Graphdiyne film-based light response execution system and motion control method thereof
By generating controllable displacement motion under illumination using a self-supporting graphdiyne film, the problem of reversible floating and sinking and trajectory navigation of actuators in open liquid environments is solved, realizing a simplified control method and highly stable motion.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INST OF CHEM CHINESE ACAD OF SCI
- Filing Date
- 2026-02-09
- Publication Date
- 2026-06-19
Smart Images
Figure CN122239733A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of photoresponse execution technology, specifically relating to a photoresponse execution system based on a graphdiyne thin film and its motion control method. Background Technology
[0002] Non-contact actuation and motion control of movable actuators in open liquid environments can be used in scenarios such as interface regulation, mixing enhancement, and local mass transfer regulation. Compared with micro-nano particles or packaged devices, thin-film actuators with millimeter to centimeter scale have relatively simple structures, are easier to manufacture and manipulate, are suitable for direct manipulation in open containers, and the motion process is easy to visualize and record, which is beneficial for achieving large displacements and repeatable motion.
[0003] Existing motion control solutions in liquid environments commonly include magnetic field drive, electric field drive, acoustic field drive, and mechanical traction. These solutions typically require the introduction of magnetic components or the configuration of electrodes and wires, dedicated acoustic devices, and mechanical clamping structures, making the system structure relatively complex. In open liquid systems, these solutions may be affected by media adaptability, boundary conditions, and device layout. Especially when simultaneously achieving reversible buoyancy switching of the actuator and planar navigation along a preset trajectory, control stability and repeatability still need improvement.
[0004] Therefore, there is a need to provide a simplified, non-mechanically contactless, and suitable membrane actuator system and its motion control method for operation in open liquid environments, so as to realize the controllable motion of the actuator and take into account the control requirements such as reversible floating and sinking and trajectory navigation, thereby meeting the application requirements of convenient operation and repetitive operation. Summary of the Invention
[0005] The purpose of this invention is to provide a photoresponsive actuator system and its motion control method based on a graphdiyne film, which enables a self-supporting graphdiyne film to generate controllable displacement motion in a liquid medium under illumination, thereby realizing reversible floating and sinking control as well as two-dimensional directional motion and trajectory following on the liquid surface. Furthermore, three-dimensional displacement regulation can be achieved through phased control of the height adjustment stage and the two-dimensional navigation stage on the liquid surface.
[0006] The photoresponse actuation system based on graphyne thin film provided by the present invention includes:
[0007] (1) Container; (2) A liquid medium disposed within the container; (3) A self-supporting graphdiyne film body serving as a photoresponse actuator, wherein the self-supporting graphdiyne film body is disposed in the liquid medium; (4) A light source, located outside the container, is used to provide local illumination to the graphdiyne film body area, thereby heating the film body and inducing a buoyancy convection flow field and / or Marangoni effect in the liquid medium, thus driving the film body to move. (5) Irradiation area adjustment mechanism, used to adjust the irradiation area of the local light on the film body so that the local light area overlaps with the film body at least partially, and to achieve directional motion control by changing the offset of the irradiation area relative to the geometric center of the film body.
[0008] The light source provides localized illumination to the graphyne film body, which locally raises the temperature of the self-supporting graphyne film body, thereby inducing a buoyancy convection flow field in the liquid medium and / or generating an interface-driven effect (Marangoni effect) caused by the temperature gradient near the liquid surface, driving the film body to produce displacement motion.
[0009] The irradiation area adjustment mechanism is used to adjust the irradiation area of the local light on the film body, so that the local light irradiation area at least partially overlaps with the film body, and by changing the offset direction and offset amount of the local light irradiation area relative to the geometric center of the film, the directional movement, turning and path following of the film body in the liquid surface can be realized.
[0010] The thickness of the graphdiyne film body can be 9-11 μm; The graphdiyne film body is a spherical film with a diameter of 5-15 mm; The liquid medium has low viscosity, a large coefficient of thermal expansion, and a large surface tension temperature coefficient, which is beneficial for forming a stable driving force under local heating; the liquid medium may specifically be an alcohol, more specifically ethanol or methanol; The light source can be a xenon lamp; The incident light power density of the localized illumination is based on the light power density measured by an optical power meter at the bottom plane of the container, and can be 400–1000 mW / cm². 2 Preferably 550–600 mW / cm 2 .
[0011] The direction of the localized illumination is perpendicular to the liquid surface.
[0012] The feature size of the localized illumination region is larger than the feature size of the graphdiyne film body.
[0013] The present invention also provides a motion control method for the system, the motion control method comprising the following steps: (1) The self-supporting graphdiyne film is placed in a liquid medium; (2) Turn on the light to heat up the graphdiyne film and induce a flow field in the liquid medium, driving the graphdiyne film to float to the liquid surface. (3) When the light is turned off, the graphdiyne film body sinks under the action of gravity, thus achieving reversible floating and sinking switching by turning the light on and off; (4) When the graphdiyne film body is on the liquid surface, the irradiation part of the local light on the graphdiyne film body is adjusted so that the center of the irradiation area is offset relative to the geometric center of the film body, thereby driving the film to move in two dimensions along the direction determined by the offset direction, and the trajectory is followed by continuously changing the offset direction according to the preset trajectory.
[0014] In the above method, the motion speed is controlled by adjusting the incident light power density, and the motion speed increases with the increase of the incident light power density; During the floating stage, the illumination area (spot diameter) is preferably 10 times the film diameter; Under the same liquid medium and light conditions, the graphdiyne film body can still operate normally after multiple floating and sinking cycles.
[0015] The preset trajectory can be a straight line, a broken line, a circle, a spiral, or a maze-like path. By continuously changing the bias direction, the photoresponse actuator (self-supporting graphyne film body) can achieve the movement of the corresponding path.
[0016] The motion control includes three-dimensional guidance control, which includes a height adjustment stage and a liquid surface two-dimensional navigation stage. In the height adjustment stage, the graphdiyne film body floats to the liquid surface or sinks away from the liquid surface by means of a light switch. In the liquid surface two-dimensional navigation stage, the graphdiyne film body moves from the starting position to the target position on the liquid surface by adjusting the bias direction of the irradiation part, and can be stationary by maintaining the irradiation part.
[0017] The application of the aforementioned photoresponse actuator based on graphdiyne thin film in motion control scenarios in open liquid environments also falls within the scope of protection of this invention.
[0018] Compared with the prior art, the present invention has the following advantages: the system structure is simple; remote controllable driving can be achieved through the irradiation site and light power density; it has good reversibility and repeatability; and it is suitable for motion control scenarios in open liquid environments. Attached Figure Description
[0019] Figure 1 This is a flowchart illustrating the preparation process of graphdiyne thin films. Figure 2 Photographs of graphyne on copper foil and graphyne films cut into different shapes. Figure 3 Scanning electron microscopy characterization of the prepared graphdiyne film; Figure 4 Raman spectral characterization of the prepared graphdiyne film; Figure 5 This is a schematic diagram of a light-response execution system; Figure 6 This is a schematic diagram of the reversible floating and sinking time sequence; Figure 7 The height-time curve of a reversible floating and sinking process; Figure 8 For reversible floating and sinking repeatability testing; Figure 9 The velocity / time-optical power relationship curve; Figure 10 A schematic diagram defining the offset and a photograph showing horizontal movement; Figure 11 This is a schematic diagram of three-dimensional motion control. Detailed Implementation
[0020] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.
[0021] The invention will now be further described with reference to the accompanying drawings.
[0022] It should be noted that the preparation route of the graphdiyne film can be obtained using existing publicly available methods. This specific embodiment describes in detail the preparation and control process of the photoresponse actuator based on the graphdiyne film.
[0023] The following provides the specific process and parameters for thin film acquisition, processing, and motion control.
[0024] Graphdiyne films can be grown in situ on copper foil substrates using coupling polymerization in a pyridine system: using hexynylbenzene as the monomer and copper foil as the substrate (copper foil thickness and purity can be selected from conventional commercial specifications), the reaction is carried out at 80 °C for 3 days to form a continuous graphdiyne film on the copper foil surface (see...). Figure 1 As an example, 100 mg of hexynylbenzene was added to 200 mL of pyridine, and the reaction under the above conditions yielded a graphdiyne film with a thickness of approximately 10 μm. After the reaction was complete, the copper foil with the film was removed and washed with ethanol to remove residual reactants.
[0025] The above preparation steps can be adjusted according to conventional conditions in the field, and the resulting film can be used in this invention as long as it meets the requirements of self-support and thickness range.
[0026] To obtain a self-supporting graphdiene film, the copper foil with the film can be treated in a hydrochloric acid solution to achieve peeling: preferably, the hydrochloric acid concentration is about 1 M, and the peeling time is about 2 min, so that the graphdiene film detaches from the copper foil substrate. The peeled film is then washed sequentially with deionized water and ethanol to remove residual acid and impurities, and then air-dried or dried at low temperature, thereby obtaining a self-supporting film that can independently maintain its shape after the growth substrate is removed.
[0027] The thickness of the graphdiyne film can be adjusted by the concentration of hexyneylbenzene monomer. In this invention, the film thickness is preferably 9–11 μm, more preferably about 10 μm. Too small a thickness can lead to a decrease in film integrity and operability, while too large a thickness may reduce photoresponse driving efficiency and motion stability.
[0028] The film's dimensions can be customized (see below). Figure 2 The film is preferably processed into a circular shape with a diameter of 5–15 mm, more preferably about 10 mm. If the size is too small, it will be detrimental to stable operation and visual representation, while if the size is too large, it will be susceptible to container boundary effects, which will reduce the stability of path control.
[0029] The morphology and thickness of the thin film were characterized by scanning electron microscopy, and the material fingerprint information was verified by Raman spectroscopy to prove the successful preparation of the graphdiyne thin film. The processed graphdiyne thin film was used as the body of a photoresponsive actuator.
[0030] Construction of the motion control system: Add a liquid medium, preferably anhydrous ethanol, to a transparent container; place the aforementioned photoresponsive actuator in the ethanol. The container can be a square transparent container with an internal length of 20 cm, an internal width of 14 cm, and a height of 16 cm. The liquid level of the added liquid medium is 13 cm. The above container dimensions and liquid depth are examples and do not constitute limitations.
[0031] A xenon lamp is used as the light source to provide illumination, and the illumination direction is preferably perpendicular to the liquid surface. The distance between the fiber optic output end and the bottom plane of the container can be set according to the space of the device, for example, about 17 cm. The characteristic size of the illumination area (the area covered by the light spot) is preferably larger than the characteristic size of the thin film. During the floating stage, the diameter of the light spot is preferably 10 times the diameter of the thin film to reduce the sensitivity of the thin film to the light-receiving state by small positional changes and improve control stability.
[0032] To adapt to different motion control stages, the xenon lamp is guided through an optical fiber to form localized illumination. The fiber optic output end is positioned above the container and aligned with the thin film body area. The output end directly emits light to form a spot, and the size of the spot can be adjusted using focusing optics. The fiber optic output end has both a fixed illumination state and an adjustable illumination position state.
[0033] In the fixed illumination state, the fiber optic output end is fixed directly above the film by a clamping bracket, maintaining vertical incidence and a distance of approximately 17 cm from the output end to the initial position of the film (the film is located at the inner bottom), for reversible buoyancy control. In the irradiation adjustment state, while maintaining an approximately vertical incident direction and a basically constant height, the operator holds the fiber optic output end and translates or fine-tunes its lateral position; this lateral position adjustment is preferably performed in a plane parallel to the liquid surface to maintain a basically constant height of the output end and incident angle. Through the above lateral position adjustment, a controllable bias is generated on the film body by the center of the light spot, thereby adjusting the bias direction and bias amount for two-dimensional directional movement on the liquid surface, path navigation, and the two-dimensional navigation stage in three-dimensional guidance. In both states, the local illumination area at least partially overlaps with the film body to achieve continuous drive. In the floating stage, a larger light spot is preferably used to improve stability; in the two-dimensional navigation stage, a light spot covering the film body and preferably larger than the characteristic size of the film can be used, with the film located in the edge region of the light spot to form asymmetric light reception conditions.
[0034] In addition to ethanol, methanol and other alcoholic liquid media can also be used; the liquid media preferably has low viscosity, large coefficient of thermal expansion, and large surface tension temperature coefficient.
[0035] In this specification, the optical power density is defined as the optical power density measured by an optical power meter at the bottom plane of the container. The optical power density range is 400–1000 mW / cm². 2 More preferably 550–600 mW / cm 2 When the power is too low, it is difficult to form a stable drive; when the power is too high, it may introduce unnecessary heat input and system disturbances, which is detrimental to repeatability and controllability.
[0036] Example 1: Preparation of self-supporting graphdiyne thin films Reference Figure 1Preparation of self-supporting graphyne films: Six copper foils, each 20 cm long and 1.5 cm wide, were prepared and soaked in 3 M dilute hydrochloric acid for 5 min. They were then washed twice each with deionized water, ethanol, and acetone. Under argon protection, 125 mL of pyridine was added to a three-necked flask, followed by the copper foils as the reaction substrate. 100 mg of hexynylbenzene was added to 75 mL of pyridine and dissolved completely with stirring. The solution was then added to the three-necked flask and reacted at 80 °C for 3 days, forming a continuous graphyne film on the copper foil surface. After the reaction, the copper foil with the film was removed and washed with ethanol to remove residual reactants. The copper foil was then placed in a 1 M hydrochloric acid solution for 2 min for peeling treatment to detach the graphyne film from the copper foil substrate. The peeled film was then washed sequentially with deionized water and ethanol to remove residual acid and impurities, and then dried at room temperature for 2 h, thus obtaining a self-supporting film that could independently maintain its shape after the growth substrate was removed. The thickness of the graphyne film was measured to be approximately 10 μm using scanning electron microscopy (see [link to article]). Figure 3 ).
[0037] The graphdiyne film is cut and processed into a circular film with a diameter of 10 mm according to requirements.
[0038] The morphology and thickness of the thin film were characterized by scanning electron microscopy (see [link]). Figure 3 Material fingerprint information is verified using Raman spectroscopy (see...). Figure 4 This proves that the graphdiyne film was successfully prepared. The processed graphdiyne film was used as the body of the photoresponse actuator.
[0039] Example 2: Construction and Motion Control of a Photoresponsive Execution System Reference Figure 5 A photoresponsive actuator system was constructed as follows: Anhydrous ethanol (≥99.7%) was added as the liquid medium to a square transparent container (20 cm inner length, 14 cm inner width, and 16 cm height), with the liquid level at 13 cm. The graphyne film prepared in Example 1 was placed in the anhydrous ethanol as the photoresponsive actuator. The container was not sealed, and the initial experimental temperature was room temperature (25 °C). A xenon lamp was used as the light source, with the illumination direction perpendicular to the liquid surface. The distance between the fiber optic output end and the bottom plane of the container was approximately 17 cm. The xenon lamp light was directed through the fiber optic cable to form localized illumination. The fiber optic output end was positioned above the container and aligned with the film body area, directly emitting light to form a spot. The size of the light spot could be adjusted using focusing optics. The fiber optic output end had both a fixed illumination state and an adjustable illumination position.
[0040] In the fixed illumination state, the fiber optic output end is fixed directly above the film by a clamping bracket, maintaining vertical incidence and a distance of approximately 17 cm from the output end to the initial position of the film (the film is located at the inner bottom), for reversible buoyancy control. In the irradiation adjustment state, while maintaining an approximately vertical incident direction and a substantially constant height, the operator holds the fiber optic output end and translates or fine-tunes its lateral position. This lateral position adjustment is performed in a plane parallel to the liquid surface to maintain a substantially constant height and incident angle. Through this lateral position adjustment, a controllable bias is generated between the light spot center and the film body, thereby adjusting the bias direction and amount for two-dimensional directional movement on the liquid surface, path navigation, and the two-dimensional navigation stage in three-dimensional guidance. In both states, the localized illumination area at least partially overlaps with the film body to achieve continuous drive. A larger light spot is used in the floating stage to improve stability; in the two-dimensional navigation stage, a light spot covering the film body and larger than the film's characteristic size is used, with the film located at the edge of the light spot to create asymmetric illumination conditions.
[0041] The optical power density is based on the optical power density measured by the optical power meter at the bottom plane of the container, and is 550–600 mW / cm². 2 The diameter of the light spot during the ascent phase is approximately 10 cm, and the diameter of the light spot during the two-dimensional navigation phase is approximately 4 cm.
[0042] During the reversible buoyancy control phase, the fiber optic output end maintains the aforementioned fixed irradiation state. When the illumination is turned on, the actuator locally heats up and induces a flow field in the ethanol, causing the actuator to float from the liquid interior to the surface. When the illumination is turned off, the induced flow field weakens or even disappears, causing the actuator to sink back to the bottom of the liquid, thus achieving reversible buoyancy control. The entire process is recorded on video, and key frames are extracted to form a timing diagram (see...). Figure 6 Simultaneously, the change in actuator center height over time was recorded and a height-time curve was plotted (see...). Figure 7 ), used to characterize response time and displacement process.
[0043] At a fixed power (598 mW / cm) 2 Multiple on-off light cycles were performed, and the repeatability test results were obtained by superimposing or statistically analyzing multiple sets of height-time curves. The reversibility and repeatability of the floating-sinking process were verified through 38 on-off cycles. Each cycle included turning the light on until the film reached the liquid surface, then turning it off; turning it off until the film returned to the bottom, then turning it on again. A complete cycle was defined as the film rising from the bottom of the liquid to the surface and sinking back to the bottom after the light was turned off. The changes in rising and sinking times during each of the 38 consecutive cycles were statistically analyzed to characterize repeatability (see...). Figure 8 ).
[0044] To achieve velocity control, buoyancy experiments were repeated under different incident light power densities. Height-time data were recorded, and the buoyancy velocity and time to reach the liquid surface were calculated, thus obtaining the velocity / time-light power relationship curve (see...). Figure 9 ).
[0045] When the thin film is locally heated by light, a temperature gradient and a density gradient are formed inside the liquid, generating buoyancy convection. At the same time, a temperature gradient is formed near the liquid surface, causing the surface tension to be unevenly distributed along the liquid surface. This results in a shear flow (Marangoni effect) driven by the surface tension gradient near the liquid surface. The two work together to drive the movement of the thin film.
[0046] In the two-dimensional directional motion and path navigation control on a liquid surface, the film is first guided to the liquid surface under a fixed illumination state. Then, the illumination is switched to an adjustment state, maintaining at least partial overlap between the illuminated area and the film body. The illumination point on the film body is changed by manually translating or fine-tuning the fiber optic output end, causing a controllable offset between the light spot center and the film's geometric center, thereby adjusting the offset direction and amount. Here, "offset" refers to the lateral displacement of the light spot center relative to the film's geometric center within the liquid surface plane, and "offset direction" refers to the direction of this displacement. The directional motion direction of the film is controlled by the offset direction; changing the offset direction achieves steering and preset path following. By adjusting the offset direction and amount, the light intensity distribution at different parts of the film can be changed, inducing an asymmetric flow field, thereby driving the film to generate in-plane displacement and achieving steering and path following (see...). Figure 10 ).
[0047] The target path is pre-defined as a straight line, a broken line, a circle, a spiral, or a maze. The direction of movement is controlled by the bias direction, which continuously changes the bias direction of the illumination center on the thin film over time, causing the actuator to move continuously towards the target direction. Turning is achieved in real time by changing the bias direction of the illumination, thus enabling navigation along spiral and maze paths. The above control method relies on continuous illumination of the thin film body to prevent the actuator from losing drive outside the illuminated area.
[0048] In three-dimensional motion control, a phased control process of "floating—surfacing—arrival and dwelling—descent" is achieved. Specifically, a three-dimensional target is set, from the starting position A (e.g., the bottom of the liquid) to the target position B (e.g., a target area on the liquid surface): First, during the height adjustment phase, illumination is turned on to locally heat the actuator and induce a flow field, thereby causing it to float from A to the liquid surface. Subsequently, during the two-dimensional navigation phase on the liquid surface, the illumination is kept continuously and at least partially overlapped with the thin film body. By adjusting the offset direction and amount of the illumination center on the thin film, the actuator moves along a preset two-dimensional path from the liquid surface projection starting point A′ to the liquid surface endpoint B. When the actuator reaches the target area, the offset amount can be reduced to near zero or to a preset threshold to achieve position holding, or the illumination can be turned off to cause it to sink from the liquid surface, thus completing the three-dimensional guidance control closed loop (see...). Figure 11 ).
[0049] The present invention has been described in detail above. Those skilled in the art will recognize that the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. While specific embodiments have been provided, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope disclosed herein.
Claims
1. A photoresponse actuator based on a graphyne thin film, comprising: (1) Container; (2) A liquid medium disposed within the container; (3) A self-supporting graphdiyne film body serving as a photoresponse actuator, wherein the self-supporting graphdiyne film body is disposed in the liquid medium; (4) A light source, located outside the container, is used to provide local illumination to the graphdiyne film body area, thereby heating the film body and inducing a buoyancy convection flow field and / or Marangoni effect in the liquid medium, thus driving the film body to move. (5) Irradiation area adjustment mechanism, used to adjust the irradiation area of the local light on the film body so that the local light area overlaps with the film body at least partially, and to achieve motion control by changing the offset of the irradiation area relative to the geometric center of the film body.
2. The optical response execution system according to claim 1, characterized in that, The irradiation area adjustment mechanism is used to adjust the irradiation area of the local light on the film body, so that the local light irradiation area at least partially overlaps with the film body, and by changing the offset direction and offset amount of the local light irradiation area relative to the geometric center of the film, the directional movement, turning and path following of the film body in the liquid surface can be realized.
3. The optically responsive execution system according to claim 1, characterized in that, The thickness of the graphdiyne film is 9-11 μm.
4. The optical response execution system according to claim 1, characterized in that, The liquid medium has low viscosity, a large coefficient of thermal expansion, and a large surface tension temperature coefficient. The liquid medium may specifically be an alcohol.
5. The optical response execution system according to claim 1, characterized in that, The light source is a xenon lamp; The incident light power density of the localized illumination, measured by an optical power meter at the bottom plane of the container, is 400–1000 mW / cm². 2 .
6. The optical response execution system according to claim 1, characterized in that, The direction of the localized illumination is perpendicular to the liquid surface; The feature size of the localized illumination region is larger than the feature size of the graphdiyne film body.
7. The motion control method of the optical response actuation system according to any one of claims 1-6, comprising the following steps: (1) The self-supporting graphdiyne film is placed in a liquid medium; (2) Turn on the light to heat up the graphdiyne film and induce a flow field in the liquid medium, driving the graphdiyne film to float to the liquid surface. (3) When the light is turned off, the graphdiyne film body sinks under the action of gravity, thus achieving reversible floating and sinking switching by turning the light on and off; (4) When the graphdiyne film body is on the liquid surface, the irradiation part of the local light on the graphdiyne film body is adjusted so that the center of the irradiation area is offset relative to the geometric center of the film body, thereby driving the film to move in two dimensions along the direction determined by the offset direction, and the trajectory is followed by continuously changing the offset direction according to the preset trajectory.
8. The method according to claim 7, characterized in that, In the method, the motion speed is controlled by adjusting the incident light power density, and the motion speed increases with the increase of the incident light power density. During the ascent phase, the illuminated area (spot diameter) is 10 times the diameter of the thin film; Under the same liquid medium and light conditions, the graphdiyne film body can still operate normally after multiple floating and sinking cycles.
9. The method according to claim 7, characterized in that, The preset trajectory can be a straight line, a broken line, a circle, a spiral, or a maze-like path. By continuously changing the bias direction, the photoresponse actuator (self-supporting graphyne film body) can achieve the movement of the corresponding path. The motion control includes three-dimensional guidance control, which includes a height adjustment stage and a liquid surface two-dimensional navigation stage. In the height adjustment stage, the graphdiyne film body floats to the liquid surface or sinks away from the liquid surface by means of a light switch. In the liquid surface two-dimensional navigation stage, the graphdiyne film body moves from the starting position to the target position on the liquid surface by adjusting the bias direction of the irradiation part, and can be stationary by maintaining the irradiation part.
10. The application of the photoresponse actuator based on graphdiyne thin film according to any one of claims 1-6 in motion control scenarios in open liquid environments.