:

[0024] The third PDMS substrate with PS microspheres is placed in warm water for self-assembly. When the warm water reaches the surface of the third PDMS substrate, the PS microspheres distributed on the surface can shrink and form a hexagonal close-packed structure.

[0025] In one embodiment of the present invention, the temperature of the warm water is 20-40° C., and the water bath time is 10-30 min.

[0026] In one embodiment of the present invention, cooling the third PDMS substrate comprises:

[0027] The third PDMS substrate is placed in a refrigerator at a temperature range of 0-10° C. for 1-3 hours for cooling.

[0028] In one embodiment of the present invention, a molecular polymer layer is prepared on the hexagonal close-packed PS micro-cone structure layer, comprising:

[0029] Depositing a gold coupling agent layer on the surface of the hexagonal close-packed PS micro-cone structure layer by a magnetron sputtering process;

[0030] Use 5-20 μM 4-ATP solution to react with the gold coupling agent layer under acidic conditions;

[0031] After the reaction, 4-ATP molecules are adsorbed on the Au surface through Au-S bonds to form a molecular polymer layer.

[0032] In one embodiment of the present invention, the thickness of the molecular polymer layer is 50-100 nm.

[0033] The above technical solution of the present invention has the following advantages compared with the prior art:

[0034] The preparation process of a multi-quantum dot substrate described in the present invention is to expand the flexible substrate by heat through a high-temperature thermal expansion process, and self-assemble PS balls on the expanded flexible substrate to form a single-layer hexagonal close-packed PS microsphere structure. Subsequently, a thorny flexible substrate with a micro-conical pointed convex structure is obtained by wet etching. After the substrate is cooled to room temperature, the thorny structure on the substrate shrinks to form a higher density hexagonal close-packed micro-cone structure, thereby obtaining a high-density quantum dot flexible substrate. Finally, a gold coupling agent is deposited on the micro-cone structure by a magnetron sputtering process, and a 4-ATP solution is used to react with the Au coupling agent under acidic conditions to form a molecular polymer layer. After this high-density quantum dot flexible substrate is combined with the detection substance, the excitation energy is enhanced, which can significantly improve the detection limit and sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0036] Figure 1 It is a schematic structural diagram of the third PDMS substrate of the present invention.

[0037] Figure 2 It is a schematic diagram of the cross-sectional structure of the hexagonal close-packed PS microsphere structure layer on the third PDMS substrate of the present invention.

[0038] Figure 3 It is a schematic diagram of the top view of the hexagonal close-packed PS microsphere structure layer on the third PDMS substrate of the present invention.

[0039] Figure 4 It is a schematic diagram of the cross-sectional structure of the hexagonally arranged PS micro-cone structure layer on the third PDMS substrate of the present invention.

[0040] Figure 5 It is a schematic diagram of the top view of the structure of the hexagonally arranged PS micro-cone structure layer on the third PDMS substrate of the present invention.

[0041] Figure 6 It is a schematic diagram of the cross-sectional structure of the hexagonal close-packed PS micro-cone structure layer on the third PDMS substrate of the present invention.

[0042] Figure 7 It is a schematic diagram of the top view of the hexagonal close-packed PS microsphere structure layer on the third PDMS substrate of the present invention.

[0043] Figure 8 It is a schematic diagram of depositing a gold (Au) coupling agent layer on the surface of a hexagonal close-packed PS micro-cone structure layer according to the present invention.

[0044] Fig. 9 Schematic cross-sectional view of a substrate formed according to the present invention.

[0045] Fig.10 It is a schematic diagram of the top view of the substrate formed by the present invention.

[0046] Fig.11 It is a schematic diagram of excitation energy comparison of the substrate formed by the present invention.

[0047] Description of the Figures in the Specification:

[0048] 1. The third PDMS substrate;

[0049] 2. Hexagonal close-packed PS microsphere structure layer;

[0050] 3. Hexagonally arranged PS micro-cone structure layer;

[0051] 4. Hexagonal close-packed PS micro-cone structure layer;

[0052] 5. Gold coupling agent layer;

[0053] 6. Molecular polymer layer. DETAILED DESCRIPTION

[0054] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0055] In the present invention, if directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present invention, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention.

[0056] In the present invention, "several" means one or more, "multiple" means more than two, "greater than", "less than", "exceed" and the like are understood to exclude the number itself; "above", "below", "within" and the like are understood to include the number itself. In the description of the present invention, if there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0057] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected or electrically connected or able to communicate with each other; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0058] Reference Figure 1 As shown, a preparation process of a multi-quantum dot substrate of the present invention comprises the following steps:

[0059] S1. Provide a first PDMS substrate (PDMS, dimethylsiloxane). It includes:

[0060] Add PDMS prepolymer and curing agent into a centrifuge tube at a mass ratio of 10:1 and mix well;

[0061] The mixture was placed in a centrifuge and centrifuged at 8000 rpm for 10 minutes to remove bubbles therein. After the mixture was solidified and formed, the first PDMS substrate was obtained.

[0062] S2, irradiating the first PDMS substrate with an ozone ultraviolet lamp to improve the hydrophobicity of the surface of the PDMS substrate to obtain a hydrophilic second PDMS substrate.

[0063] A 10-40W ozone ultraviolet lamp is used to irradiate the first PDMS substrate for a period of time at a distance of 2-6 mm from the surface of the first PDMS substrate. Through the irradiation treatment, the hydrophobicity of the surface of the first PDMS substrate is improved to make it hydrophilic.

[0064] S3, swelling the second PDMS substrate to obtain a hydrophilic and swollen third PDMS substrate 1. Figure 1 As shown. Includes:

[0065] The second PDMS substrate is placed in an oven at 80-150° C. and heated and baked for 30-90 minutes to expand it.

[0066] S4, making a layer of hexagonal close-packed PS microsphere structure layer 2 on the surface of the third PDMS substrate 1. Figure 3 As shown. Includes:

[0067] The third PDMS substrate 1 is placed horizontally, and a PS microsphere latex solution (PS, polystyrene) is vertically dropped on the surface of the third PDMS substrate 1. The PS microsphere latex solution is a suspension in which PS microspheres are dispersed in a liquid medium (usually water or other solvents). When the liquid medium in the PS microsphere latex solution is completely volatilized, unevenly distributed PS microspheres are formed on the surface of the third PDMS substrate 1.

[0068] The third PDMS substrate 1 with PS microspheres is subjected to a water bath treatment to form a hexagonal close-packed PS microsphere structure layer 2 on the surface of the third PDMS substrate 1. Specifically:

[0069] The third PDMS substrate 1 with PS microspheres is placed in warm water at a temperature of 20-40°C for self-assembly. When the warm water reaches the surface of the third PDMS substrate 1, the PS microspheres distributed on the surface can slowly shrink and form a hexagonal close-packed structure, and the excess PS microspheres will sink from the surface of the warm water. After a water bath of 10-30 minutes, a hexagonal close-packed PS microsphere structure layer 2 is formed on the surface of the third PDMS substrate 1.

[0070] It can be understood that self-assembly uses the surface tension of warm water to self-assemble PS microspheres of uniform size and mass together to form a dense and thin layer of PS sphere film. The excess PS microspheres refer to the PS microspheres with a relatively large weight. Their mass does not meet the assembly requirements and will sink from the surface of the water.

[0071] S5, wet-etching the hexagonally closely packed PS microsphere structure layer 2, so that the PS microspheres form a micro-cone convex structure, forming a hexagonally arranged PS micro-cone structure layer 3, with a thickness of 500-1500 μm. Figure 4 , Figure 5 shown.

[0072] Since all surfaces are corroded at the same time during the wet etching process, the ion exchange rate on the upper surface of the PS microsphere is faster, so the corrosion rate of the upper surface of the PS microsphere is faster, and the corrosion rate of the bottom of the PS microsphere is slower, thus forming a micro-conical pointed convex structure. In this process, the gaps between the PS microspheres and the PS microspheres themselves are etched and the volume becomes smaller.

[0073] In order to avoid excessive corrosion, the corrosion time should be strictly controlled, and finally a lower arrangement density (5-10 pieces / mm2) is formed on the third PDMS substrate 1. 2 ) of hexagonally arranged PS micro-cone structure layer 3.

[0074] In addition, due to its pointed shape, the PS microcone structure can significantly increase the density of quantum dots. This structure is conducive to enhancing the surface effect, making the sensor more sensitive to external pressure and deformation. The microcone structure can produce significant electrical signal changes under slight pressure changes, thereby improving the detection sensitivity of the sensor.

[0075] The hexagonal close-packed structure is an efficient way to utilize space. It can accommodate more PS micro-cone structures on a limited surface area and enable the PS micro-cone structures to be evenly distributed on the sensor surface, which helps to evenly transmit and disperse force and improve the overall performance and stability of the sensor.

[0076] S6, placing the third PDMS substrate 1 in a refrigerator with a temperature range of 0-10°C for 1-3 hours, cooling the third PDMS substrate 1 to room temperature (20-30°C); the third PDMS substrate 1 shrinks during the cooling process, and the hexagonally arranged PS micro-cone structure layer 3 on the shrunk third PDMS substrate 1 is further closely arranged to form a higher arrangement density (20-40 / mm 2 ) of hexagonal close-packed PS micro-cone structure layer 4. Figure 6 , Figure 7 shown.

[0077] Through the above treatment, the density of quantum dots can be increased from 5 to 10 per mm. 2 Become 20~40 / mm 2 .

[0078] S7, preparing a molecular polymer layer 6 on the hexagonal close-packed PS micro-cone structure layer 4, with a thickness of 50-100 nm. It includes:

[0079] A gold (Au) coupling agent layer 5 is deposited on the surface of the hexagonal close-packed PS micro-cone structure layer 4 by a magnetron sputtering process. Figure 8 shown.

[0080] A 4-ATP (4-aminothiophenol) solution having a concentration of 5 to 20 μM (micromoles per liter) is used to react with the gold coupling agent layer 5 under acidic conditions;

[0081] After the reaction, the 4-ATP molecules are adsorbed on the Au surface through Au-S bonds (the 4-ATP molecules form Au-S bonds with the gold (Au) surface through their thiol groups (-SH)), forming a molecular polymer layer 6, such as Fig. 9 shown.

[0082] The final base structure reference Fig.10 shown.

[0083] Reference Fig.11 As shown, it can be seen that the excitation energy of the multi-quantum dot substrate obtained by the above preparation process (compared with silicon substrate and low-density quantum dots) has been significantly improved.

[0084] The present invention uses a high-temperature thermal expansion process to expand the flexible substrate when heated, and self-assembles PS balls on the expanded flexible substrate to form a single-layer hexagonal close-packed PS microsphere structure. Subsequently, a thorny flexible substrate with a micro-conical convex structure is obtained by wet etching. After the substrate is cooled to room temperature, the thorny structure on the substrate shrinks to form a higher-density hexagonal close-packed micro-cone structure, thereby obtaining a high-density quantum dot flexible substrate. Finally, a gold (Au) coupling agent is deposited on the micro-cone structure by a magnetron sputtering process, and a 4-ATP solution is used to react with the Au coupling agent under acidic conditions to form a molecular polymer layer 6. After this high-density quantum dot flexible substrate is combined with the detection substance, the detection lower limit and sensitivity can be significantly improved.

[0085] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A preparation process of a multi-quantum dot substrate, characterized in that: include: Providing a first PDMS substrate; performing irradiation treatment on the first PDMS substrate to improve the surface hydrophobicity of the first PDMS substrate to obtain a hydrophilic second PDMS substrate; Expansion treating the second PDMS substrate to obtain a hydrophilic and expanded third PDMS substrate; Making a hexagonal close-packed PS microsphere structure layer on the surface of the third PDMS substrate; Wet etching the hexagonally closely packed PS microsphere structure layer to form a micro-cone pointed convex structure of the PS microspheres, thereby forming a hexagonally arranged PS micro-cone structure layer; Cooling the third PDMS substrate so that it shrinks during the cooling process, so that the hexagonally arranged PS micro-cone structure layer forms a hexagonally closely packed PS micro-cone structure layer with a higher arrangement density; preparing a molecular polymer layer on the hexagonal close-packed PS micro-cone structure layer; Wherein, a layer of hexagonal close-packed PS microsphere structure layer is made on the surface of the third PDMS substrate, comprising: The third PDMS substrate is placed horizontally, and a PS microsphere latex solution is vertically dropped on the surface of the third PDMS substrate, and the liquid medium in the PS microsphere latex solution is completely evaporated to form unevenly distributed PS microspheres on the surface of the third PDMS substrate; The third PDMS substrate with PS microspheres is subjected to a water bath treatment to form a hexagonal close-packed PS microsphere structure layer on the surface of the third PDMS substrate; The third PDMS substrate with PS microspheres is subjected to a water bath treatment, comprising: Placing the third PDMS substrate with PS microspheres in warm water for self-assembly, when the warm water reaches the surface of the third PDMS substrate, the PS microspheres distributed on the surface can shrink and form a hexagonal close-packed structure; Wherein, cooling the third PDMS substrate comprises: The third PDMS substrate is placed in a refrigerator at a temperature range of 0-10° C. for 1-3 h for cooling; Wherein, the expansion treatment of the second PDMS substrate comprises: The second PDMS substrate is placed in an oven at 80-150° C. and heated and baked for 30-90 minutes to expand the substrate; Wherein, a molecular polymer layer is prepared on the hexagonal close-packed PS micro-cone structure layer, comprising: Depositing a gold coupling agent layer on the surface of the hexagonal close-packed PS micro-cone structure layer by a magnetron sputtering process; Use 5-20 μM 4-ATP solution to react with the gold coupling agent layer under acidic conditions; After the reaction, 4-ATP molecules are adsorbed on the Au surface through Au-S bonds to form a molecular polymer layer.

2. A process for preparing a multi-quantum dot substrate according to claim 1, characterized in that: A first PDMS substrate is provided, comprising: Add PDMS prepolymer and curing agent into a centrifuge tube at a mass ratio of 10:1 and mix well; The mixture was placed in a centrifuge and centrifuged at 8000 rpm for 10 minutes to remove bubbles therein. After the mixture was solidified and formed, the first PDMS substrate was obtained.

3. The preparation process of a multi-quantum dot substrate according to claim 1, characterized in that: The first PDMS substrate is subjected to irradiation treatment, comprising: The irradiation treatment is performed by using a 10-40W ozone ultraviolet lamp at a distance of 2-6 mm from the surface of the first PDMS substrate.

4. The preparation process of a multi-quantum dot substrate according to claim 1, characterized in that: The temperature of the warm water is between 20 and 40° C., and the water bath time is between 10 and 30 minutes.

5. The process for preparing a multi-quantum dot substrate according to claim 1, characterized in that: The thickness of the molecular polymer layer is between 50 and 100 nm.

Images