阅读说明：本技术 基于微纳增材制备仿生黏附材料的方法 (Method for preparing bionic adhesion material based on micro-nano additive ) 是由 何青松 张昊 于敏 孙正 尹国校 潘辉 赵泽芳 戴振东 于 2020-12-10 设计创作，主要内容包括：本发明公开了一种基于微纳增材制备仿生黏附材料的方法,包括以下步骤：将增塑剂和有机溶剂混合,加入聚氯乙烯粉末,得到聚氯乙烯凝胶溶液；将微纳增材制造的微纳模具置于容器中,倒入聚氯乙烯凝胶溶液,抽真空去除聚氯乙烯凝胶溶液中的气泡；将容器放入在玻璃密封罐中,置于真空干燥箱中升温使有机溶剂挥发后取出,脱模获得微纳模具的聚氯乙烯凹模；将聚氯乙烯凹模置于容器中,倒入二次倒模材料,抽真空去除气泡；待二次倒模材料固化后,取出后分离聚氯乙烯凹模即获得仿生黏附材料。本发明通过两次倒模法所制备的仿生黏附材料具有较好的黏附性能、较高弹性模量、重复采用性,本发明公开了其制法,该方法适用于制备多种微纳结构的仿生黏附材料。(The invention discloses a method for preparing a bionic adhesion material based on micro-nano additive materials, which comprises the following steps: mixing a plasticizer and an organic solvent, and adding polyvinyl chloride powder to obtain a polyvinyl chloride gel solution; placing a micro-nano die manufactured by micro-nano additive manufacturing in a container, pouring a polyvinyl chloride gel solution, and vacuumizing to remove bubbles in the polyvinyl chloride gel solution; putting the container into a glass sealing tank, putting the container into a vacuum drying oven, heating to volatilize the organic solvent, taking out the container, and demolding to obtain a polyvinyl chloride female die of the micro-nano die; placing a polyvinyl chloride female die in a container, pouring a secondary die-pouring material, and vacuumizing to remove bubbles; and after the secondary die-casting material is solidified, taking out the secondary die-casting material, and separating the polyvinyl chloride female die to obtain the bionic adhesive material. The bionic adhesive material prepared by the two-time reverse mold method has good adhesive performance, high elastic modulus and reusability, and the preparation method is suitable for preparing the bionic adhesive materials with various micro-nano structures.)

1. A method for preparing a bionic adhesion material based on micro-nano additive materials is characterized by comprising the following steps: the method comprises the following steps:

step 1, mixing a plasticizer and an organic solvent, and stirring in a magnetic stirrer; then adding polyvinyl chloride powder into the mixed solution, and placing the mixed solution on a magnetic stirrer for stirring to obtain a polyvinyl chloride gel solution;

step 2, placing a micro-nano die for micro-nano additive manufacturing in a container, pouring the polyvinyl chloride gel solution obtained in the step 1, and vacuumizing to remove bubbles in the polyvinyl chloride gel solution; putting the container into a glass sealing tank, putting the container into a vacuum drying oven, heating to volatilize the organic solvent, taking out the container, and demolding to obtain a polyvinyl chloride female die of the micro-nano die;

step 3, placing the polyvinyl chloride female die obtained in the step 2 into a container, pouring a secondary die-casting material, and vacuumizing to remove bubbles; and after the secondary die-pouring material is solidified, taking out the secondary die-pouring material, and separating the polyvinyl chloride female die to obtain the bionic adhesion material with the same structure as the micro-nano die for additive manufacturing.

2. The method for preparing the biomimetic adhesive material based on the micro-nano additive material according to claim 1, characterized in that: in the step 1, the mass ratio of the polyvinyl chloride powder to the plasticizer is 1: 1-1: 5, the mass ratio of the polyvinyl chloride powder to the organic solvent is 1: 10-1: 20.

3. the method for preparing the biomimetic adhesive material based on the micro-nano additive material according to claim 1 or 2, characterized in that: the average molecular weight of the polyvinyl chloride powder is 10000-200000.

4. The method for preparing the biomimetic adhesive material based on the micro-nano additive material according to claim 1 or 2, characterized in that: the plasticizer is one of dibutyl adipate, dioctyl phthalate and tricresyl phosphate.

5. The method for preparing the biomimetic adhesive material based on the micro-nano additive material according to claim 1 or 2, characterized in that: the organic solvent is one of tetrahydrofuran, N-dimethylformamide and N-butyl acetate.

6. The method for preparing the biomimetic adhesive material based on the micro-nano additive material according to claim 1, characterized in that: in the step 1, the first magnetic stirring is carried out for 5 minutes at 500r/min, and the second magnetic stirring is carried out for 24 hours at 1500 r/min.

7. The method for preparing the biomimetic adhesive material based on the micro-nano additive material according to claim 1, characterized in that: in the step 2, the micro-nano mold is obtained through a micro-nano additive manufacturing technology, and the micro-nano additive manufacturing technology comprises surface projection micro-stereolithography forming, two-photon curing and photocuring; the micro-nano mold is made of hard resin.

8. The method for preparing the biomimetic adhesive material based on the micro-nano additive material according to claim 1, characterized in that: in the step 3, the secondary die-casting material is one of polydimethylsiloxane, epoxy resin and polyurethane.

Technical Field

The invention relates to a method for preparing a bionic adhesion material based on micro-nano additive materials, and belongs to the technical field of bionic adhesion materials.

Background

The gecko which is a representative animal with excellent crawling capability in nature can freely crawl on vertical wall surfaces and ceilings and even on smooth glass windows, and micro-nano hierarchical structure bristles densely distributed on the ventral surfaces of the toes of the gecko are in close contact with the surfaces by virtue of a terminal nano spoon-projection structure to generate weak van der Waals force and converge into macroscopic adhesion force, so that a gecko adhesion system has excellent performances of high-strength adhesion, easy desorption, repeatable adhesion and the like, and great attention is paid to scientists and engineering technicians in various fields. Domestic and foreignMuch work has been done and great progress has been made in the development of gecko-like adhesion arrays. Cutkosky et al, Stanford university, USA, developed a sharp-ended tilted millimeter-scale array from the viewpoint of optimizing the morphology of the adhesion strut. Prepared by a machining micro-die casting method, the casting material is Polyurethane (IE-20 AH Polyurethane, E is 0.3MPa), and the adhesion strength of an adhesion array obtained by a casting test is about 0.24N/cm²And has obvious anisotropy, can realize similar slip-stick phenomenon in the gecko crawling process, has been primarily applied to a gecko-simulated wall-climbing robot, and has achieved good effect (Santos D, Kim S, Spenko M, Parness A, Cutkosky M. direct adhesive structures for controlled compact on mechanical surfaces.2007IEEE International Conference on Robotics and Automation, Roma, Italy,10-14April 2007.). The German Binder Jan processes the gecko-like dry adhesion structure with the mushroom-shaped structure at the tail end of the strut by a rolling die to obtain a micro-adhesion array with the length of 100 mu m and the diameter of 35 mu m, and the maximum normal adhesion strength can reach 6N/cm²(Tuma Jan,Gottlieb Binder GMBH&Process for creating attachment on a substrate material european Patent, EP20040722156, WO 2005/087033a 1). The ultra-precise diamond processing mold is adopted in Qinghua university field sunshine to prepare the polydimethylsiloxane-based inclined dry adhesion array, and the adhesion strength can reach 1.05N/cm²(Tao D, Gao X, Lu H, Liu Z, Li Y, Tong H, Pesika N, Meng Y, and Tian Y. controllable immunological Dry addition in Vacuum: Gecko implanted Wedged Surface fabric with ultra prediction Diamond cutting. adv. Funct. Mater.2017,27,16065761-9.). Bionic Dry Adhesive Materials with Mushroom-head-Shaped strut ends were prepared by Photolithography template by Metin Sitti et al, university of Chimomen, and Shajin Yokou et al, university of Western Ann transportation (Wang Y, Hu H, Shao J Y, Ding Y.C. fabrication of Well-Defined Mushoom-Shaped Structures for biomedical Dry Adhesive by scientific Photocurable and Molding. ACS Applied Materials&Interfaces,2014,6, 2213-. Chinese courtyard complexPreparing a template by utilizing an ICP deep etching method, pouring polydimethylsiloxane, curing and demolding to obtain a micro-adhesion array with various length-diameter ratios, wherein the normal adhesion strength measured by an array with the length of 5 microns and the diameter of 2 microns is the largest and can reach 1.94N/cm²(Chengrong, Meitao, Nilin, et al. Gekko Swinhonis micro-nano adhesion array technology preparation MEMS devices and technologies, 2006,9, 434-. The strongly adhered-easily desorbed vertically aligned carbon nanotube array is prepared by Dai LM et al of Dayton university in America by using a low-pressure chemical vapor deposition method, and the tangential adhesion strength is close to 100N/cm²This is 10 times the adhesion strength of the gecko's sole bristles (Qu L, Dai L, Stone M, Xia Z, Wang Z. carbon nanotube arrays with strand shear binding-on and easy normal lifting-off. science,2008,322, 238-.

In summary, various research institutions have adopted different methods such as machining, photolithography, chemical vapor deposition and the like to develop the biomimetic adhesive material, and although the methods have achieved good effects, the preparation methods have the defects of high cost and time consumption.

Disclosure of Invention

The invention aims to provide a method for preparing a bionic adhesion material based on micro-nano additive materials, which aims to reduce the preparation cost of the bionic adhesion material, shorten the preparation period and simultaneously solve the adhesion phenomenon between the material and a mold when a micro-nano structure is demolded.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for preparing a bionic adhesion material based on micro-nano additive materials comprises the following steps:

step 1, mixing a plasticizer and an organic solvent, and stirring in a magnetic stirrer; then adding polyvinyl chloride powder into the mixed solution, and placing the mixed solution on a magnetic stirrer for stirring to obtain a polyvinyl chloride gel solution;

step 2, placing a micro-nano die for micro-nano additive manufacturing in a container, pouring the polyvinyl chloride gel solution obtained in the step 1, and vacuumizing to remove bubbles in the polyvinyl chloride gel solution; putting the container into a glass sealing tank, putting the container into a vacuum drying oven, heating to volatilize the organic solvent, taking out the container, and demolding to obtain a polyvinyl chloride female die of the micro-nano die;

step 3, placing the polyvinyl chloride female die obtained in the step 2 into a container, pouring a secondary die-casting material, and vacuumizing to remove bubbles; and after the secondary die-pouring material is solidified, taking out the secondary die-pouring material, and separating the polyvinyl chloride female die to obtain the bionic adhesion material with the same structure as the micro-nano die for additive manufacturing.

In the step 1, the mass ratio of the polyvinyl chloride powder to the plasticizer is 1: 1-1: 5, the mass ratio of the polyvinyl chloride powder to the organic solvent is 1: 10-1: 20.

the average molecular weight of the polyvinyl chloride powder is 10000-200000.

The plasticizer is one of dibutyl adipate (DBA), dioctyl phthalate (DOP) and tricresyl phosphate (TCP).

The organic solvent is one of Tetrahydrofuran (THF), N, N-Dimethylformamide (DMF) and N-Butyl Acetate (BAC).

In the step 1, the first magnetic stirring is carried out for 5 minutes at 500r/min, and the second magnetic stirring is carried out for 24 hours at 1500 r/min.

In the step 2, the micro-nano mold is obtained through a micro-nano additive manufacturing technology, and the micro-nano additive manufacturing technology comprises surface projection micro-stereolithography forming, two-photon curing and photocuring; the micro-nano mold is made of hard resin.

In the step 3, the secondary mold-reversing material is one of Polydimethylsiloxane (PDMS), epoxy resin (EP) and Polyurethane (PU).

Has the advantages that: according to the invention, the concave die with a corresponding structure is obtained by casting the micro-nano die manufactured by additive manufacturing by using the PVC gel solution, and the volume of the PVC gel solution is slightly reduced in the volatilization and solidification processes, so that the PVC gel is automatically separated from the die to realize the demoulding, and the difficulty in demoulding the micro-nano structure is obviously reduced; and the bionic adhesive material is obtained by pouring on the PVC female die by utilizing the excellent elasticity of the PVC gel. The method reduces the preparation cost of the bionic adhesion material and shortens the preparation period. And simultaneously, the adhesion phenomenon of the material and the die during the demoulding of the micro-nano structure is solved.

Drawings

FIGS. 1a and 1b are SEM images of a photocured printing microstructure mold used in example 1 of the present invention; wherein FIG. 1a is a surface; FIG. 1b is a side view;

FIG. 2 is a schematic view of a method for preparing a PVC female mold according to example 1 of the present invention;

FIGS. 3a and 3b are SEM images of PDMS-based biomimetic adhesive material prepared in example 1 of the present invention; wherein FIG. 3a is a surface; FIG. 3b is a side view;

FIGS. 4a and 4b are SEM images of the CNT-doped PDMS-based biomimetic adhesive material prepared in example 1 of the present invention; wherein FIG. 4a is a surface; FIG. 4b is a side view;

FIGS. 5a and 5b are SEM images of the epoxy-based biomimetic adhesive material prepared in example 1 of the present invention; wherein FIG. 5a is a surface; FIG. 5b is a side view;

FIG. 6 shows normal adhesion of three biomimetic adhesive materials prepared in examples 1, 2 and 3 under different loads.

Detailed Description

The invention discloses a method for preparing a bionic adhesion material based on micro-nano additive materials, which comprises the following steps:

step 1, mixing a plasticizer and an organic solvent, and stirring for 5 minutes at a speed of 500r/min on a magnetic stirrer; adding PVC powder into a conical flask, and stirring for 24 hours on a magnetic stirrer at 1500r/min to obtain a polyvinyl chloride gel solution;

wherein the mass ratio of the polyvinyl chloride powder to the plasticizer is 1: 1-1: 5, the mass ratio of the polyvinyl chloride powder to the organic solvent is 1: 10-1: 20;

wherein the average molecular weight of the polyvinyl chloride powder is 10000-200000; the plasticizer is one of dibutyl adipate (DBA), dioctyl phthalate (DOP) and tricresyl phosphate (TCP); the organic solvent is one of Tetrahydrofuran (THF), N, N-Dimethylformamide (DMF), and N-Butyl Acetate (BAC).

Step 2, placing a micro-nano die for micro-nano additive manufacturing in a container, pouring the polyvinyl chloride gel solution obtained in the step 1, and vacuumizing to remove bubbles in the polyvinyl chloride gel solution; putting the container into a glass sealing tank, putting the container into a vacuum drying oven, heating to volatilize the organic solvent, taking out the container, and demolding to obtain a polyvinyl chloride female die of the micro-nano die;

the micro-nano mold is obtained by adopting micro-nano additive manufacturing technologies such as surface projection micro-stereolithography, two-photon curing and photo-curing, and is made of hard resin.

Step 3, placing the polyvinyl chloride female die obtained in the step 2 into a container, pouring a secondary die-casting material, and vacuumizing to remove bubbles; after the secondary die-pouring material is solidified, taking out the secondary die-pouring material, and separating the polyvinyl chloride female die to obtain the bionic adhesion material with the same structure as the material increase manufacturing micro-nano die;

wherein, the secondary mold-reversing material is one of substrate materials such as Polydimethylsiloxane (PDMS), epoxy resin (EP), Polyurethane (PU) and the like.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples, and the equipment and reagents used in the examples and test examples are commercially available without specific reference. The specific embodiments described herein are merely illustrative of the invention and are not intended to be limiting.

The micro-nano bionic dry adhesion material array manufactured by additive casting in the following embodiment has a plane size of 14mm x 14mm, wherein the upper surface has a mushroom head micro-pillar structure shown in fig. 1, and the micro-pillar has a height of 70um and a diameter of 50 um; the mushroom head size is height 30um, diameter 80um, and the centerline distance between two microcolumns is 120 um.

Example 1

Preparation of polydimethylsiloxane based mushroom-shaped bionic adhesion material

Dibutyl adipate (DBA), Tetrahydrofuran (THF) were chosen as the plasticizer and organic solvent for this example, and other types of plasticizers and organic solvents had similar functions and effects.

Step 1, preparing a PVC gel solution:

according to the mass ratio of PVC powder, plasticizer (DBA) and organic solvent (THF) of 1: 1.75: 15, adding the mixture into a conical flask, placing the conical flask on a magnetic stirrer, stirring the mixture for 5 minutes at 500r/min, adding PVC into the conical flask, placing the conical flask on the magnetic stirrer, and stirring the mixture for 24 hours at 1500r/min to obtain a PVC gel solution;

step 2, primary die reversing:

placing the additive manufacturing micro-nano mold in a glass culture dish, pouring the mold by adopting a PVC solution, placing the solution in a vacuum box after natural leveling, removing bubbles by vacuumizing, and fully permeating the PVC gel solution into the mold; and (3) putting the beaker into a glass sealing tank, and putting the beaker into a forced air drying oven to be subjected to forced air drying at 60 ℃ for 24 hours to obtain the PVC female die corresponding to the micro-nano additive manufacturing die, wherein the preparation flow is shown in figure 2.

Step 3, carrying out secondary die reversing on the PVC female die:

according to the weight ratio of A, B, component 10: preparing Dow Corning 184 polydimethylsiloxane according to the mass ratio of 1, and uniformly stirring; placing the PVC female die in a beaker, pouring the prepared polydimethylsiloxane, and vacuumizing to remove bubbles; and (3) placing the beaker in a blast drying oven, keeping the temperature at 80 ℃ for 1 hour, taking out the beaker, and separating the PVC female die to obtain the polydimethylsiloxane-based bionic adhesive material with the same structure as the material increase manufacturing.

Compared with the mold, the prepared polydimethylsiloxane-based bionic adhesion material has the advantages that the size of the micro-support of the mushroom head micro-support structure is 47um in height and 40um in diameter; the mushroom head size is height 20um, and the diameter is 60um, and the centerline distance between two microcolumns is 90 um. The lateral dimension is reduced by about 20% and the longitudinal dimension is reduced by about 30%, as shown in fig. 3.

Example 2

Preparation of carbon nano tube doped polydimethylsiloxane based bionic adhesion material

Dibutyl adipate (DBA), Tetrahydrofuran (THF) were chosen as the plasticizer and organic solvent for this example, and other types of plasticizers and organic solvents had similar functions and effects.

Step 1, preparing a PVC gel solution:

according to the mass ratio of PVC powder, plasticizer (DBA) and organic solvent (THF) of 1: 1.75: 15, adding the mixture into a conical flask, placing the conical flask on a magnetic stirrer, stirring the mixture for 5 minutes at 500r/min, adding PVC into the conical flask, placing the conical flask on the magnetic stirrer, and stirring the mixture for 24 hours at 1500r/min to obtain a PVC gel solution;

step 2, primary die reversing:

placing the additive manufacturing micro-nano mold in a glass culture dish, pouring the mold by adopting a PVC solution, placing the solution in a vacuum box after natural leveling, removing bubbles by vacuumizing, and fully permeating the PVC gel solution into the mold; and (3) putting the beaker into a glass sealing tank, and putting the beaker into a blast drying oven to carry out blast drying at 60 ℃ for 24 hours to obtain the PVC female die corresponding to the micro-nano additive manufacturing die.

Step 3, carrying out secondary die reversing on the PVC female die:

the adhesion material for imitating the gecko adhesion array and the preparation thereof are prepared by using the carbon nanotube doped polydimethylsiloxane disclosed in the Chinese patent document 'Daizong, Zengsong, hypersensitive, Zhang Hao';

according to the A component of the Dow Corning 184, the B component of the Dow Corning 184 and the B component of the Dow Corning 186, the mass ratio of the carbon nano tubes is 10: 0.5: 0.5: 0.05 preparing carbon nano tube doped polydimethylsiloxane, and uniformly stirring; placing the PVC female die in a beaker, pouring the prepared carbon nanotube doped polydimethylsiloxane, and vacuumizing to remove bubbles; placing the beaker in a blast drying oven, keeping the temperature at 80 ℃ for 1 hour, taking out the beaker, separating the PVC female die to obtain the carbon nanotube doped polydimethylsiloxane bionic adhesive material with the same structure as additive manufacturing, wherein the size of the micro-pillar of the mushroom head micro-pillar structure is 47um in height and 40um in diameter; the mushroom head size is height 20um, and the diameter is 60um, and the centerline distance between two microcolumns is 90 um. The lateral dimension is reduced by about 20% and the longitudinal dimension is reduced by about 30%, as shown in fig. 4.

Example 3

Preparing an epoxy resin-based bionic adhesion material:

step 1, preparing a PVC gel solution:

according to the mass ratio of PVC powder, plasticizer (DBA) and organic solvent (THF) of 1: 1.75: 15, adding the mixture into a conical flask, placing the conical flask on a magnetic stirrer, stirring the mixture for 5 minutes at 500r/min, adding PVC into the conical flask, placing the conical flask on the magnetic stirrer, and stirring the mixture for 24 hours at 1500r/min to obtain a PVC gel solution;

step 2, primary die reversing:

dibutyl adipate (DBA), Tetrahydrofuran (THF) were chosen as the plasticizer and organic solvent for this example, and other classes of plasticizers and organic solvents have similar functions and effects.

Placing the additive manufacturing micro-nano mold in a glass culture dish, pouring the mold by adopting a PVC solution, placing the solution in a vacuum box after natural leveling, removing bubbles by vacuumizing, and fully permeating the PVC gel solution into the mold; and (3) putting the beaker into a glass sealing tank, and putting the beaker into a blast drying oven to carry out blast drying at 60 ℃ for 24 hours to obtain the PVC female die corresponding to the micro-nano additive manufacturing die.

Step 3, carrying out secondary die reversing on the PVC female die:

epoxy resin (EP) was chosen as the material for the second pour of this example;

according to the weight ratio of A, B, component 3: 1, pouring the solution by using the epoxy resin solution, and uniformly stirring; placing the PVC female die in a beaker, pouring the prepared epoxy resin solution, and vacuumizing to remove bubbles; keeping the beaker in a room temperature environment for 24 hours, taking out the beaker, separating the PVC female die to obtain the epoxy resin-based bionic adhesive material with the same structure as additive manufacturing, wherein the size of the micro-support of the mushroom head micro-support structure is 47um in height and 30um in diameter; the mushroom head size is height 20um, diameter 46um, and the centerline distance between two microcolumns is 90 um. The lateral dimension is reduced by about 40% and the longitudinal dimension is reduced by about 30%, as shown in fig. 5.

FIG. 6 shows normal adhesion forces of three biomimetic adhesive materials prepared in examples 1, 2 and 3 under different loads; the adhesion force can be improved to a certain extent by preparing the array structure, and the adhesion force is related to the preparation process, the size of the microarray, the structure and the like; meanwhile, compared with the three exemplary materials, the adhesion force of the carbon nanotube doped polydimethylsiloxane with the high surface energy and the epoxy resin can be enhanced.

The present invention can be better understood from the above examples. However, it is easily understood by those skilled in the art that the specific material specifications (additive manufacturing method, micro-nano mold material and structure, PVC gel component, base material type and model, etc.), process conditions and results thereof described in the examples are only for illustrating the present invention and should not limit the present invention detailed in the claims.