Method for observing photo-thermal driven micro-nano structure deformation under in-situ electron microscope
By adding photothermal components to liquid crystal elastomers and combining them with scanning electron microscopes and laser devices, the problem of in-situ driving and observation of micro-nano structures under high vacuum conditions in SEM has been solved, realizing high-precision dynamic deformation observation of micro-nano structures and promoting the development of nanoelectromechanical systems.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-10
- Publication Date
- 2026-03-10
AI Technical Summary
Existing technologies make it difficult to achieve in-situ driving and high-precision observation of micro and nanostructures in the high-vacuum sealed environment of scanning electron microscopes (SEM). Liquid crystal elastomers are prone to image distortion under electron beam irradiation, and optical microscopes have low resolution, making it difficult to capture fine deformations at the nanoscale.
Photothermal components are added to liquid crystal elastomers. By combining scanning electron microscopes (SEMs) and laser devices, photothermal drive is achieved in the vacuum chamber of an SEM using lasers. The dynamic deformation of micro- and nano-structures is observed through SEMs. A five-axis precision displacement stage is used to adjust the incident angle and position of the laser to ensure high-precision observation.
It enables reliable and controllable deformation observation of micro and nanostructures under high pressure vacuum conditions, obtains clear SEM images, and realizes in-situ real-time observation of the entire process from stimulus to response to observation at the same location, supporting in-depth exploration of the driving mechanism of smart materials at the nanoscale.
Smart Images
Figure CN121632029A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of micro-nano fabrication and smart materials technology, specifically involving an in-situ electron microscope observation method for photothermal-driven micro-nano structure deformation. Background Technology
[0002] Controllable actuation and motion at the micro- and nano-scale are core technologies in cutting-edge fields such as micro- and nano-robotics and biotechnology. Among related technologies, the observation of the driving behavior of micro- and nano-structures based on liquid crystal elastomers mostly relies on optical microscopy techniques such as confocal microscopy. However, this type of method has obvious limitations: (1) It is difficult to capture fine deformation and structural changes at the hundred-nanometer level due to the optical diffraction limit and small depth of field. Moreover, it requires the use of "Z-axis stacking" to synthesize full-focus images, which is cumbersome. (2) At present, in the high-vacuum closed observation environment such as scanning electron microscope (SEM), it is not possible to effectively integrate in-situ driving functions, and it is difficult to use the high resolution and large depth of field of scanning electron microscope (SEM) to achieve in-situ real-time observation at the nanoscale. In addition, as an insulator, liquid crystal elastomer will accumulate charge due to electron beam irradiation when directly observed by SEM, resulting in image distortion and blurring. It is difficult to accurately capture the details of micro- and nano-structures and driving behavior, which further limits the application of SEM. Therefore, it is urgent to develop a high-precision micro- and nano-structure driving observation technology suitable for in-situ electron microscope. Summary of the Invention
[0003] This application aims to at least partially address one of the technical problems in related technologies. To this end, this application proposes an in-situ observation method for photothermal driven micro / nano structures. This method can clearly and continuously observe the dynamic deformation process and morphological evolution of micro / nano structures under photothermal driving, realizing the integration of driving and observation.
[0004] The first aspect of this application proposes an in-situ observation method for photothermally driven micro / nano structures, including: A liquid crystal elastomer is provided, the liquid crystal elastomer comprising a photothermal component; Micro- and nanostructures are fabricated from the liquid crystal elastomer; A scanning electron microscope and a laser device are provided, wherein a sample stage for supporting the micro / nano structure is provided in the vacuum chamber of the scanning electron microscope; The laser device includes a laser generator and an output conical lens fiber. The output conical lens fiber is connected to the laser generator and is used to transmit and focus the laser generated by the laser generator. The output conical lens fiber is disposed in the vacuum cavity and is used to irradiate the micro / nano structure with laser. The micro / nano structure is irradiated with a laser beam of predetermined wavelength and power, and the dynamic deformation of the micro / nano structure is observed using a scanning electron microscope.
[0005] This application overcomes the key technologies of effectively introducing and precisely controlling photothermal excitation by adding photothermal components to liquid crystal elastomers and combining scanning electron microscopy with a laser device. This ensures that micro / nanostructures can achieve reliable and controllable microscale deformation under high-pressure vacuum conditions, obtaining clear SEM images of the micro / nanostructures and enabling in-situ real-time observation of the dynamic deformation process. This method is safe, reliable, and parameter-adjustable, without damaging the micro / nanostructure. It achieves the entire process from "stimulus" to "response" to "observation" in the same time and location (in-situ), providing a crucial platform for in-depth exploration of the driving mechanisms of smart materials at the nanoscale and promoting the development of next-generation nanoelectromechanical systems (NEMS).
[0006] According to embodiments of this application, the photothermal component includes gold nanoparticles, which are uniformly dispersed within the polymer network of the liquid crystal elastomer. This enables good electrical conductivity and photothermal actuation, facilitating in-situ real-time observation of the dynamic deformation process of the micro / nano structure under SEM.
[0007] According to an embodiment of this application, the laser generator is a continuously output semiconductor laser, and the predetermined wavelength is 800nm-1100nm. Therefore, within this range, light energy can be efficiently converted into heat energy, causing a rapid increase in local temperature and driving the deformation of the micro / nano structure without damaging it.
[0008] According to an embodiment of this application, the laser beam has a laser spot diameter of 3µm-10µm. Therefore, within this range, the microstructure region to be observed can be precisely covered, allowing for accurate targeting and driving of a specific microstructure within the micro / nano structure.
[0009] According to an embodiment of this application, when laser-induced deformation of the micro / nanostructure is used, the predetermined power is 4mW-50mW. Therefore, within this range, observable deformation of the micro / nanostructure can be ensured while avoiding damage to the micro / nanostructure and interference with observation.
[0010] According to an embodiment of this application, the predetermined wavelength is determined through the following steps: Measure the absorption spectrum of the liquid crystal elastomer; Based on the absorption spectrum, the wavelength corresponding to the maximum absorbance of the photothermal component in the liquid crystal elastomer is determined. The wavelength corresponding to the absorption peak is set to the predetermined wavelength.
[0011] According to embodiments of this application, observing the dynamic deformation of the micro / nano structure includes: Before the laser is turned on, the initial morphology image of the micro / nano structure is captured and recorded using the scanning electron microscope; Timing begins the instant the laser is turned on, and the scanning electron microscope continuously captures dynamic deformation images of the micro / nano structure over a specific time period, which is less than or equal to 180 seconds.
[0012] According to an embodiment of this application, a five-axis precision displacement stage is further provided in the vacuum cavity of the scanning electron microscope. The output conical lens fiber is provided on the five-axis precision displacement stage for adjusting the focusing position and laser emission angle of the laser, so that the laser output by the laser generator irradiates the surface of the micro-nano structure at a predetermined incident angle.
[0013] According to an embodiment of this application, during the laser irradiation of the micro / nano structure for 30s-180s, the bending angle of the micro / nano structure is 30°-40°, and the lateral displacement of the end of the micro / nano structure is 3.0μm-4.2μm. Therefore, by precisely controlling the laser irradiation time, accurate and continuous control of the final deformation state of the micro / nano structure can be achieved.
[0014] According to embodiments of this application, the laser irradiates the surface of the micro / nano structure at a predetermined incident angle of 0°-90°. Therefore, by adjusting the incident angle, various deformation patterns can be achieved, improving the flexibility of photothermal driving. Attached Figure Description
[0015] Figure 1 This is a deformation diagram of the micro / nano structure observation process in Embodiment 1 of this application.
[0016] Figure 2 This is the absorption spectrum of the liquid crystal elastomer of Embodiment 1 of this application. Detailed Implementation
[0017] The embodiments of this application are described in detail below, with examples of these embodiments illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.
[0018] Controllable actuation and motion at the micro- and nano-scale are core technologies in cutting-edge fields such as micro- and nano-robotics and biotechnology. Among various actuation methods, photothermal actuation has attracted widespread attention due to its outstanding advantages such as wireless remote control, non-contact operation, and high spatiotemporal resolution. In related technologies, the observation of the actuation behavior of micro- and nano-structures mainly relies on optical microscopy techniques, such as confocal microscopy. However, this type of method has significant limitations: First, limited by the optical diffraction limit, its resolution is low, making it difficult to accurately capture the fine deformation processes and subtle structural changes at scales of hundreds of nanometers and below; second, optical microscopes have a small depth of field, usually requiring the use of "Z-axis stacking" techniques to synthesize full-focus images, which is cumbersome and time-consuming; third, in-situ actuation functions cannot be integrated into the high-vacuum, closed observation environment of scanning electron microscopy (SEM), making it difficult to utilize the high resolution and large depth of field advantages of SEM to achieve in-situ real-time observation of nanoscale actuation behavior.
[0019] Against this backdrop, this application proposes a high-precision micro / nanostructure driving observation technique suitable for in-situ electron microscopy in a scanning electron microscope (SEM) vacuum environment. By adding photothermal components to a liquid crystal elastomer and combining an SEM with a laser device, this application overcomes the key technologies for the effective introduction and precise control of photothermal excitation. This ensures that the micro / nanostructure can achieve reliable and controllable microscale deformation under high-pressure vacuum conditions, obtaining clear SEM images of the micro / nanostructure. This enables in-situ real-time observation and allows for direct visualization of the dynamic deformation process of the micro / nanostructure. This method is safe, reliable, and parameter-adjustable, without damaging the micro / nanostructure. It achieves the entire process from "stimulus" to "response" to "observation" in the same time and location (in-situ), providing a crucial platform for in-depth exploration of the driving mechanisms of smart materials at the nanoscale and promoting the development of next-generation nanoelectromechanical systems (NEMS).
[0020] The first aspect of this application proposes an in-situ observation method for photothermal driven micro / nano structures, comprising the following steps: S10: Provide a liquid crystal elastomer, the liquid crystal elastomer comprising a photothermal component.
[0021] The core function of the photothermal component is as a highly efficient "nanoscale heater." Uniformly dispersed within the LCE network, it strongly absorbs light energy and rapidly converts it into heat when irradiated with light of a specific wavelength, causing a sharp increase in the local temperature of itself and the surrounding LCE material. At low temperatures, the internal liquid crystal units of the LCE are in a highly ordered "nematic phase." When the temperature rises above a critical point (clearing point), the order of the liquid crystal units is disrupted, transforming into a disordered "isotropic phase." During this phase transition from order to disorder, the average length of the liquid crystal units shortens (because the extended conformation required to maintain an ordered arrangement is no longer necessary). Since these liquid crystal units are chemically linked to the polymer network through crosslinking agents, this shortening causes the entire polymer network to macroscopically shrink along the liquid crystal orientation direction, while the liquid crystal elastomer may expand in the direction perpendicular to the orientation. If the micro / nanostructure design is asymmetrical, this anisotropic shrinkage / expansion can lead to reversible, large-amplitude bending, twisting, and other deformations, achieving photothermal drive.
[0022] According to embodiments of this application, the photothermal component includes gold nanoparticles, which are uniformly dispersed within the polymer network of the liquid crystal elastomer. This enables good electrical conductivity and photothermal actuation, facilitating in-situ real-time observation of the dynamic deformation process of the micro / nano structure under SEM.
[0023] The preparation process of the liquid crystal elastomer in this application follows conventional methods. As a specific example, the preparation process is as follows: In a yellow light environment (wavelength range of 570nm-590nm), liquid crystal basic material, crosslinking agent, hydrated tetrachloroauric acid (HAuCl4·3H2O), and liquid crystal monomer are added sequentially and stirred evenly to obtain a mixture; the above mixture is stirred at 70℃-90℃ for 1h-1.5h, a photoinitiator is added to the system, the temperature is lowered to 50℃-60℃, and stirring is continued for 1h-1.5h, finally obtaining a transparent liquid crystal elastomer, which is then placed in a brown bottle and dried at room temperature for storage.
[0024] The principle behind obtaining gold-containing liquid crystal elastomers is as follows: When a laser is precisely focused onto the liquid crystal elastomer, the photoinitiator is excited to a high-energy state through a two-photon absorption process. The excited-state initiator plays a dual role: on the one hand, it decomposes to generate free radicals, initiating a free radical polymerization reaction between the liquid crystal monomers and the crosslinking agent; the liquid crystal monomers are linked by chemical bonds to form long-chain polymers, and the crosslinking agent crosslinks these long chains into a three-dimensional elastomer network (i.e., the matrix of the liquid crystal elastomer); on the other hand, it acts as a reducing agent, directly transferring its high-energy electrons to chloroaurate ions ([AuCl4)). - Au in ) 3+ Au 3+After gaining electrons, the gold atoms are reduced to an unstable intermediate valence state and rapidly generate zero-valent gold atoms (i.e., gold nanoparticles) through pathways such as disproportionation reactions. The in-situ generated gold nanoparticles are then encapsulated within the forming elastomer network. As the polymerization reaction completes, the gold nanoparticles are stably fixed within the polymer network of the liquid crystal elastomer, ultimately yielding a liquid crystal elastomer containing gold nanoparticles.
[0025] For example, the crosslinking agent includes at least one of pentaerythritol triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol hexaacrylate.
[0026] For example, the initiator includes at least one of 7-diethylamino-3-thiophenecarboxycoumarin, 2-isopropylthioxanthonone, and 2,4-diethylthioxanthonone.
[0027] For example, the liquid crystal cell material includes at least one of 4-methoxybenzoic acid 4-(6-acryloyloxyhexyl)phenyl ester, 1,4-bis(4-(6-acryloyloxyhexyl)benzoyloxy)-2-methylbenzene, 1,4-bis-[4-(3-acryloyloxypropoxy)benzoyloxy]-2-methylbenzene, and 4-((6-(acryloyloxy)hexyl)oxy)phenyl 4-((6-(acryloyloxy)hexyl)oxy)benzoate.
[0028] For example, the liquid crystal monomer includes at least one of 4-pentyl-4'-cyanobiphenyl, 4-butyl-4'-cyanobiphenyl, and 4-cyano-4'-ethylbiphenyl.
[0029] S20: Micro-nano structures are prepared from the liquid crystal elastomer.
[0030] As a specific example, the method for fabricating micro / nano structures from the liquid crystal elastomer is as follows: A substrate (such as quartz glass) is provided and cleaned; a three-dimensional structural model is created using computer 3D modeling software, and motion trajectory codes for laser printing are generated; the aforementioned liquid crystal elastomer is printed layer-by-layer on the substrate using a femtosecond laser-based two-photon polymerization direct-writing system, with a laser wavelength of 515 nm, a power of 2.0 mW-3.5 mW, a pulse duration of <300 fs, a repetition frequency of 44 MHz, and a processing speed of 1 m / s-2 m / s. Development is performed at room temperature using a developer (such as propylene glycol methyl ether acetate PGMEA, isopropanol IPA, etc.) for 5 min-20 min, ultimately obtaining the micro / nano structure.
[0031] In this application, micro-nano structures refer to structured units with feature sizes ranging from hundreds of nanometers to micrometers, prepared using liquid crystal elastomers as raw materials and through micro-nano processing technology.
[0032] S30: Provides a scanning electron microscope and a laser device, wherein a sample stage for supporting the micro / nano structure is provided in the vacuum chamber of the scanning electron microscope; The laser device includes a laser generator and an output conical lens fiber. The output conical lens fiber is connected to the laser generator and is used to transmit and focus the laser generated by the laser generator. The output conical lens fiber is disposed in the vacuum cavity and is used to irradiate the micro-nano structure with laser.
[0033] In this step, the scanning electron microscope (SEM) overcomes the limitations of traditional optical microscopes due to its high resolution (capturing nanoscale microstructures) and large depth of field (fully presenting the three-dimensional morphology of microstructures). The coordinated design of the laser device and the SEM allows for precise control of laser activation and real-time electron imaging, ensuring in-situ real-time observation and recording of the deformation process of micro / nano structures, as well as recording clear and complete changes in micro / nano structures.
[0034] According to an embodiment of this application, a five-axis precision displacement stage is further provided within the vacuum chamber of the scanning electron microscope. The output conical lens fiber is mounted on the five-axis precision displacement stage for adjusting the focusing position and laser emission angle of the laser, ensuring that the laser beam output from the laser generator irradiates the surface of the micro / nano structure at a predetermined incident angle. Thus, by utilizing the adjustment function of the five-axis precision displacement stage, the spatial position of the output conical lens fiber and the laser emission angle can be flexibly adjusted, ultimately ensuring that the laser beam output from the laser generator can irradiate the surface of the micro / nano structure, providing optimal laser interaction conditions for laser-driven deformation of the micro / nano structure and subsequent observation.
[0035] The five-axis precision displacement stage in this application is a high-precision positioning device with five degrees of freedom of motion capability. It is mainly used to accurately control the spatial attitude and position of a load (such as a laser focusing lens). Its "five axes" correspond to translational adjustment along the three linear coordinate axes X, Y, and Z, as well as rotational adjustment around the X and Y axes.
[0036] S40: Irradiate the micro / nano structure with a laser of predetermined wavelength and power, and observe the dynamic deformation of the micro / nano structure using the scanning electron microscope.
[0037] In this step, the micro / nano structure is placed on the sample stage. Based on the photothermal response characteristics of the liquid crystal elastomer, the laser generator is determined and adjusted, the corresponding wavelength is selected, the output power of the laser is adjusted and the laser is turned on. The laser induces the micro / nano structure to deform, and then the dynamic deformation of the micro / nano structure is recorded by the scanning electron microscope.
[0038] According to embodiments of this application, before fixing the micro / nano structure onto the sample stage of the scanning electron microscope, the method further includes: depositing a layer of conductive metal film on the surface of the micro / nano structure. The thickness of the conductive metal film is 5nm-30nm, specifically within the range of 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, or any two thereof. This enhances the conductivity of the micro / nano structure, which is beneficial for uniform imaging.
[0039] According to embodiments of this application, the material of the metal conductive film includes, but is not limited to, gold.
[0040] According to an embodiment of this application, the predetermined wavelength is determined through the following steps: Measure the absorption spectrum of the liquid crystal elastomer; Based on the absorption spectrum, the wavelength corresponding to the maximum absorbance of the photothermal component in the liquid crystal elastomer is determined. The wavelength corresponding to the absorption peak is set to the predetermined wavelength.
[0041] Therefore, when the laser wavelength is precisely matched to the absorption peak, it can ensure that the photothermal components generate heat efficiently and drive the deformation of micro and nano structures stably, while avoiding damage to the micro and nano structures caused by excess laser energy (such as degradation of liquid crystal elastomers due to overheating). At the same time, the stable photothermal conversion process can keep the deformation of micro and nano structures uniform, and with the high-resolution observation of scanning electron microscope, deformation details can be captured more clearly.
[0042] According to an embodiment of this application, the laser generator is a continuously output semiconductor laser, and the predetermined wavelength is 800nm-1100nm, specifically such as 800nm, 808nm, 810nm, 850nm, 900nm, 980nm, 1000nm, 1100nm, or any range between two of them. Therefore, within the above range, light energy can be efficiently converted into heat energy, causing a rapid increase in local temperature and driving the deformation of the micro / nano structure without damaging it.
[0043] According to embodiments of this application, the laser spot diameter is 3µm-10µm, specifically 3µm, 5µm, 10µm, or any range between two of these. Therefore, within this range, the microstructure region to be observed can be precisely covered, accurately targeting and driving a specific microstructure within the micro / nano structure, thereby achieving targeted excitation of local structural deformation.
[0044] It is understandable that the output power of the laser generator has a significant impact on the observation process. The principle for setting the output power is: sufficient to induce visible deformation in the micro / nano structure, while avoiding excessive power that could cause ablation or microstructural damage to the polymer material due to overheating. The specific power value used in actual observations can be adjusted according to the photosensitivity of the LCE material used.
[0045] According to embodiments of this application, when laser-induced deformation of the micro / nanostructure is used, the predetermined power is 4mW-50mW, specifically such as 4mW, 5mW, 10mW, 15mW, 25mW, 30mW, 35mW, 40mW, 45mW, 50mW, or any range between two of these. Within this range, the photothermal components efficiently absorb energy and convert it into heat, rapidly bringing the liquid crystal elastomer to the "clearing point" temperature required for phase transition. This ensures observable deformation of the microstructure while avoiding damage to the micro / nanostructure and interference with observation.
[0046] According to embodiments of this application, observing the dynamic deformation of the micro / nano structure includes: Before the laser is turned on, the initial morphology image of the micro / nano structure is captured and recorded using the scanning electron microscope; Timing begins the instant the laser is turned on, and the scanning electron microscope continuously captures dynamic deformation images of the micro / nano structure over a specific time period, which is less than or equal to 180 seconds.
[0047] Thus, the initial image can clearly show the original state of the micro-nano structure when it is not driven by laser, and the deformation observed later can be directly compared with the initial state to accurately quantify the degree of deformation (such as bending angle).
[0048] According to an embodiment of this application, during the laser irradiation of the micro / nano structure for 30s-180s, the bending angle of the micro / nano structure is 30°-40°, and the lateral displacement of the end of the micro / nano structure is 3.0μm-4.2μm. Therefore, by precisely controlling the laser irradiation time, accurate and continuous control of the final deformation state of the micro / nano structure can be achieved.
[0049] In this paper, the "bending angle of the micro / nano structure" refers to the angle between the tangent of the centerline at the fixed root of the structure and the initial axial direction in the SEM image. When the change in the effective driving length of the structure is negligible, this angle can be approximated by arctan(end-end lateral displacement / structure projected height).
[0050] "The lateral displacement of the end of a micro / nano structure" refers to the horizontal displacement of the free end of the structure relative to its initial straight state after bending. It can be obtained by observing the two-dimensional projection image of the micro / nano structure using a scanning electron microscope (SEM) and measuring it using image analysis software.
[0051] According to embodiments of this application, the laser irradiates the surface of the micro / nano structure at a predetermined incident angle of 0°-90°. Therefore, by adjusting the incident angle, various deformation patterns can be achieved, improving the flexibility of photothermal driving.
[0052] The embodiments of this application are described in detail below.
[0053] Example 1 In a yellow light environment, 75% wt of 4-methoxybenzoic acid 4-(6-acryloyloxyhexyl)phenyl ester, 20% wt of 1,4-bis(4-(6-acryloyloxyhexyl)benzoyloxy-2-methylbenzene), 2 wt% crosslinking agent (pentaerythritol triacrylate), 0.5 wt% tetrachloroauric acid hydrate, and liquid crystal monomer (4-pentyl-4'-cyanobiphenyl) were added sequentially to a flask to obtain a mixture. The mixture was stirred at room temperature for 6 h, then the temperature was raised to 80 °C, and the initiator pentaerythritol triacrylate was added and stirring was continued for 1 h. Finally, a transparent liquid crystal elastomer was obtained, which was placed in a brown bottle and dried at room temperature for storage.
[0054] A three-dimensional structural model was created using computer 3D modeling software, and motion trajectory codes for laser printing were generated. At 25°C, the liquid crystal elastomer was printed layer by layer on quartz glass using a femtosecond laser-based two-photon polymerization direct writing system to obtain a micro-nano structure. The specific parameters are as follows: laser wavelength is 515nm, power is 2.5mw, pulse is 300fs, and repetition frequency is 44MHz.
[0055] The absorption spectra of the above-mentioned liquid crystal elastomers are shown in the figure. Figure 2 As shown in the figure, the wavelength corresponding to the maximum absorbance of the gold nanoparticles is 980 nm. Therefore, 980 nm is determined as the output wavelength of the laser generator. With the laser generator output power at 10 mW, at a wavelength of 980 nm, and a scanning electron microscope voltage of 3 kV, the above micro / nano structure was irradiated with a laser beam, and significant deformation was observed. The specific deformation process is described in [reference needed]. Figure 1 Before turning on the laser, refer to... Figure 1 In the left image, the aforementioned micro / nano structure is in an extended state. When the laser beam is turned on, as shown in the reference image... Figure 1 As shown in the right image, the liquid crystal elastomer has undergone significant deformation, changing from a vertical shape to a bent state. The bending angle of the micro / nano structure is 30°, and the lateral displacement at the end is 3.0 μm. The principle behind this deformation process is as follows: when irradiated with a laser, the liquid crystal elastomer in the micro / nano structure absorbs energy and converts it into heat energy. The liquid crystal units change from an ordered orientation to a disordered state, causing the structure to change from a vertical state to a bent state.
[0056] Comparative Example 1 Similar to Example 1, except that hydrated tetrachloroauric acid was not added, resulting in a liquid crystal elastomer without photothermal components. The micro / nano structure of this liquid crystal elastomer was observed using the observation method described in Example 1, and no deformation was observed.
[0057] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0058] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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 of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0059] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0060] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.
Claims
1. A method for in-situ observation of optothermally driven micro-nano structures, characterized in that, The application relates to a method for observing dynamic deformation of a micro-nano structure. The method comprises the following steps: Providing a liquid crystal elastomer, wherein the liquid crystal elastomer comprises a photothermal component; Preparation of the micro-nano structure from the liquid crystal elastomer; Providing a scanning electron microscope and a laser device, wherein a sample stage for carrying the micro-nano structure is arranged in a vacuum chamber of the scanning electron microscope; The laser device comprises a laser generator and an output tapered lens optical fiber connected to the laser generator, which is used for transmitting and focusing the laser generated by the laser generator; the output tapered lens optical fiber is arranged in the vacuum chamber and is used for laser irradiation of the micro-nano structure; 2. The observation method according to claim 1, characterized by, Irradiating the micro-nano structure with a laser of a predetermined wavelength and a predetermined power, and observing the dynamic deformation of the micro-nano structure by the scanning electron microscope.
3. The observation method according to claim 1, characterized by, The photothermal component comprises gold nanoparticles uniformly dispersed in the polymer network of the liquid crystal elastomer. The predetermined wavelength is determined by the following steps: Measuring the absorption spectrum of the liquid crystal elastomer; According to the absorption spectrum, the wavelength corresponding to the maximum absorbance of the photothermal component in the liquid crystal elastomer is determined; 4. The observation method according to claim 1, characterized by, The wavelength corresponding to the absorption peak is set as the predetermined wavelength.
5. The method of claim 1, wherein, The laser generator is a continuous output semiconductor laser, and the predetermined wavelength is 800-1100 nm.
6. The method of claim 1, wherein, The laser spot diameter of the laser is 3-10 microns.
7. The observation method according to claim 1, characterized by, When the laser is used to induce deformation of the micro-nano structure, the predetermined power is 4-50 mW. The observation of the dynamic deformation of the micro-nano structure comprises the following steps: Before the laser is turned on, the initial topography image of the micro-nano structure is captured and recorded by the scanning electron microscope; 8. The observation method according to claim 1, characterized by, Timing starts at the moment when the laser is turned on, and the dynamic deformation image of the micro-nano structure is continuously captured by the scanning electron microscope for a specific time, which is less than or equal to 180 seconds.
9. The observation method according to claim 1, characterized by, A five-axis precision displacement stage is further arranged in the vacuum chamber of the scanning electron microscope, and the output tapered lens optical fiber is arranged on the five-axis precision displacement stage, which is used for adjusting the focusing position and the laser exit angle of the laser, so that the laser beam output by the laser generator is incident on the surface of the micro-nano structure at a predetermined incident angle.
10. The method of observing of claim 1, wherein, The laser is incident on the surface of the micro-nano structure at a predetermined incident angle of 0-90 degrees. Between 30 seconds and 180 seconds of laser irradiation of the micro-nano structure, the bending angle of the micro-nano structure is 30-40 degrees, and the lateral displacement of the end of the micro-nano structure is 3.0-4.2 microns.