CN111960379A - A kind of preparation method of biomimetic controllable adsorption - Google Patents

Abstract

A preparation method for biomimetic controllable adsorption belongs to the technical field of biomimetic microstructure manufacturing in micro-nano engineering. The specific scheme includes the following steps: step 1: preparation of a metal master mold; step 2: silanization of the master mold; step 3: Assembling the sleeve; Step 4: pouring the polymer; Step 5: Controlling the surface flatness of the polymer; Step 6: Constant temperature curing and peeling of bionic controllable adsorption. The process of the invention is simple, does not involve complex chemical reactions, is environmentally friendly and efficient, and the relevant process parameters are also controllable. The prepared main mold is durable and can be used repeatedly for many times. Adsorption characteristics: Based on this preparation method, the characteristic dimensions (such as vertical height, tip angle, and inclination angle) of the wedge-shaped microstructure can also be flexibly changed. The modification or optimization of these characteristic dimensions is beneficial for improving the adsorption performance of biomimetic controllable adsorption.

Description

A kind of preparation method of biomimetic controllable adsorption

technical field

The invention belongs to the technical field of bionic microstructure manufacturing in micro-nano engineering, and in particular relates to a continuous inclined wedge-shaped

Preparation method of biomimetic controllable adsorption of microstructure array.

Background technique

The controllable adsorption system of gecko feet is currently the most versatile and effective biological function adsorption system known in nature. Due to its unique adsorption characteristics, it has the ability to easily and quickly climb on various surfaces.

At present, many biomimetic functional adsorption based on microstructure have been developed, but in these existing studies, there are not many biomimetic functional adsorption that can effectively reproduce the controllable adsorption characteristics of gecko feet, and it is precisely the controllability of bionic functional adsorption. It is of great significance for its effective application in robot climbing, target grasping and other fields.

The inclined wedge-shaped microstructure has been shown to possess outstanding controllable adsorption properties due to its great similarity to gecko bristles, and its potential for space-oriented floating target capture due to its controllability has also been confirmed. Although a few processing techniques have been developed to fabricate wedge-shaped microstructure arrays, they all suffer from varying degrees of problems: bilateral and dual-angle lithography processes can only produce upright wedge-shaped microstructures, and they still require high-precision exposure. Alignment, the process is time-consuming, expensive, and the yield is relatively low; although the two-step oblique exposure process can produce inclined wedge-shaped microstructures, it is the same as the bilateral and dual-angle lithography processes. The preparation threshold is high, and the process is relatively complex. The corresponding cost is also high, and the forming molds created by the two do not have good durability; although the micromachining process based on traditional mechanical indentation makes up for the complex process and high cost of the lithography process, it still faces the problem of high cost. The problem that the forming mold does not have good durability; although the ultra-precision diamond fly-cutting method improves the durability of the forming mold to a certain extent, due to the inherent characteristics of the fly-cutting process, the actual wedge-shaped micro-cavity is along the mold surface. The circumference is radially distributed, so the wedge-shaped microstructure array prepared based on the mold can only be used in a small size, which greatly restricts the application potential of the wedge-shaped microstructure array. Accordingly, how to process arrays with wedge-shaped microstructures efficiently, with high quality, and in batches is still an urgent problem to be solved.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a preparation method of bionic controllable adsorption in order to solve the problems existing in the prior art.

The purpose of this invention is to realize through the following technical solutions:

A preparation method of bionic controllable adsorption, comprising the following steps:

Step 1: Using an ultra-precise multi-step layered scribing strategy to prepare a master mold with a continuous inclined wedge-shaped cavity array;

Step 2: silanizing the prepared master mold;

Step 3: Set a frame on the outer periphery of the main mold;

Step 4: pour the polymer that is uniformly stirred and degassed into the main mold after the frame is set and degassed again;

Step 5: Lay a layer of film on the polymer, then cover with a cover plate and add a balance load;

Step 6: After the polymer is cured at a constant temperature, it is peeled off from the main mold to obtain a biomimetic controllable adsorption with a continuous inclined wedge-shaped microstructure array.

Further, in step 1, the ultra-precise multi-step hierarchical scribing strategy includes the following steps:

Step 1: Clamp the mold blank and the V-shaped tool on the ultra-precision machine tool, and complete the tool setting;

Step 2: When the tool scribes the mold blank, the upper surface of the tool and the mold blank form a corresponding inclination angle according to the expected inclination angle of the wedge-shaped cavity, and the scribing direction is perpendicular to the V-shaped cross section of the tool;

Step 3: The tip of the V-shaped tool is scored layer by layer to form a continuous inclined wedge-shaped cavity;

Step 4: According to the design spacing of the wedge-shaped cavity, the mold blanks are sequentially advanced, so as to process the next wedge-shaped cavity, until the scribing of several wedge-shaped cavities is completed, and a master mold with several continuous inclined wedge-shaped cavity arrays is obtained; The progressive direction of the pieces is perpendicular to the scribing direction of the tool.

Further, in step 2, the inclination angle of the center symmetry plane of the tool relative to the upper surface of the mold blank is in the range of 22.5°-90°, and the angle of the tip of the tool is in the range of 15°-30°.

Further, in step 3, the tip angle of the tool is the same as the tip angle of the wedge-shaped cavity.

Further, in step 3, the vertical height of the wedge-shaped cavity is 50-150 μm.

Further, in step 1, the continuous inclined wedge-shaped cavity array includes a plurality of elongated wedge-shaped cavities arranged in parallel, and each of the wedge-shaped cavities is arranged obliquely.

Further, in step 1, the shape of the main mold is square.

Further, in step 4, the polymer is silicone rubber or polyurethane.

Further, in step 6, the biomimetic controllable adsorption includes a substrate and a continuous inclined wedge-shaped microstructure array disposed on the substrate, and the continuous inclined wedge-shaped microstructure array includes a plurality of juxtaposed elongated wedge-shaped microstructures, each The wedge-shaped microstructures are all arranged obliquely, and the wedge-shaped microstructures are consistent with the cavity shape of the wedge-shaped cavity.

Further, the height of the frame is the sum of the height of the main mold and the thickness of the bionic controllable adsorption substrate.

Compared with the prior art, the present invention has the following advantages:

Based on the proposed ultra-precise multi-step layered scribing strategy, the present invention prepares a metal master mold with a continuous inclined wedge-shaped microcavity array. The master mold can not only be reused many times, but also replicate several centimeters or even tens of centimeters. The continuous inclined wedge-shaped microstructure array of large and small size, the continuously inclined wedge-shaped microstructure array enables the bionic controllable adsorption to have obvious controllable adsorption, dynamic adsorption and other outstanding adsorption characteristics of gecko feet, and the controllable adsorption characteristics can help achieve non-destructive to the target surface. and undisturbed adsorption and grip; and the dynamic adsorption feature can help realize the dynamic adjustment of the adsorption state during the sliding process of the adsorption interface, thereby avoiding sudden adsorption failure. In addition, the whole process involved in the present invention is simple to operate, does not involve any complex chemical reaction, is environmentally friendly and efficient, and the relevant process parameters are also controllable, the prepared main mold is durable and can be reused many times, and the obtained bionic controllable adsorption has Obvious controllable adsorption and dynamic adsorption characteristics; based on this preparation method, the characteristic dimensions (such as vertical height, tip angle and inclination angle) of the wedge-shaped microstructure can also be flexibly changed. Adsorption properties are beneficial. The bionic controllable adsorption is expected to be applied to fields such as robot climbing, space target adsorption and grasping.

Description of drawings

Figure 1 is a schematic diagram of the adsorption principle of biomimetic controllable adsorption based on a continuous inclined wedge-shaped microstructure array; in which, A is the initial contact state between the biomimetic controllable adsorption and the interactive interface, and B is the close contact between the biomimetic controllable adsorption and the interactive interface state; where a is the positive load, and b is the tangential load; the bionic controllable adsorption mainly activates the adsorption function through the tangential load b under the auxiliary action of the positive load a;

Figure 2 shows the passive adsorption process of the bionic controllable adsorption captured by the video, including the initial contact state (c), the intermediate contact state (d) and the close contact state (e) between the bionic controllable adsorption and the interactive interface in Figure 1;

Figure 3 is a schematic diagram of the motion configuration of an ultra-precision machine tool;

Figure 4 is a schematic diagram of the ultra-precision multi-step layered scribing strategy; in the figure, C is the cutting direction of the tool, D is the retracting direction, E is the direction of the tool returning to the initial position, F is the feeding direction of the tool, and G is the cutting direction. The scribed area, H is the progressive direction of the mold blank;

Figure 5 is a schematic diagram of the feeding direction and the number of times of the cutting tool when a wedge-shaped cavity is cut. In the figure, 1 to n are the cutting times of the tool, I is the cutting mark corresponding to the cut section of each layer, and J is the feed of the cutting tool. give direction;

6 is a schematic structural diagram of a master mold having a continuous inclined wedge-shaped microcavity array;

7 is a scanning electron microscope image of a master mold with a continuous inclined wedge-shaped microcavity array;

Fig. 8 is a schematic diagram of the casting molding process of bionic controlled adsorption; (I) silanization of the surface of the main mold; (II) assembling the main mold, frame and glass bottom plate; (III) pouring polymer and laying a film; (IV) constant temperature Curing process, (V) exfoliation of the polymer; (VI) biomimetic controllable adsorption prepared.

Figure 9 is a scanning electron microscope image of biomimetic controllable adsorption with a continuous inclined wedge-shaped microstructure array;

Fig. 10 is a force space scatter plot reflecting the controllable adsorption characteristics of bionic controllable adsorption; K is the maximum positive adsorption = 4.048KPa, L is the maximum tangential friction = 64.39KPa.

Fig. 11 is the force-time curve reflecting the dynamic adsorption characteristics of bionic controllable adsorption; M is the dynamic friction area; N is the tangential friction; O is the preload; P is the horizontal drag; Q is the peeling; R is the dynamic adsorption area; S is positive adsorption;

In the figure, 1. Main mold, 2. Frame, 3. Film, 4. Cover plate, 5. Balanced load, 6. Bionic controllable adsorption, 7. Glass substrate, 8. Polymer, 11. Wedge-shaped cavity, 01, Mold blanks, 02, tools, 03, ultra-precision machine tools, 61, substrate, 62, wedge-shaped microstructure.

Detailed ways

The technical solution of the present invention will be further described below in conjunction with the accompanying drawings 1-11 and the specific embodiments, but is not limited to this, any modification or equivalent replacement of the technical solution of the present invention (such as adopting a smaller or larger tip angle) diamond cutters, changing the vertical height/inclined angle of the wedge-shaped microstructure, etc.) without departing from the scope of the technical solution of the present invention, should all be included in the protection scope of the present invention.

Specific implementation one

A preparation method of bionic controllable adsorption, comprising the following steps:

Step 1: Using an ultra-precise multi-step layered scribing strategy to prepare a master mold 1 with a continuous inclined wedge-shaped cavity array; the continuous inclined wedge-shaped cavity array The wedge-shaped cavities 11 are all inclined; the shape of the main mold 1 is square, and the preferred material is brass;

Step 2: place the prepared master mold 1 in an environment full of fluorosilane vapor for silanization treatment;

Step 3: a frame 2 made of metal is sleeved on the outer periphery of the main mold 1; preferably, the material of the frame 2 is aluminum alloy;

Step 4: The polymer 8 after being stirred evenly and degassed is poured into the main mold 1 after the frame 2 is set and degassed again; preferably, the polymer 8 is silicone rubber or polyurethane, but not only Limited to this, any polymer that does not react with the material of the main mold and does not strongly bond with the surface of the main mold is applicable to the present invention;

Step 5: Spread a layer of PET film 3 on the polymer 8, then cover with a smooth and flat cover plate 4 and add a balance load 5;

Step 6: After the polymer 8 is cured at a constant temperature, it is peeled off from the main mold 1 to obtain a bionic controllable adsorption 6 with a continuous inclined wedge-shaped microstructure array; The microstructure array, the continuous inclined wedge-shaped microstructure array includes a plurality of long wedge-shaped microstructures 62 arranged in parallel, each of the wedge-shaped microstructures 62 is arranged obliquely, the wedge-shaped microstructures 62 and the wedge-shaped cavity 11 The shape of the cavity is consistent; the height of the frame 2 is the sum of the height of the main mold 1 and the thickness of the substrate 61 of the bionic controllable adsorption 6 .

Further, in step 1, the ultra-precise multi-step hierarchical scribing strategy includes the following steps:

Step 1: Clamp the mold blank 01 and the V-shaped diamond tool 02 on the ultra-precision machine tool 03, and complete the tool setting;

Step 2: When the diamond tool 02 scribes the mold blank 01, the upper surface of the diamond tool 02 and the mold blank 01 are at a corresponding inclination angle according to the expected inclination angle of the wedge-shaped cavity 11, and the scribing direction is the same as the V of the diamond tool 02. The shape cross section is vertical; specifically along the Y-axis direction of the ultra-precision machine tool 03 coordinate system, the angle range between the center symmetry plane of the diamond tool 02 and the upper surface of the mold blank 01 is 22.5°-90°, preferably 45- 90°; the range of the tip angle of the diamond tool 02 is 15°-30°, preferably, the angle between the center symmetry plane of the diamond tool 02 and the upper surface of the die blank 01 is 60°, and the tip angle of the diamond tool 02 is 20°.

Step 3: The tip of the V-shaped diamond tool 02 is scribed and accumulated layer by layer to form a long continuous inclined wedge-shaped cavity 11; the tip angle of the diamond tool 02 is the same as the tip angle of the wedge-shaped cavity 11; the wedge-shaped cavity 11 The vertical height of the wedge-shaped cavity 11 is 50-150 μm, preferably, the vertical height of the wedge-shaped cavity 11 is 100 μm;

Step 4: According to the design spacing of the wedge-shaped cavities 11, the mold blanks 01 are successively advanced, and the next wedge-shaped cavity 11 is further processed until the scribing of several wedge-shaped cavities 11 is completed, and a master mold with several continuous inclined wedge-shaped cavity arrays is obtained. 1; wherein the progressive direction of the mold blanks 01 is perpendicular to the direction of the diamond tool 02 scribing, specifically along the X-axis direction of the ultra-precision machine tool 03 coordinate system.

Example 1

A preparation method for biomimetic controllable adsorption comprises the following two major steps:

In the first step, a metal master mold 1 with a continuous inclined wedge-shaped cavity array was fabricated based on an ultra-precise multi-step hierarchical scribing strategy. First, a square semi-finished part of the mold is obtained based on the milling process, that is, the mold blank 01. The length × width of the mold blank 01 is determined by the linear motion limit of the ultra-precision machine tool 03, the macro size of the required bionic controllable adsorption 6, and the sharp point The life of the V-shaped diamond tool 02 is determined by a common trade-off. Then, prepare an ultra-precision machine tool 03 (with at least three linear motion axes X, Y and Z as shown in FIG. 3 ), clamp the mold blank 01 and the diamond tool 02 according to the desired posture, and complete the tool setting. Finally, the ultra-precision multi-step layered scribing begins. As shown in Figure 4, during scribing, the V-shaped section of the diamond tool 02 is parallel to the section of the wedge-shaped cavity 11 to be formed, and the scribing direction is the same as the V-shaped section of the diamond tool 02. The cross section is vertical; a formed wedge-shaped cavity 11 is formed by scribing and accumulating layer by layer by the sharp-point V-shaped diamond tool 02. Only part of the cross-section of the diamond tool 02 is involved in the scribing, as shown in Figure 5; when the designed wedge-shaped cavity 11 depth is reached, that is, one wedge-shaped cavity 11 is processed, the mold blank 01 will gradually increase according to the design spacing of the wedge-shaped cavity 11. One more time, and then the next wedge-shaped cavity 11 is processed, and the progressive direction of the mold blank 01 is perpendicular to the scribing direction of the diamond tool 02 . In this cycle, the schematic diagram of the finally formed metal master mold 1 with a continuous inclined wedge-shaped cavity array is shown in FIG. 6 , and the front and top SEM images of the actually formed wedge-shaped cavity 11 are shown in FIG.

In the second step, biomimetic controllable adsorption with a continuous inclined wedge-shaped microstructure array was prepared based on the casting molding process, as shown in Figure 8. First, the prepared metal master mold 1 is subjected to silanization treatment in an environment filled with fluorosilane vapor, and the treatment time is 16-24 hours. Then, the metal frame 2 that controls the thickness of the bionic controllable adsorption substrate 61 is assembled with the metal master mold 1, and the glass substrate 7 is used to cover the back; then, the polymer 8 after uniform stirring and degassing is poured into the assembled metal master mold 1 and do degassing again, the degassing time is generally 10-15min. Next, lay the PET film 3 prepared in advance on the polymer 8 , and then cover with a smooth and flat glass cover plate 4 and add a balance load 5 . Next, the polymer 8 is cured by placing the entire assembly in an incubator. Finally, the cured polymer 8 is sequentially peeled off from the metal master mold 1 to obtain a biomimetic controllable adsorption 6 with a continuous inclined wedge-shaped microstructure array. FIG. 9 is a scanning electron microscope image of the biomimetic controllable adsorption, and FIGS. 10 and 11 respectively show the controllable adsorption characteristics and the dynamic adsorption characteristics of the biomimetic controllable adsorption involved in the present invention.

As shown in Figures 1 and 2, the adsorption principle of a biomimetic controllable adsorption based on a continuous inclined wedge-shaped microstructure array is as follows:

The adsorption process of biomimetic controllable adsorption 6 is essentially a passive adsorption process under the action of external positive and tangential loads: when no external load is applied, the continuous inclined wedge-shaped microstructure of biomimetic controllable adsorption 6 remains in a natural state, which is only in the natural state. Under the action of its own gravity, a point contact is formed between the interface to be interacted with, because there is not enough contact area to generate effective adsorption, and the bionic controllable adsorption 6 is in a non-adsorption state at this time; when positive and tangential external loads are applied, the bionic The continuous inclined wedge-shaped microstructure of the controllable adsorption 6 gradually bends in response to the external load, so as to finally form a close surface contact with the interface to be interacted, because the large contact area generates an effective adsorption force, at this time, the bionic controllable adsorption 6 in an effective adsorption state. From the initial point contact to the final surface contact, the deformation of the wedge-shaped microstructure gradually increases, and finally a close contact is formed to achieve strong adhesion; the greater the deformation of the wedge-shaped microstructure, the larger the formed interface interaction area, and the obtained The bonding ability is also stronger. In addition, within the range of the maximum positive adsorption force that can be achieved by the bionic controllable adsorption 6, its positive adsorption force can be regulated by the external tangential load (tangential force/tangential displacement), that is, the larger the external tangential load, the corresponding The positive adsorption force formed is also greater.

Claims (10)

1. A preparation method of bionic controllable adsorption is characterized by comprising the following steps:

the method comprises the following steps: preparing a main die (1) with a continuous inclined wedge-shaped cavity array by adopting an ultra-precise multi-step layered scribing strategy;

step two: performing silanization treatment on the prepared main die (1);

step three: a frame (2) is sleeved on the outer periphery of the main die (1);

step four: pouring the polymer which is uniformly stirred and degassed into the main mould (1) after the frame (2) is sleeved and degassing again;

step five: laying a layer of film (3) on the polymer, covering a cover plate (4) and adding a balance load (5);

step six: and (3) after the polymer is solidified at constant temperature, peeling the polymer from the main mold (1) to obtain the bionic controllable adsorption (6) with the continuous inclined wedge-shaped microstructure array.

2. The preparation method of biomimetic controllable adsorption according to claim 1, characterized in that: in the first step, the ultra-precise multi-step layered scribing strategy comprises the following steps:

step 1: clamping a die blank (01) and a V-shaped cutter (02) on an ultra-precision machine tool (03), and finishing tool setting;

step 2: when the cutter (02) scores the die blank (01), the cutter (02) and the upper surface of the die blank (01) are in corresponding inclination angles according to the expected inclination angle of the wedge-shaped cavity, and the scoring direction is vertical to the V-shaped cross section of the cutter (02);

and step 3: the tip of the V-shaped cutter (02) is scribed and accumulated layer by layer to form a continuously inclined wedge-shaped cavity (11);

and 4, step 4: according to the design interval of the wedge-shaped cavities (11), sequentially advancing the mould blank (01) so as to process the next wedge-shaped cavity (11) until the scribing of a plurality of wedge-shaped cavities (11) is completed, and obtaining a main mould (1) with a plurality of continuous inclined wedge-shaped cavity arrays; wherein the progressive direction of the die blanks (01) is vertical to the scribing direction of the cutter (02).

3. The preparation method of biomimetic controllable adsorption according to claim 1, characterized in that: in the first step, the continuous inclined wedge-shaped cavity array comprises a plurality of strip-shaped wedge-shaped cavities (11) which are arranged in parallel, and each wedge-shaped cavity (11) is arranged in an inclined manner.

4. The preparation method of biomimetic controllable adsorption according to claim 1, characterized in that: in the first step, the main die (1) is square.

5. The preparation method of biomimetic controllable adsorption according to claim 2, characterized in that: in the step 2, the inclination angle range of the central symmetry plane of the cutter (02) relative to the upper surface of the die blank (01) is 22.5-90 degrees, and the angle range of the tip of the cutter (02) is 15-30 degrees.

6. The preparation method of biomimetic controllable adsorption according to claim 2, characterized in that: in step 3, the tip angle of the cutter (02) is the same as the tip angle of the wedge-shaped cavity (11).

7. The preparation method of biomimetic controllable adsorption according to claim 2, characterized in that: in step 3, the vertical height of the wedge-shaped cavity (11) is 50-150 μm.

8. The preparation method of biomimetic controllable adsorption according to claim 1, characterized in that: in the fourth step, the polymer is silicon rubber or polyurethane.

9. The preparation method of biomimetic controllable adsorption according to claim 1, characterized in that: in the sixth step, the bionic controllable adsorption device (6) comprises a substrate (61) and a continuous inclined wedge-shaped microstructure array arranged on the substrate (61), the continuous inclined wedge-shaped microstructure array comprises a plurality of strip-shaped wedge-shaped microstructures (62) which are arranged in parallel, each wedge-shaped microstructure (62) is arranged in an inclined mode, and the shape of each wedge-shaped microstructure is consistent with that of a cavity of the wedge-shaped cavity (11).

10. The method for preparing biomimetic controllable adsorption according to claim 9, characterized in that: the height of the frame (2) is the sum of the height of the main die (1) and the thickness of the substrate (61) of the bionic controllable adsorption device (6).

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