阅读说明：本技术 微纳米马达的运动方法和微纳米马达定向运动模型 (Motion method of micro-nano motor and micro-nano motor directional motion model ) 是由 胡小文 李森 董任峰 周国富 于 2021-07-14 设计创作，主要内容包括：本发明公开了微纳米马达的运动方法和微纳米马达定向运动模型。微纳米马达的运动方法包括以下步骤：将微纳米马达分散于主体液晶中；向微纳米马达施加光照,使微纳米马达在主体液晶中自热泳；向主体液晶施加电压,改变主体液晶的取向,从而带动微纳米马达的运动方向的定向转动。向微纳米马达施加光照,使得微纳米马达产生自热泳。在这种情况下,微纳米马达在主体液晶中运动到需改变其运动方向的位置时,通过主体液晶两侧的电压改变主体液晶的取向方向,并在主体液晶转向的带动下,微纳米马达的运动方向发生偏转,以此来控制其在自热泳下的定向运动。(The invention discloses a motion method of a micro-nano motor and a micro-nano motor directional motion model. The motion method of the micro-nano motor comprises the following steps: dispersing the micro-nano motor in main liquid crystal; applying light to the micro-nano motor to enable the micro-nano motor to perform self-thermophoresis in the main liquid crystal; and applying voltage to the main liquid crystal to change the orientation of the main liquid crystal so as to drive the micro-nano motor to rotate directionally in the motion direction. And applying light to the micro-nano motor to enable the micro-nano motor to generate self-thermophoresis. Under the condition, when the micro-nano motor moves to a position where the movement direction of the micro-nano motor needs to be changed in the main liquid crystal, the orientation direction of the main liquid crystal is changed through the voltage on two sides of the main liquid crystal, and the movement direction of the micro-nano motor is deflected under the driving of the turning direction of the main liquid crystal, so that the orientation movement of the micro-nano motor under the self-heating swimming is controlled.)

1. The motion method of the micro-nano motor is characterized by comprising the following steps of:

dispersing the micro-nano motor in main liquid crystal;

applying light to the micro-nano motor to enable the micro-nano motor to perform self-thermophoresis in the main liquid crystal;

and applying voltage to the main liquid crystal to change the orientation of the main liquid crystal so as to drive the micro-nano motor to rotate directionally in the motion direction.

2. The exercise method of claim 1, wherein the voltage is an alternating voltage.

3. The exercise method of claim 1, wherein the micro-nano motor comprises microspheres and a photo-thermal material layer, and the photo-thermal material layer is asymmetrically distributed on the surfaces of the microspheres.

4. The exercise method of claim 3, wherein the layer of photothermal material is a layer of Au.

5. The exercise method according to claim 3, wherein the micro-nano motor is thiol-modified micro-nano motor.

6. The exercise method according to claim 1, wherein the absorption peak of the micro-nano motor is between 760nm and 1400 nm.

7. The exercise method according to claim 1, wherein the micro-nano motor has a diameter of 10nm to 100 μm.

8. The motion method according to any one of claims 1 to 7, wherein the host liquid crystal is a positive liquid crystal.

9. Micro-nano motor directional movement model, its characterized in that includes:

a liquid crystal cell comprising two conductive substrates and a bulk liquid crystal encapsulated between the two conductive substrates, the two conductive substrates for applying a voltage to the bulk liquid crystal to change an orientation of the bulk liquid crystal;

the micro-nano motor is dispersed in the main liquid crystal and can perform self-thermophoresis under the stimulation of illumination.

10. The micro-nano motor directional motion model of claim 9, wherein the bulk liquid crystal is a forward liquid crystal.

Technical Field

The application relates to the technical field of micro-nano motors, in particular to a motion method and a directional motion model of the micro-nano motor.

Background

The existing micro-nano motors can be roughly divided into two types, one is a micro-nano motor driven by fuel, and the other is a micro-nano motor driven by external stimulation. The fuel-driven micro-nano motor can generate energy to drive the micro-nano motor to move through catalytic reaction on fuels such as hydrogen peroxide, hydrazine or organic dye. The external field driving micro-nano motor can generate driving force to the micro-nano motor by taking ultrasound, a magnetic field, heat and the like as external stimulation. However, both of the two modes have randomness of movement in a three-dimensional direction, that is, directional movement of the micro-nano motor cannot be realized, which greatly limits the practical application of the micro-nano motor.

Disclosure of Invention

The present application is directed to solving at least one of the problems in the prior art. Therefore, the application provides a motion method of the micro-nano motor, and the method can realize directional motion of the micro-nano motor.

The application also aims to provide a micro-nano motor directional motion model.

In a first aspect of the present application, a method for moving a micro-nano motor is provided, which includes the following steps:

dispersing the micro-nano motor in main liquid crystal;

applying light to the micro-nano motor to enable the micro-nano motor to perform self-thermophoresis in the main liquid crystal;

and applying voltage to the main liquid crystal to change the deflection of the main liquid crystal so as to drive the micro-nano motor to rotate directionally in the motion direction.

The exercise method according to the embodiment of the application has at least the following beneficial effects:

light is applied to the micro-nano motor, and light energy is absorbed by virtue of the plasma resonance effect to generate resonance and is converted into heat to be released. Due to the asymmetry of the micro-nano motor, the heat is released asymmetrically, and a higher temperature gradient field appears near the micro-nano motor, so that the micro-nano motor generates self-thermophoresis. Under the condition, when the micro-nano motor moves to a position where the movement direction of the micro-nano motor needs to be changed in the main liquid crystal, the deflection direction and the angle of the main liquid crystal are changed through the voltage on the two sides of the main liquid crystal, and the movement direction of the micro-nano motor is deflected under the driving of the turning direction of the main liquid crystal, so that the directional movement of the micro-nano motor under the self-heating swimming is controlled.

In some embodiments of the present application, the voltage is an alternating voltage. By applying alternating voltage, the switches of the voltages on the two sides are repeatedly operated to realize the continuous deflection of the main liquid crystal so as to change the motion direction of the microsphere motor; meanwhile, the remote instant 'moving' and 'stopping' of the micro-nano motor are realized through the instantaneous switch of illumination. The two aspects are combined to realize the precise control of the directional motion of the micro-nano motor.

It will be appreciated that any liquid crystal material which optionally has an orientation rotation under an electric field may be used as the host liquid crystal.

In some embodiments of this application, micro-nano motor includes microballon and light and heat material layer, and the light and heat material layer can produce certain temperature gradient around micro-nano motor through the light and heat conversion of light and heat material layer under this kind of asymmetric distribution makes the illumination condition to the light and heat conversion of micro-nano motor takes place from thermophoresis.

In some embodiments of the present application, the photothermal material layer is an Au layer. Au has good photo-thermal effect and can be formed on the surface of the microsphere by magnetron sputtering and other methods.

In some embodiments of the present application, the micro-nano motor is a thiol-modified micro-nano motor. The thiol modification enables the micro-nano motor to have better dispersibility, can be better dispersed in the main liquid crystal without agglomeration, and is beneficial to reducing the viscous resistance of the micro-nano motor in the main liquid crystal.

In some embodiments of the present application, the absorption peak of the micro-nano motor is between 760nm and 1400 nm. When the absorption peak of the micro-nano motor is between 760nm and 1400nm, the micro-nano motor can perform directional motion through near-infrared illumination.

In some embodiments of the present application, the micro-nano motor has a diameter of 10nm to 100 μm.

In some embodiments of the present application, the host liquid crystal is a positive liquid crystal.

The second aspect of the application provides micro-nano motor directional motion model, includes:

a liquid crystal cell including two conductive substrates and a bulk liquid crystal, the bulk liquid crystal being encapsulated between the two conductive substrates, the two conductive substrates being for applying a voltage to the bulk liquid crystal to change a deflection of the bulk liquid crystal;

the micro-nano motor is dispersed in the main liquid crystal and can perform self-thermophoresis under the stimulation of illumination.

According to this application embodiment's micro-nano motor directional movement model, at least, following beneficial effect has:

the self-thermophoresis phenomenon can be generated after light is applied to the micro-nano motor. Under the condition, when the micro-nano motor moves to a position where the movement direction of the micro-nano motor needs to be changed in the main liquid crystal, the orientation direction of the main liquid crystal is changed by applying voltage to two sides of the main liquid crystal, and the movement direction of the micro-nano motor is deflected under the driving of the turning direction of the main liquid crystal, so that the orientation movement of the micro-nano motor under the self-heating swimming is controlled.

In some embodiments of the present application, the host liquid crystal is a forward liquid crystal.

Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.

Drawings

Fig. 1 is a schematic structural diagram of a micro-nano motor prepared in embodiment 1 of the present application.

FIG. 2 is a schematic cross-sectional view of a liquid crystal cell according to an embodiment of the present application, when not powered and when powered.

Fig. 3 is a schematic diagram illustrating a principle that a micro-nano motor of an embodiment of the present application performs directional motion in a liquid crystal cell.

Reference numerals: microspheres 110, a photo-thermal material layer 120, a first conductive layer 211, a first substrate layer 212, a second conductive layer 221, a second substrate layer 222, a host liquid crystal 230, and a power supply 240.

Detailed Description

The conception and the resulting technical effects of the present application will be clearly and completely described below in conjunction with the embodiments to fully understand the objects, features and effects of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all embodiments, and other embodiments obtained by those skilled in the art without inventive efforts based on the embodiments of the present application belong to the protection scope of the present application.

The following detailed description of embodiments of the present application is provided for the purpose of illustration only and is not intended to be construed as a limitation of the application.

In the description of the present application, the meaning of a plurality is one or more, the meaning of a plurality is two or more, and the above, below, exceeding, etc. are understood as excluding the present number, and the above, below, within, etc. are understood as including the present number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description of the present application, unless otherwise expressly limited, terms such as set, mounted, connected and the like should be construed broadly, and those skilled in the art can reasonably determine the specific meaning of the terms in the present application by combining the detailed contents of the technical solutions.

In the description of the present application, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Referring to fig. 1, a structure of a micro-nano motor in an embodiment of the present application is shown, the micro-nano motor includes microspheres 110 and a photo-thermal material layer 120, and the photo-thermal material layer 120 is asymmetrically distributed on the surfaces of the microspheres 110. Through the asymmetric distribution, when the micro-nano motor receives light, heat generated by photothermal conversion of the photothermal material layer 120 on the surface of the microsphere 110 is not completely and uniformly distributed at different positions, so that a certain temperature gradient is generated. In this case, the micro-nano motor may generate self-thermophoresis due to the Soret effect (Soret effect), and the speed of the self-thermophoresis has a direct relationship with the temperature gradient. In some embodiments, gold (Au) with good photo-thermal effect is used as the material of the photothermal material layer 120 to improve the efficiency of the autophoresis. Other photothermal materials known to those skilled in the art, such as Pb, CuS, etc., can be used as the material for the photothermal material layer. In some embodiments, the photo-thermal material layer 120 is asymmetrically distributed on the surface of the microsphere 110 at one side of the microsphere 110, and the micro-nano motor is simpler in preparation process when the distribution mode is adopted. It is understood that any other asymmetric distribution on the surface of the microsphere 110 can also bring about gradient distribution of the thermal field and make the micro-nano motor generate self-thermophoresis. Similarly, besides the microspheres, other photo-thermal materials with asymmetric distribution on the surface of the micro-nano motor in different shapes such as dumbbell shape, snowman shape, rod shape, cake shape and the like can also bring about inhomogeneous distribution of the thermal field and cause the micro-nano motor to generate self thermophoresis.

Referring to fig. 2, a structure of a liquid crystal cell including first and second conductive substrates on both sides in one embodiment of the present application is shown. A bulk liquid crystal 230 is encapsulated between the first conductive substrate and the second conductive substrate. In some embodiments, the first conductive substrate comprises a first conductive layer 211 and a first substrate layer 212, and the second conductive substrate comprises a second conductive layer 221 and a second substrate layer 222. The first and second conductive substrates may be in communication with a power supply 240 to apply a voltage to the bulk liquid crystal enclosed in the liquid crystal cell. Referring to fig. 2 (a) and (b), (a) being the liquid crystal cell with power off and (b) being the liquid crystal cell after power on, which maintains an orientation in substantially one direction when there is no voltage across the bulk liquid crystal. When the power is on, voltage is generated on two sides of the main liquid crystal, so that the main liquid crystal generates directional rotation.

Referring to fig. 3, an embodiment of the present application provides a method for moving a micro-nano motor. The method comprises the following steps: as shown in (a), the micro-nano motor is dispersed in the bulk liquid crystal 230; by combining the (a) and the (b), after light is applied to the micro-nano motor, heat generated by photo-thermal conversion of the photo-thermal material layer 120 on the surface of the microsphere 110 is distributed incompletely and uniformly at different positions, so that a certain temperature gradient is generated, and the micro-nano motor can generate an autophoresis phenomenon and move towards a certain direction; as shown in (c), when the micro-nano motor moves to a specific position, the power supply 240 applies a voltage to the main liquid crystal 230 through the first conductive layer 211 and the second conductive layer 221 to change the orientation of the main liquid crystal 230, and further drive the micro-nano motor to rotate, so that the gradient thermal field around the micro-nano motor changes, and the movement direction of the micro-nano motor rotates directionally, as shown in (c) and (d), the precise control of the directional movement of the micro-nano motor under the self-heating electrophoresis is realized.

In some embodiments, the power supply is an ac power supply, ac voltage is applied to two sides of the main liquid crystal through the ac power supply, and the deflection angle of the main liquid crystal is continuously changed by using ac power with appropriate intensity, so as to control the precise directional motion of the micro-nano motor. In some embodiments, the host liquid crystal is a liquid crystal material that is optionally oriented under a power plant. In some specific embodiments, in order to improve the dispersion degree of the micro-nano motor in the main liquid crystal and reduce the viscous resistance of the micro-nano motor in the main liquid crystal, the micro-nano motor can be modified to a certain degree. In some preferred embodiments, the modification is a thiol modification. In some embodiments, the micro-nano motor has a diameter ranging from a few nanometers to hundreds of micrometers, preferably from 10nm to 100 μm. In some specific embodiments, the absorption peak of the micro-nano motor is between 760nm and 1400nm, so that the micro-nano motor can perform directional motion by near-infrared illumination. In some preferred embodiments, the host liquid crystal is a positive liquid crystal. When the positive liquid crystal is used as a main liquid crystal material, the micro-nano motor can obtain better dispersibility, so thiol can not be used for modification.

The embodiment of the present application further provides a micro-nano motor directional movement model, and this micro-nano motor directional movement model includes: a liquid crystal cell including two conductive substrates and a bulk liquid crystal, the bulk liquid crystal being enclosed between the two conductive substrates, the two conductive substrates being for applying a voltage to the bulk liquid crystal to change an orientation of the bulk liquid crystal; the micro-nano motor is dispersed in the main liquid crystal and can perform self-thermophoresis under the stimulation of illumination. The self-thermophoresis phenomenon can be generated after light is applied to the micro-nano motor. Under the condition, when the micro-nano motor moves to a position where the movement direction of the micro-nano motor needs to be changed in the main liquid crystal, the orientation direction of the main liquid crystal is changed by applying voltage to two sides of the main liquid crystal, and the movement direction of the micro-nano motor is deflected under the driving of the turning direction of the main liquid crystal, so that the orientation movement of the micro-nano motor under the self-heating swimming is controlled. In some of these embodiments, the host liquid crystal is a forward liquid crystal.

The present application is further illustrated by the following specific examples.

Example 1

The embodiment provides a micro-nano motor, and the preparation process of the micro-nano motor is as follows:

(1) taking a proper amount of SiO with the diameter of 1 mu m₂Placing the microsphere solution in a centrifuge tube, and centrifuging;

(2) adding a proper amount of ethanol, and performing ultrasonic dispersion to obtain SiO₂An ethanol dispersion;

(3) dispersing the well dispersed SiO₂Spreading the ethanol dispersion on a glass slide, volatilizing ethanol, and placing in a plasma sputtering apparatusPerforming magnetron sputtering on SiO by using Au as target material₂Sputtering one side surface of the microsphere to form an Au layer, wherein the sputtering pressure is 2.0Pa, and the sputtering time is 3 min;

(4) after the sputtering is finished, taking out the glass slide, and carrying out ultrasonic treatment to obtain Au-SiO with a Janus structure₂A micro-nano motor.

The micro-nano motor has a structure shown in fig. 1, and includes a microsphere 110 and a photo-thermal material layer 120 sputtered on the surface of the microsphere 110, where the photo-thermal material layer 120 is an Au layer in this embodiment.

The embodiment also provides a micro-nano motor directional motion model, which comprises a liquid crystal box, wherein the liquid crystal box is composed of two conductive substrates and main body liquid crystal packaged between the two conductive substrates, and the two conductive substrates are used for applying voltage to the main body liquid crystal so as to change the orientation of the main body liquid crystal. The liquid crystal box also comprises at least one micro-nano motor, wherein the micro-nano motor is dispersed in the main liquid crystal and can generate self-thermophoresis under the stimulation of illumination.

The preparation process of the micro-nano motor directional motion model is as follows:

taking the Au-SiO prepared in the previous step₂The micro-nano motor is subjected to thiol modification to be better doped into a positive liquid crystal mixture, and Au-SiO is subjected to capillary action₂The micro-nano motor and the positive liquid crystal mixture are filled into liquid crystal boxes with the interval of 10 mu m.

The directional motion method of the micro-nano motor in the micro-nano motor directional motion model comprises the following steps:

the passing power is 2W cm^-2The near infrared light of the specific wave band irradiates Au-SiO in the liquid crystal box₂The micro-nano motor generates autophoretic movement, and in the movement process, when the micro-nano motor moves to a set position, alternating current with proper intensity is applied through the conductive substrates at the two sides to change the deflection of main body liquid crystal in a liquid crystal box and drive the Au-SiO₂And (3) controlling the precise directional motion of the micro-nano motor.

Example 2

The embodiment provides a micro-nano motor, and the preparation process of the micro-nano motor is as follows:

(1) taking a proper amount of SiO with the diameter of 3 mu m₂Placing the microsphere solution in a centrifuge tube, and centrifuging;

(2) adding a proper amount of ethanol, and performing ultrasonic dispersion to obtain SiO₂An ethanol dispersion;

(3) dispersing the well dispersed SiO₂Spreading the ethanol dispersion on a glass slide, volatilizing ethanol, and magnetron sputtering in a plasma sputtering apparatus to obtain Au target material on SiO₂Sputtering one side surface of the microsphere to form an Au layer, wherein the sputtering pressure is 2.0Pa, and the sputtering time is 5 min;

(4) after the sputtering is finished, taking out the glass slide, and carrying out ultrasonic treatment to obtain Au-SiO with a Janus structure₂A micro-nano motor.

The micro-nano motor has a structure shown in fig. 1, and includes a microsphere 110 and a photo-thermal material layer 120 sputtered on the surface of the microsphere 110, where the photo-thermal material layer 120 is an Au layer in this embodiment.

The embodiment also provides a micro-nano motor directional motion model, which comprises a liquid crystal box, wherein the liquid crystal box is composed of two conductive substrates and main body liquid crystal packaged between the two conductive substrates, and the two conductive substrates are used for applying voltage to the main body liquid crystal so as to change the orientation of the main body liquid crystal. The liquid crystal box also comprises at least one micro-nano motor, wherein the micro-nano motor is dispersed in the main liquid crystal and can generate self-thermophoresis under the stimulation of illumination.

The preparation process of the micro-nano motor directional motion model is as follows:

taking the Au-SiO prepared in the previous step₂The micro-nano motor is subjected to thiol modification to be better doped into a positive liquid crystal mixture, and Au-SiO is subjected to capillary action₂The micro-nano motor and the positive liquid crystal mixture are filled into liquid crystal boxes with the interval of 20 mu m.

The directional motion method of the micro-nano motor in the micro-nano motor directional motion model comprises the following steps:

the passing power is 2W cm^-2The near infrared light of the specific wave band irradiates Au-SiO in the liquid crystal box₂The micro-nano motor makes the micro-nano motor generate self-thermophoretic movement and move in the self-thermophoretic movementIn the process, when the liquid crystal display moves to a set position, alternating current with proper intensity is applied to the conductive substrates on the two sides to change the deflection of main body liquid crystal in the liquid crystal box and drive the Au-SiO₂And (3) controlling the precise directional motion of the micro-nano motor.

Example 3

The embodiment provides a micro-nano motor, and the preparation process of the micro-nano motor is as follows:

(1) taking a proper amount of SiO with the diameter of 5 mu m₂Placing the microsphere solution in a centrifuge tube, and centrifuging;

(2) adding a proper amount of ethanol, and performing ultrasonic dispersion to obtain SiO₂An ethanol dispersion;

(3) dispersing the well dispersed SiO₂Spreading the ethanol dispersion on a glass slide, volatilizing ethanol, and magnetron sputtering in a plasma sputtering apparatus to obtain Au target material on SiO₂Sputtering one side surface of the microsphere to form an Au layer, wherein the sputtering pressure is 2.0Pa, and the sputtering time is 7 min;

(4) after the sputtering is finished, taking out the glass slide, and carrying out ultrasonic treatment to obtain Au-SiO with a Janus structure₂A micro-nano motor.

The micro-nano motor has a structure shown in fig. 1, and includes a microsphere 110 and a photo-thermal material layer 120 sputtered on the surface of the microsphere 110, where the photo-thermal material layer 120 is an Au layer in this embodiment.

The embodiment also provides a micro-nano motor directional motion model, which comprises a liquid crystal box, wherein the liquid crystal box is composed of two conductive substrates and main body liquid crystal packaged between the two conductive substrates, and the two conductive substrates are used for applying voltage to the main body liquid crystal so as to change the orientation of the main body liquid crystal. The liquid crystal box also comprises at least one micro-nano motor, wherein the micro-nano motor is dispersed in the main liquid crystal and can generate self-thermophoresis under the stimulation of illumination.

The preparation process of the micro-nano motor directional motion model is as follows:

taking the Au-SiO prepared in the previous step₂The micro-nano motor is subjected to thiol modification to be better doped into a positive liquid crystal mixture, and Au-SiO is subjected to capillary action₂Micro-nano motor andboth positive liquid-crystal mixtures were filled into liquid-crystal cells with a spacing of 10 μm.

The directional motion method of the micro-nano motor in the micro-nano motor directional motion model comprises the following steps:

the passing power is 2W cm^-2The near infrared light of the specific wave band irradiates Au-SiO in the liquid crystal box₂The micro-nano motor generates autophoretic movement, and in the movement process, when the micro-nano motor moves to a set position, alternating current with proper intensity is applied through the conductive substrates at the two sides to change the deflection of main body liquid crystal in a liquid crystal box and drive the Au-SiO₂And (3) controlling the precise directional motion of the micro-nano motor.

Example 4

The present embodiment provides a directional movement method of a micro-nano motor, which is different from embodiment 1 in that a photo-thermal material layer of the micro-nano motor used in the qualitative movement method is platinum. The micro-nano motor can also be used for performing accurate qualitative motion control.

The present application has been described in detail with reference to the embodiments, but the present application is not limited to the embodiments described above, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present application. Furthermore, the embodiments and features of the embodiments of the present application may be combined with each other without conflict.