Photoacoustic transducer and preparation method thereof

Abstract

The invention discloses a photoacoustic transducer device and a preparation method thereof, the photoacoustic transducer device comprises an optical plastic substrate and a photoacoustic transduction layer, the photoacoustic transduction layer is arranged on the optical plastic substrate, and the light transmittance of the optical plastic substrate is gt; and 85% of an optical-grade film. The plastic substrate with high light transmittance is adopted, so that the light loss can be reduced, and meanwhile, compared with glass, the plastic substrate is more suitable for being applied in a human body; due to the high light transmittance of the PMMA film, the photoacoustic conversion efficiency is high, and meanwhile the comprehensive performance of the PMMA film is suitable for curved surface modeling. The structural design of the opto-acoustic transduction layer comprises the thickness design of different layers, so that various performance requirements of the composite film are balanced. The concave surface design meets the application of focused ultrasound, such ultrasound has huge energy at the focus and is called high-intensity focused ultrasound, and the improvement of the focused ultrasound can improve the longitudinal resolution of an image.

Description

Technical Field

[0001] The present invention relates to the field of ultrasonic transducers, and in particular to a photoacoustic transducer device and a preparation method thereof. Background Art

[0002] The basic principle of laser ultrasound is photoacoustic conversion. The pulsed laser is irradiated on the photoacoustic conversion composite material and absorbed by the material. The energy of the high-energy pulsed laser beam is converted into heat energy inside the material. The change in the local temperature of the material causes the material to undergo pulsed thermal expansion after being heated. The effect of local thermal expansion causes the formation of elastic stress waves in the form of pulses in the material, namely ultrasound waves, thereby generating high-amplitude focused pressure pulses. Laser ultrasound is a completely non-contact excitation ultrasound signal. No coupling agent is required between the light and the sample. Therefore, laser acoustic technology can be used for detection in harsh environments such as acid, alkali, high temperature, high pressure and radiation. Ultrasound is defined as sound with a frequency ranging from 20kHz to several GHz, and has shown a wide range of applications in medical imaging, materials science, physics, chemistry and nanotechnology. In classical medical ultrasound, ultrasound pulses are transmitted into the body, and the pulses are reflected as image contrast due to the interface between tissues with different acoustic impedances. The echo pulse carries physiological and pathological information in the tissue. In particular, high-frequency ultrasound with a frequency of >20MHz is very useful for high-resolution (<100μm) biomedical applications, such as endoscopic imaging, ophthalmology, intravascular imaging and dermatology. In the above-mentioned high-resolution all-optical ultrasound imaging application, the probe containing the photoacoustic conversion composite material needs to be moved into the human body. The laser is emitted from the inside of the probe through the optical fiber, which needs to penetrate the base layer of the photoacoustic conversion composite material and then reach the heat absorption layer and the heat expansion layer. Considering that the amplitude of the photoacoustic signal generated in the tissue is very low, reducing light loss is related to whether the minimum detection sensitivity requirement can be met.

[0003] In recent years, people have been committed to optimizing the efficiency of laser ultrasonic conversion, especially for applications that require high-frequency ultrasound. The substrate of the current photoacoustic thin film transducer is generally quartz glass material, and the photoacoustic conversion materials mainly include carbon black, graphene, carbon nanotubes and carbon nanofibers. Most of its manufacturing processes first grow photothermal conversion materials on the substrate, and then integrate thermoelastic materials onto the outer surface of the photothermal material to form a sandwich-structured photoacoustic thin film transducer. For example, Won Baac H, Ok JG, Park HJ, et al. Carbon nanotube composite optoacoustic transmitters for strong and high frequency ultrasound generation [J]. Applied Physics Letters, 2010, 97 (23): 617. DOI: 10.1063 / 1.3522833. However, the use of transparent quartz glass as a substrate is not suitable for in vivo applications.

[0004] A Chinese patent with application number 201811119048.9 discloses a flexible photo-induced ultrasonic thin film transducer, which comprises, from bottom to top, a flexible transparent substrate (120), a light absorbing layer (130) and a thermoelastic layer (140). The flexible substrate (120) is a transparent polydimethylsiloxane polymer; the light absorbing layer (130) is a carbon nanotube; and the thermoelastic layer (140) is a polydimethylsiloxane polymer. The method for preparing a flexible photo-induced ultrasonic thin film transducer is as follows: spin coating a polydimethylsiloxane solution on a glass substrate to prepare a flexible transparent substrate; then pressing an inorganic alumina filter membrane with a carbon nanotube filter cake deposited on it onto the transparent polymer film prepared in the second step, peeling off the inorganic alumina filter membrane, and obtaining a carbon nanotube film with a light absorbing layer transferred on the transparent polymer substrate; spin coating a polydimethylsiloxane polymer on the carbon nanotube film layer, and forming a thermoelastic layer after curing. After the thermoelastic layer is cured, the glass substrate is removed. However, this method introduces a glass substrate, the preparation steps are complicated, and it cannot meet the application of high-resolution all-optical ultrasound imaging.

[0005] Therefore, there is an urgent need for a photoacoustic transducer device and a preparation method thereof that can meet the application of high-resolution all-optical ultrasonic imaging. Summary of the invention

[0006] In order to solve the problem in the above background technology that there is no photoacoustic transducer device suitable for high-resolution all-optical ultrasound imaging in the human body, the present invention provides the following technical solutions:

[0007] A photoacoustic transducer device comprises an optical plastic substrate and a photoacoustic transducer layer. The photoacoustic transducer layer is arranged on the optical plastic substrate. The optical plastic substrate is an optical-grade film with a light transmittance greater than 85%.

[0008] Preferably, the optical plastic substrate is an optical grade PMMA film.

[0009] Preferably, the photoacoustic transducer layer is a composite film of a light absorbing material and a polymer matrix, and the polymer matrix is ​​polydimethylsilane;

[0010] Or the photoacoustic transducer layer includes a light absorbing fiber membrane and a PDMS coating, and the optical plastic substrate, the light absorbing fiber membrane and the PDMS coating are arranged in sequence from bottom to top;

[0011] Or the photoacoustic transducer layer includes a carbon nanotube fiber mesh and a PDMS coating, the optical plastic substrate, the carbon nanotube fiber mesh and the PDMS coating are arranged in sequence from bottom to top, a discontinuous gold nanoparticle layer is arranged on the carbon nanotube fiber mesh, and the gold nanoparticle layer is adjacent to the PDMS coating. Its beneficial effect is that: since precious metal nanoparticles such as gold and silver are most commonly used as photothermal nanomaterials, they effectively absorb light through surface plasmon resonance (LSPR, Localized Surface Plasmon Resonance), and their plasma extinction peak is around 530-560nm, spraying gold nanoparticles on 1 can enhance the absorption of light, thereby achieving the purpose of enhancing the photoacoustic conversion efficiency.

[0012] Preferably, the photoacoustic transducer device is provided with a concave surface for generating focused ultrasound when the laser is incident on the photoacoustic transducer device;

[0013] The concave surface includes at least one of a concave spherical surface, a concave elliptical surface, and a concave irregular shape surface.

[0014] Preferably, the projection of the photoacoustic transducer along the thickness direction is a square with a side length of 0.2-2 mm or a circle with a radius of 0.2-2 mm, the thickness of the optical grade PMMA film is 150-250 μm, the radius of curvature of the arc-shaped pit is 0.5-5 mm, and the depth of the arc-shaped pit is 50-150 μm;

[0015] The photoacoustic transducer layer is a composite film of a light absorbing material and a polymer matrix, the polymer matrix is ​​polydimethylsilane, wherein the thickness of the composite film is 2-10 microns;

[0016] Or the photoacoustic transducer layer includes a light absorbing fiber membrane and a PDMS coating, wherein the optical plastic substrate, the light absorbing fiber membrane and the PDMS coating are arranged in sequence from bottom to top, wherein the thickness of the light absorbing fiber membrane is 2-10 microns, and the thickness of the PDMS coating is 30-50 microns;

[0017] Or the photoacoustic transducer layer includes a carbon nanotube fiber mesh and a PDMS coating, the optical plastic substrate, the carbon nanotube fiber mesh and the PDMS coating are arranged in sequence from bottom to top, and a discontinuous gold nanoparticle layer is arranged on the carbon nanotube fiber mesh, wherein the thickness of the carbon nanotube fiber mesh is 2-12 microns, the layer thickness of the gold nanoparticles is 5-15 nanometers, and the thickness of the PDMS coating is 30-50 microns.

[0018] A method for preparing a photoacoustic transducer device, the photoacoustic transducer device comprising an optical plastic substrate and a photoacoustic transducer layer, the photoacoustic transducer layer being a composite film of multi-walled carbon nanotubes (MWCNT) and polydimethylsilane (PDMS), the optical plastic substrate being an optical grade PMMA film, the method comprising the following steps:

[0019] 1) Surface treatment of MWCNTs;

[0020] 2) uniformly dispersing the surface treated MWCNT in xylene by ultrasonic method to obtain a MWCNT / xylene solution, wherein the ratio of MWCNT to xylene is 5-15 mg / ml;

[0021] 3) mixing the MWCNT / xylene solution and 50-70 wt % PDMS solution at a mass ratio of 0.5-1.5 to obtain a MWCNT / PDMS mixed solution;

[0022] 4) adding a curing agent having a PDMS resin content of 1% to 10% to the MWCNT / PDMS mixed solution, and then mixing and degassing the mixed solution by ultrasonic or orbital stirring;

[0023] 5) The degassing product obtained in step 4) is coated on an optical grade PMMA film by scraping with a scraper, electrostatic spraying, or ultrasonic spraying, and after drying, hot pressing is performed to obtain a double-layer film.

[0024] A method for preparing a photoacoustic transducer device, the photoacoustic transducer device comprising an optical plastic substrate and a photoacoustic transducer layer, the photoacoustic transducer layer comprising a light absorbing fiber membrane and a PDMS coating, the optical plastic substrate, the light absorbing fiber membrane and the PDMS coating being arranged in sequence from bottom to top, the optical plastic substrate being an optical grade PMMA film, the method comprising the following steps:

[0025] 1) Surface treatment of MWCNTs;

[0026] 2) uniformly dispersing the surface treated MWCNT in xylene by ultrasonic method to obtain a MWCNT / xylene solution, wherein the ratio of MWCNT to xylene is 5-15 mg / ml;

[0027] 3) ultrasonically mixing the MWCNT / xylene solution and acetone at a volume ratio of 1:2, and standing at room temperature for 8-12 hours to obtain a MWCNT gel, and low-temperature vacuum drying the MWCNT gel for 24-48 hours to obtain a MWCNT fiber membrane;

[0028] 4) The MWCNT fiber membrane is transferred with smooth PDMS, and the fiber membrane is transferred to an optical grade PMMA film to obtain a double-layer structured combined membrane;

[0029] 5) The double-layer structure bonding membrane is continuously scraped with a scraper, or electrostatic / ultrasonic spraying of PDMS solution is performed, and then dried and solidified; wherein the preparation of the PDMS solution is specifically as follows: PDMS and a curing agent are mixed with a mixture of one or more of acetone, anisole, ethyl acetate, toluene, xylene, etc. to form a mixture, wherein the mass ratio of the curing agent to PDMS is 10%wt, and the mass ratio of the combined weight of the curing agent and PDMS to the mixture is 35%wt-50%wt.

[0030] A method for preparing a photoacoustic transducer device, the photoacoustic transducer device comprising an optical plastic substrate and a photoacoustic transducer layer, the photoacoustic transducer layer comprising a carbon nanotube fiber mesh and a PDMS coating, the optical plastic substrate, the carbon nanotube fiber mesh and the PDMS coating being arranged in sequence from bottom to top, a discontinuous gold nanoparticle layer being arranged on the carbon nanotube fiber mesh, the optical plastic substrate being an optical grade PMMA film, the method comprising the following steps:

[0031] 1) preparing a double-layer structure film combining the carbon nanotube fiber web and the optical grade PMMA film by chemical vapor deposition or polymer dispersion spin coating;

[0032] 2) placing the double-layer structure film into a magnetron sputtering system, and sputtering gold nanoparticles on the carbon nanotube fiber web;

[0033] 3) After completion, use a scraper to apply, or electrostatically / ultrasonically spray the PDMS solution, and then dry and solidify.

[0034] Preferably, the double-layer structure membrane is prepared by a polymer dispersion spin coating method, specifically comprising: adding 30-80wt% hydroxyl-modified carbon nanotubes to a hydroxyethyl cellulose aqueous solution, ultrasonically mixing them evenly, adsorbing an optical-grade PMMA film on a desktop coating machine, dripping the prepared hydroxyethyl cellulose solution of hydroxyl-modified carbon nanotubes on the optical-grade PMMA film, and obtaining the double-layer membrane structure membrane by spin coating and vacuum drying; wherein the hydroxyethyl cellulose aqueous solution contains 0.01%-2wt% hydroxyethyl cellulose, and the solvent is water.

[0035] The method for preparing the photoacoustic transducer device of any technical solution further comprises the steps of:

[0036] The combined film of the optical plastic substrate and the photoacoustic transducer layer is heat-pressed and shaped for a predetermined time using a heatable mold to obtain a photoacoustic device array film, and finally the photoacoustic device array film is cut to obtain a single photoacoustic transducer device.

[0037] Compared with the prior art, the beneficial effects of the present invention are: (1) A plastic substrate with high light transmittance is used, and the plastic substrate is a highly flat optical film, which can reduce light loss and is more suitable for application in the human body than glass. (2) The high light transmittance of the PMMA film makes the photoacoustic conversion efficiency high, and its comprehensive performance is suitable for curved surface modeling. (3) The structural design of the photoacoustic transducer layer, including the thickness design of different layers, balances the various performance requirements of the composite film. (4) The concave design meets the application of focused ultrasound. This type of ultrasound has huge energy at the focus, which is called high-intensity focused ultrasound. The improvement of focused ultrasound can improve the longitudinal resolution of the image. (5) The limited design of multiple dimensions realizes the photoacoustic transducer devices that can meet practical applications in batches. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0039] Figure 1 Schematic diagram of a square photoacoustic transducer device in which the photoacoustic transducer layer is a composite film of a light absorbing material and a polymer matrix in one embodiment of the present invention.

[0040] Figure 2 Schematic diagram of a circular photoacoustic transducer device in which the photoacoustic transducer layer is a composite film of a light absorbing material and a polymer matrix in one embodiment of the present invention.

[0041] Figure 3 Schematic diagram of a square photoacoustic transducer device in which the photoacoustic transducer layer includes a carbon nanotube fiber mesh and a PDMS coating in one embodiment of the present invention.

[0042] Figure 4Schematic diagram of a circular photoacoustic transducer device in which the photoacoustic transducer layer includes a carbon nanotube fiber mesh and a PDMS coating in one embodiment of the present invention.

[0043] Figure 5 This is a schematic diagram of a square photoacoustic transducer device with a discontinuous layer of gold nanoparticles arranged on a carbon nanotube fiber web in one embodiment of the present invention.

[0044] Figure 6 This is a schematic diagram of a circular photoacoustic transducer device having a discontinuous layer of gold nanoparticles arranged on a carbon nanotube fiber web in one embodiment of the present invention. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] A photoacoustic transducer device includes an optical plastic substrate and a photoacoustic transducer layer, wherein the photoacoustic transducer layer is disposed on the optical plastic substrate, and the optical plastic substrate is an optical-grade film with a light transmittance of >85%. The photoacoustic transducer layer can be a multi-layer or a single-layer composite film.

[0047] In some embodiments, the optical plastic substrate is an optical grade PMMA film.

[0048] In some embodiments, the photoacoustic transducer layer is a composite film of a light absorbing material and a polymer matrix, and the polymer matrix is ​​polydimethylsilane;

[0049] Or the photoacoustic transducer layer includes a light absorbing fiber membrane and a PDMS coating, and the optical plastic substrate, the light absorbing fiber membrane and the PDMS coating are arranged in sequence from bottom to top;

[0050] Or the photoacoustic transducer layer includes a carbon nanotube fiber mesh, a PDMS coating, an optical plastic substrate, a carbon nanotube fiber mesh and a PDMS coating are arranged in sequence from bottom to top, a discontinuous gold nanoparticle layer is arranged on the carbon nanotube fiber mesh, and the gold nanoparticle layer is adjacent to the PDMS coating. Since precious metal nanoparticles such as gold and silver are most commonly used as photothermal nanomaterials, they effectively absorb light through surface plasmon resonance (LSPR, Localized Surface Plasmon Resonance), and their plasma extinction peak is around 530-560nm, so spraying gold nanoparticles on 1 can enhance the absorption of light, thereby enhancing the efficiency of photoacoustic conversion.

[0051] In some embodiments, the photoacoustic transducer device is provided with a concave surface for generating focused ultrasound when the laser is incident on the photoacoustic transducer device;

[0052] The concave surface includes at least one of a concave spherical surface, a concave elliptical surface, and a concave irregular surface. In specific use, the concave surface design is suitable for producing focused ultrasound. When the laser hits the concave photoacoustic transducer, focused ultrasound will be generated. This type of ultrasound has huge energy at the focus, which is called high-intensity focused ultrasound. Focused ultrasound can simultaneously improve the longitudinal resolution and lateral resolution of the image, and is very suitable for intravascular ultrasound imaging.

[0053] In some embodiments, the projection of the photoacoustic transducer along the thickness direction is a square with a side length of 0.2-2 mm or a circle with a radius of 0.2-2 mm, the thickness of the optical grade PMMA film is 150-250 μm, the radius of curvature of the arc-shaped pit is 0.5-5 mm, and the depth of the arc-shaped pit is 50-150 μm;

[0054] like Figure 1 and Figure 2 As shown, the photoacoustic transducer layer 1 bonded to the optical grade PMMA film 2 is a composite film of a light-absorbing material and a polymer matrix, the polymer matrix is ​​polydimethylsilane, wherein the thickness of the composite film is 2-10 microns; the light-absorbing materials in the photoacoustic transducer layer 1 include carbon black (CB), candle soot particles (CS), single-walled carbon nanotubes (CNT), multi-walled carbon nanotubes (MWCNT), carbon nanofibers (CNF), reduced graphene oxide (GO), black phosphorus, and halide perovskite.

[0055] or Figure 3 and Figure 4 As shown, the photoacoustic transducer layer includes a light-absorbing fiber membrane 1 and a PDMS coating 3; the optical plastic substrate 2, the light-absorbing fiber membrane 1 and the PDMS coating 3 are arranged in sequence from bottom to top, wherein the thickness of the light-absorbing fiber membrane is 2-10 microns, and the thickness of the PDMS coating is 30-50 microns; the light-absorbing materials in the photoacoustic transducer layer 1 include carbon black (CB), candle soot particles (CS), single-walled carbon nanotubes (CNT), multi-walled carbon nanotubes (MWCNT), carbon nanofibers (CNF), reduced graphene oxide (GO), black phosphorus, and halide perovskite.

[0056] or Figure 5 and Figure 6 As shown, the photoacoustic transducer layer includes a carbon nanotube fiber mesh 1 and a PDMS coating 3; an optical plastic substrate 2, a carbon nanotube fiber mesh 1 and a PDMS coating 3 are arranged in sequence from bottom to top, and a discontinuous gold nanoparticle layer is arranged on the carbon nanotube fiber mesh 1, wherein the thickness of the carbon nanotube fiber mesh is 2-12 microns, the layer thickness of the gold nanoparticles is 5-15 nanometers, and the thickness of the PDMS coating is 30-50 microns.

[0057] A method for preparing a photoacoustic transducer device, the photoacoustic transducer device comprising an optical plastic substrate and a photoacoustic transducer layer, the photoacoustic transducer layer being a composite film of multi-walled carbon nanotubes (MWCNT) and polydimethylsilane (PDMS), the optical plastic substrate being an optical grade PMMA film, in some embodiments, the method specifically comprises the following steps:

[0058] 1) Surface treatment of MWCNTs; the surface treatment steps are as follows: ① 1-pyrenebutyric acid and excess thionyl chloride (SOCl2) are transferred to a round-bottom flask and refluxed at 100°C for 30 minutes. Unreacted SOCl2 was removed by distillation until dry pyrenebutyryl chloride remained; ② Solid pyrenebutyryl chloride was dissolved in dry THF, oleylamine and triethylamine were dissolved in another anhydrous THF, and the pyrenebutyryl chloride solution was added at 0°C; ③ Stirred overnight at room temperature, the product was dissolved in ether and washed with a large amount of water, the organic layer was extracted and dried with sodium sulfate after washing, the ether was evaporated and the product was dried in vacuum at room temperature to obtain oleylamine-functionalized pyrene; ④ MWCNT and oleylamine-functionalized pyrene were dissolved in tetrahydrofuran (THF) in a mass ratio of 1:1 and ultrasonically treated for 5 hours, and all reactions were carried out under Schlenk conditions; ⑤ After ultrasonication, the treated MWCNT was washed with THF at least 5 times to remove the unabsorbed dispersant, and the surface-treated (multi-walled carbon nanotubes) MWCNT were obtained after vacuum drying at room temperature for 24 hours;

[0059] 2) uniformly dispersing the surface treated MWCNT in xylene by ultrasonic method to obtain a MWCNT / xylene solution, wherein the ratio of MWCNT to xylene is 5-15 mg / ml; wherein the ultrasonic time is 10-20 s, and the ultrasonic energy is 72 W;

[0060] 3) Mixing the MWCNT / xylene solution with a 50-70wt% PDMS solution at a mass ratio of 0.5-1.5 to obtain a MWCNT / PDMS mixed solution; wherein the preparation method of the PDMS solution is: mixing 50-70wt% PDMS with a mixture of one or more of acetone, anisole, ethyl acetate, toluene, xylene, etc., and heating and dissolving under appropriate conditions to obtain a PDMS solution;

[0061] 4) After adding a curing agent with a PDMS resin content of 1-10% to the MWCNT / PDMS mixed solution, the solution is mixed evenly and degassed using an ultrasonic or orbiting mixer; the solution is applied using a scraper with a slit width of 80-400 microns, or electrostatically / ultrasonic spraying is applied to an optical-grade PMMA film, and after drying at room temperature for 24 hours, the solution is hot pressed in the next step; wherein the thickness of the optical-grade PMMA film is 170-200 microns;

[0062] 5) The degassing product obtained in step 4) is coated on an optical grade PMMA film by scraping, electrostatic spraying, or ultrasonic spraying, and after drying at room temperature for 24 hours, hot pressing is performed to obtain a double-layer film; wherein the thickness of the optical grade PMMA film is 170-200 microns.

[0063] Furthermore, in some embodiments, the method further comprises the steps of:

[0064] 6) The optical plastic substrate and the photoacoustic transducer layer are combined and hot-pressed for a predetermined time using a heatable mold to obtain a photoacoustic device array film, and finally the photoacoustic device array film is cut to obtain a single photoacoustic transducer device. Figure 1 and Figure 2 As shown, it can be made into a square or a circle according to actual applications.

[0065] A method for preparing a photoacoustic transducer device, the photoacoustic transducer device comprising an optical plastic substrate and a photoacoustic transducer layer, the photoacoustic transducer layer comprising a light absorbing fiber membrane and a PDMS coating, the optical plastic substrate, the light absorbing fiber membrane and the PDMS coating being arranged in sequence from bottom to top, the optical plastic substrate being an optical grade PMMA film, in some embodiments, the method specifically comprises the following steps:

[0066] 1) Surface treatment of MWCNTs: The surface treatment steps are as follows: ① 1-pyrenebutyric acid and excess thionyl chloride (SOCl2) were transferred to a round-bottom flask and refluxed at 100°C for 30 minutes. Unreacted SOCl2 was removed by distillation until dry pyrenebutyryl chloride remained; ② Solid pyrenebutyryl chloride was dissolved in dry THF, oleylamine and triethylamine were dissolved in another anhydrous THF, and the pyrenebutyryl chloride solution was added at 0°C; ③ Stirred overnight at room temperature, the product was dissolved in ether and washed with a large amount of water, the organic layer was extracted and dried with sodium sulfate after washing, the ether was evaporated and the product was dried in vacuum at room temperature to obtain oleylamine-functionalized pyrene; ④ MWCNT and oleylamine-functionalized pyrene were dissolved in tetrahydrofuran (THF) in a mass ratio of 1:1 and ultrasonically treated for 5 hours, and all reactions were carried out under Schlenk conditions; ⑤ After ultrasonication, the treated MWCNT was washed with THF at least 5 times to remove the unabsorbed dispersant, and the surface-treated (multi-walled carbon nanotubes) MWCNT were obtained after vacuum drying at room temperature for 24 hours;

[0067] 2) uniformly dispersing the surface treated MWCNT in xylene by ultrasonic method to obtain a MWCNT / xylene solution, wherein the ratio of MWCNT to xylene is 5-15 mg / ml; wherein the ultrasonic time is 10-20 s, and the ultrasonic energy is 72 W;

[0068] 3) ultrasonically mixing the MWCNT / xylene solution and acetone at a volume ratio of 1:2, and standing at room temperature for 12 hours to obtain a MWCNT gel, and then low-temperature vacuum drying the MWCNT gel for 48 hours to obtain a MWCNT fiber membrane;

[0069] 4) The MWCNT fiber membrane is transferred with smooth PDMS, and the fiber membrane is transferred to an optical grade PMMA film to obtain a double-layer structured combined membrane;

[0070] 5) The double-layer structure bonding film is continuously coated with a scraper, or electrostatically / ultrasonically sprayed with a PDMS solution, and then dried and solidified; wherein the preparation of the PDMS solution is specifically as follows: PDMS is mixed with 10wt% of a curing agent, and after the mixture is evenly mixed with 35-50wt% of one or a mixture of acetone, anisole, ethyl acetate, toluene, xylene, etc., and the PDMS solution can be obtained by heating and dissolving under appropriate conditions;

[0071] Furthermore, in some embodiments, the method further comprises the steps of:

[0072] 6) The optical plastic substrate and the photoacoustic transducer layer are combined and hot-pressed for a predetermined time using a heatable mold to obtain a photoacoustic device array film, and finally the photoacoustic device array film is cut to obtain a single photoacoustic transducer device. Figure 3 and Figure 4 As shown, it can be made into a square or a circle according to actual applications.

[0073] A method for preparing a photoacoustic transducer device, the photoacoustic transducer device comprising an optical plastic substrate and a photoacoustic transducer layer, the photoacoustic transducer layer comprising a carbon nanotube fiber mesh and a PDMS coating, the optical plastic substrate, the carbon nanotube fiber mesh and the PDMS coating being arranged in sequence from bottom to top, a discontinuous gold nanoparticle layer being arranged on the carbon nanotube fiber mesh, the optical plastic substrate being an optical grade PMMA film, and in some embodiments, the method specifically comprising the following steps:

[0074] 1) A double-layer structure film combining a carbon nanotube fiber net and an optical-grade PMMA film is prepared by a polymer dispersion spin coating method; 30-80wt% hydroxyl-modified carbon nanotubes are added to a hydroxyethyl cellulose aqueous solution, and after ultrasonic mixing, the optical-grade PMMA film is adsorbed on a desktop sizing machine, and the prepared hydroxyethyl cellulose solution of hydroxyl-modified carbon nanotubes is dripped onto the film, first rotated at 500 rpm for 20 seconds, and then spin-coated at 200 rpm for 60 seconds, and after spin coating, vacuum dried at 50° C. for 24 hours to obtain a double-layer membrane structure; wherein the hydroxyethyl cellulose aqueous solution contains 0.01-2wt% hydroxyethyl cellulose, and the solvent is water;

[0075] 2) placing the above double-layer structure film into a magnetron sputtering system, sputtering gold nanoparticles on the carbon nanotube fiber net, the purity of the gold target used for sputtering is 99.99%, the vacuum degree of the chamber is 10-2Pa, the target-substrate distance is 5cm, the nano-gold particles are deposited, the deposition rate is 14nm / min, the sputtering time is 45s, and the gold nanoparticle layer is obtained;

[0076] 3) After completion, use a scraper to scrape or electrostatically / ultrasonically spray the PDMS solution, and then dry and solidify; after completion, continue to scrape with a 80-400 micron scraper, or electrostatically / ultrasonically spray the PDMS solution, flash dry at room temperature for 10 minutes, put it in an 80°C oven to dry for 10 minutes, and then put it in a 100°C oven to cure for 35 minutes;

[0077] Furthermore, in some embodiments, the method further comprises the steps of:

[0078] 4) The three layers of film bonded together are heated to 150°C with a heatable mold and hot-pressed for 2 minutes to obtain a photoacoustic device array, and finally the array is cut with a laser cutter to obtain a single photoacoustic transducer device. Figure 6 As shown, it can be made into a square or a circle according to actual applications.

[0079] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A photoacoustic transducer device, characterized in that: The optical plastic substrate comprises an optical plastic substrate and a photoacoustic transducer layer. The photoacoustic transducer layer is arranged on the optical plastic substrate. The optical plastic substrate is an optical-grade film with a light transmittance greater than 85%.

2. The photoacoustic transducer device according to claim 1, characterized in that: The optical plastic substrate is an optical grade PMMA film.

3. The photoacoustic transducer device according to claim 2, characterized in that: The photoacoustic transducer layer is a composite film of a light absorbing material and a polymer matrix, and the polymer matrix is ​​polydimethylsilane; Or the photoacoustic transducer layer includes a light absorbing fiber membrane and a PDMS coating, and the optical plastic substrate, the light absorbing fiber membrane and the PDMS coating are arranged in sequence from bottom to top; Or the photoacoustic transducer layer includes a carbon nanotube fiber mesh and a PDMS coating, the optical plastic substrate, the carbon nanotube fiber mesh and the PDMS coating are arranged in sequence from bottom to top, a discontinuous gold nanoparticle layer is arranged on the carbon nanotube fiber mesh, and the gold nanoparticle layer is adjacent to the PDMS coating.

4. The photoacoustic transducer device according to claim 2, characterized in that: The photoacoustic transducer device is provided with a concave surface for generating focused ultrasound when laser light is incident on the photoacoustic transducer device; The concave surface includes at least one of a concave spherical surface, a concave elliptical surface, and a concave irregular shape surface.

5. The photoacoustic transducer device according to claim 4, characterized in that: The projection of the photoacoustic transducer along the thickness direction is a square with a side length of 0.2-2 mm or a circle with a radius of 0.2-2 mm, the thickness of the optical-grade PMMA film is 150-250 μm, the radius of curvature of the arc-shaped pit is 0.5-5 mm, and the depth of the arc-shaped pit is 50-150 μm; The photoacoustic transducer layer is a composite film of a light absorbing material and a polymer matrix, the polymer matrix is ​​polydimethylsilane, wherein the thickness of the composite film is 2-10 microns; Or the photoacoustic transducer layer includes a light absorbing fiber membrane and a PDMS coating, wherein the optical plastic substrate, the light absorbing fiber membrane and the PDMS coating are arranged in sequence from bottom to top, wherein the thickness of the light absorbing fiber membrane is 2-10 microns, and the thickness of the PDMS coating is 30-50 microns; Or the photoacoustic transducer layer includes a carbon nanotube fiber mesh and a PDMS coating, the optical plastic substrate, the carbon nanotube fiber mesh and the PDMS coating are arranged in sequence from bottom to top, and a discontinuous gold nanoparticle layer is arranged on the carbon nanotube fiber mesh, wherein the thickness of the carbon nanotube fiber mesh is 2-12 microns, the layer thickness of the gold nanoparticles is 5-15 nanometers, and the thickness of the PDMS coating is 30-50 microns.

6. A method for preparing a photoacoustic transducer device, characterized in that: The photoacoustic transducer device comprises an optical plastic substrate and a photoacoustic transducer layer, wherein the photoacoustic transducer layer is a composite film of multi-walled carbon nanotubes (MWCNT) and polydimethylsilane (PDMS), and the optical plastic substrate is an optical grade PMMA film. The method comprises the following steps: 1) Surface treatment of MWCNTs; 2) uniformly dispersing the surface treated MWCNT in xylene by ultrasonic method to obtain a MWCNT / xylene solution, wherein the ratio of MWCNT to xylene is 5-15 mg / ml; 3) mixing the MWCNT / xylene solution with a 50-70 wt % PDMS solution at a mass ratio of 0.5-1.5 to obtain a MWCNT / PDMS mixed solution; 4) adding a curing agent having a PDMS resin content of 1-10% to the MWCNT / PDMS mixed solution, and then mixing and degassing the mixed solution by ultrasonic or orbital stirring; 5) The degassing product obtained in step 4) is coated on an optical grade PMMA film by scraping with a scraper, electrostatic spraying, or ultrasonic spraying, and after drying, hot pressing is performed to obtain a double-layer film.

7. A method for preparing a photoacoustic transducer device, characterized in that: The photoacoustic transducer device comprises an optical plastic substrate and a photoacoustic transducer layer, wherein the photoacoustic transducer layer comprises a light absorbing fiber membrane and a PDMS coating, wherein the optical plastic substrate, the light absorbing fiber membrane and the PDMS coating are arranged in sequence from bottom to top, and the optical plastic substrate is an optical grade PMMA film. The method comprises the following steps: 1) Surface treatment of MWCNTs; 2) uniformly dispersing the surface treated MWCNT in xylene by ultrasonic method to obtain a MWCNT / xylene solution, wherein the ratio of MWCNT to xylene is 5-15 mg / ml; 3) ultrasonically mixing the MWCNT / xylene solution and acetone at a volume ratio of 1:2, and standing at room temperature for 8-12 hours to obtain a MWCNT gel, and low-temperature vacuum drying the MWCNT gel for 24-48 hours to obtain a MWCNT fiber membrane; 4) The MWCNT fiber membrane is transferred with smooth PDMS, and the fiber membrane is transferred to an optical grade PMMA film to obtain a double-layer structured combined membrane; 5) The double-layer structure bonding membrane is continuously scraped with a scraper, or electrostatic / ultrasonic spraying of PDMS solution is performed, and then dried and solidified; wherein the preparation of the PDMS solution is specifically as follows: PDMS and a curing agent are mixed with a mixture of one or more of acetone, anisole, ethyl acetate, toluene, xylene, etc. to form a mixture, wherein the mass ratio of the curing agent to PDMS is 10%wt, and the mass ratio of the combined weight of the curing agent and PDMS to the mixture is 35%wt-50%wt.

8. A method for preparing a photoacoustic transducer device, characterized in that: The photoacoustic transducer device comprises an optical plastic substrate and a photoacoustic transducer layer, wherein the photoacoustic transducer layer comprises a carbon nanotube fiber mesh and a PDMS coating, wherein the optical plastic substrate, the carbon nanotube fiber mesh and the PDMS coating are arranged in sequence from bottom to top, a discontinuous gold nanoparticle layer is arranged on the carbon nanotube fiber mesh, and the optical plastic substrate is an optical grade PMMA film. The method comprises the following steps: 1) preparing a double-layer structure film combining the carbon nanotube fiber web and the optical grade PMMA film by chemical vapor deposition or polymer dispersion spin coating; 2) placing the double-layer structure film into a magnetron sputtering system, and sputtering gold nanoparticles on the carbon nanotube fiber web; 3) After completion, use a scraper to apply, or electrostatically / ultrasonically spray the PDMS solution, and then dry and solidify.

9. The preparation method according to claim 8, characterized in that: The double-layer structure membrane is prepared by a polymer dispersion spin coating method, specifically comprising: adding 30-80wt% hydroxyl-modified carbon nanotubes to a hydroxyethyl cellulose aqueous solution, ultrasonically mixing them evenly, adsorbing an optical-grade PMMA film on a desktop sizing machine, dripping the prepared hydroxyethyl cellulose solution of hydroxyl-modified carbon nanotubes on the optical-grade PMMA film, and obtaining the double-layer membrane structure membrane by spin coating and vacuum drying; wherein the hydroxyethyl cellulose aqueous solution contains 0.01-2wt% hydroxyethyl cellulose, and the solvent is water.

10. The method for preparing a photoacoustic transducer device according to any one of claims 6 to 9, characterized in that: Also includes the steps: The combined film of the optical plastic substrate and the photoacoustic transducer layer is heat-pressed and shaped for a predetermined time using a heatable mold to obtain a photoacoustic device array film, and finally the photoacoustic device array film is cut to obtain a single photoacoustic transducer device.

Images