CN117186576A - Hydrogel with controllable response lubricating property and preparation method and application thereof - Google Patents

Abstract

The invention provides a hydrogel with controllable response lubricating performance, which is mucin-polyvinyl alcohol hydrogel, mucin-polyvinyl alcohol/sodium alginate hydrogel, mucin-polyvinyl alcohol/sodium carboxymethyl cellulose hydrogel, mucin-acrylamide hydrogel or mucin-hydroxyethyl methacrylate hydrogel, and is obtained through preparation of mucin aqueous solution, hydrogel precursor liquid and molding treatment. The hydrogel with controllable response lubricating property provided by the invention has a low friction coefficient, and can be applied to the preparation of soft robots.

Description

A hydrogel with controllable response lubrication properties and its preparation method and application

Technical field

The invention belongs to the technical field of hydrogels, and specifically relates to a hydrogel with controllable response lubrication properties and its preparation method and application.

Background technique

When an object and another object move along the tangent direction of the contact surface or have a tendency to move relative to each other, there is a force between the contact surfaces of the two objects that hinders their relative movement. This force is called friction force, and the contact surface between This phenomenon or characteristic is called "friction". The energy lost due to friction in the world accounts for about 23% of global energy consumption every year. Therefore, reducing the harm caused by friction is of great practical significance. Lubrication is required to reduce friction. Lubrication is an effective technical measure to improve the friction state of the friction pair to reduce frictional resistance and slow down wear.

Hydrogel is a gel with water as the dispersion medium. It is a polymer network system that is soft in nature and can maintain a certain shape. It is widely used in many fields, such as: drought resistance in arid areas and in cosmetics. However, due to poor friction and wear properties, the practical application of hydrogels in various scenarios is limited. How to prepare hydrogels with lubricating properties is currently needed.

Contents of the invention

The problem to be solved by the present invention is: a hydrogel with controllable response lubrication performance and its preparation method and application, so as to solve the problems of poor lubrication performance and narrow application range of hydrogel.

The technical solution adopted to solve the technical problem is to provide a hydrogel with controllable response lubrication properties. The hydrogel is mucin-polyvinyl alcohol hydrogel, mucin-polyvinyl alcohol/sodium alginate. Hydrogel, mucin-polyvinyl alcohol/sodium carboxymethylcellulose hydrogel, mucin-acrylamide hydrogel, or mucin-hydroxyethyl methacrylate hydrogel.

The invention also provides a method for preparing a hydrogel with controllable response lubrication properties, which includes the following steps:

(1) Dissolve mucin in water, then centrifuge, and take the supernatant to obtain a mucin aqueous solution;

(2) Prepare the base liquid; the base liquid is polyvinyl alcohol aqueous solution, a mixed solution of polyvinyl alcohol and sodium alginate, a mixed solution of polyvinyl alcohol and sodium carboxymethylcellulose, acrylamide-mucin aqueous solution or hydroxyethyl methacrylate Ester-mucin aqueous solution;

(3) Prepare a hydrogel precursor liquid; the hydrogel precursor liquid is obtained by mixing a base liquid containing polyvinyl alcohol and a mucin aqueous solution, or by adding an initiator and a cross-linking agent to a base liquid that does not contain polyvinyl alcohol. ;

(4) Perform molding treatment on the hydrogel precursor liquid to obtain.

Preferably, the concentration of the mucin aqueous solution is 30-90 mg/mL, the centrifugation speed is 12000 r/min, and the centrifugation time is 20 min.

Preferably, the hydrogel is mucin-polyvinyl alcohol hydrogel, which is prepared through the following steps:

(1) Mix polyvinyl alcohol with a molecular weight of 100,000 to 150,000 and a degree of alcoholysis of 99% with water and stir it at 98°C for 3 hours to obtain a polyvinyl alcohol aqueous solution; the concentration of the polyvinyl alcohol aqueous solution is 10 to 20wt%;

(2) Mix the polyvinyl alcohol aqueous solution and the mucin aqueous solution at a volume ratio of 1:1 to obtain a hydrogel precursor liquid;

(3) Freeze the hydrogel precursor liquid at -40°C for 8 hours, then defrost it at 25 to 30°C for 8 hours, and freeze and thaw 1 to 3 times to obtain it.

Preferably, the hydrogel is mucin-polyvinyl alcohol/sodium alginate hydrogel, which is prepared through the following steps:

(1) Mix polyvinyl alcohol with a molecular weight of 100,000 to 150,000 and an alcoholysis degree of 99% with water and stir at 98°C for 2 hours. Then add sodium alginate and mix evenly to obtain a mixed solution of polyvinyl alcohol and sodium alginate. ; The concentration of the mixed solution of polyvinyl alcohol and sodium alginate is 10-25wt%; the mass ratio of polyvinyl alcohol and sodium alginate is 25:4;

(2) Mix the mixed solution of polyvinyl alcohol and sodium alginate with the mucin aqueous solution at a volume ratio of 1:1 to obtain a hydrogel precursor liquid;

(3) Freeze the hydrogel precursor liquid at -40°C for 8 hours, then defrost it at 25 to 30°C for 8 hours, and freeze and thaw 1 to 3 times to obtain it.

Preferably, the hydrogel is mucin-polyvinyl alcohol/carboxymethylcellulose sodium hydrogel, which is prepared through the following steps:

(1) Mix polyvinyl alcohol with a molecular weight of 100,000 to 150,000 and a degree of alcoholysis of 99% with water and stir at 98°C for 3 hours. Then add sodium carboxymethylcellulose and mix evenly to obtain polyvinyl alcohol and carboxymethyl cellulose. A mixed solution of cellulose sodium; the concentration of the mixed solution of polyvinyl alcohol and sodium carboxymethylcellulose is 10 to 25 wt%; the mass ratio of polyvinyl alcohol to sodium carboxymethylcellulose is 25:4;

(2) Mix the mixed solution of polyvinyl alcohol and carboxymethyl cellulose sodium with the mucin aqueous solution at a volume ratio of 1:1 to obtain a hydrogel precursor liquid;

(3) Freeze the hydrogel precursor liquid at -40°C for 8 hours, then defrost it at 25 to 30°C for 8 hours, and freeze and thaw 1 to 3 times to obtain it.

Preferably, the hydrogel is a mucin-acrylamide hydrogel, which is prepared through the following steps:

(1) Dissolve acrylamide in an aqueous mucin solution to obtain an acrylamide-mucin aqueous solution; the concentration of the acrylamide-mucin aqueous solution is 15 to 20 wt%; the mass ratio of acrylamide to mucin is 25:3 to 9;

(2) Add cross-linking agent and initiator to the acrylamide-mucin aqueous solution in sequence, stir and dissolve to obtain a hydrogel precursor liquid; the added amounts of initiator and cross-linking agent are both 1% of the mass of acrylamide;

(3) Place the hydrogel precursor liquid at 50°C for 6 hours to obtain it.

Preferably, the hydrogel is mucin-hydroxyethyl methacrylate hydrogel, which is prepared through the following steps:

(1) Dissolve hydroxyethyl methacrylate in an aqueous mucin solution to obtain a hydroxyethyl methacrylate-mucin aqueous solution; the concentration of the hydroxyethyl methacrylate-mucin aqueous solution is 30 to 45 wt%; hydroxyethyl methacrylate-mucin aqueous solution The mass ratio of ethyl ester to mucin is 667:30~90;

(2) Add cross-linking agent and initiator to the hydroxyethyl methacrylate-mucin aqueous solution in sequence, stir and dissolve, and obtain a hydrogel precursor liquid; the added amounts of initiator and cross-linking agent are both hydroxyethyl methacrylate 1% of mass;

(3) React the hydrogel precursor liquid at 25-30°C for 6 hours to obtain.

Preferably, the cross-linking agent is N,N-methylenebisacrylamide and the initiator is ammonium persulfate.

The invention also provides an application of a hydrogel with controllable response lubrication properties in the preparation of soft robots.

The invention has the following beneficial effects:

(1) The hydrogel with controllable response lubrication properties prepared by the present invention can effectively reduce the friction coefficient, has excellent lubrication properties, and can achieve friction regulation under the action of tannic acid;

(2) The hydrogel prepared by the present invention is non-toxic and harmless, has good biocompatibility, and is suitable for multi-functional and multi-scenario applications;

(3) Hydrogel raw materials are cheap and easy to obtain, and the synthesis steps are simple, making it suitable for industrial production.

Description of the drawings

Figure 1 shows mucin-polyvinyl alcohol/sodium alginate hydrogel, mucin-polyvinyl alcohol/sodium carboxymethyl cellulose hydrogel, polyvinyl alcohol/sodium alginate hydrogel and polyvinyl alcohol/carboxymethyl cellulose hydrogel. Comparison chart of coefficient of friction (COF) of sodium methylcellulose hydrogel;

Figure 2 is a comparison chart of the coefficient of friction (COF) of mucin-acrylamide hydrogel, mucin-hydroxyethyl methacrylate hydrogel, acrylamide hydrogel and hydroxyethyl methacrylate hydrogel;

Figure 3 is a comparison chart of the coefficient of friction (COF) of mucin-polyvinyl alcohol hydrogels treated with tannic acid aqueous solutions of different concentrations.

Detailed ways

The features and performance of the present invention will be described in further detail below with reference to examples.

Example 1

A hydrogel with controllable response lubricating properties. The hydrogel is a mucin-polyvinyl alcohol hydrogel.

The mucin-polyvinyl alcohol hydrogel in this example is prepared through the following steps:

(1) Weigh 0.3g of mucin and add it to 10mL of deionized water, and use magnetic stirring to completely dissolve it. Then pour the solution into a centrifuge tube, put it into a centrifuge and centrifuge at 12000r/min. After 20 minutes, take the supernatant to obtain a mucin aqueous solution with a concentration of 30 mg/mL;

(2) Mix 2.5g of polyvinyl alcohol (PVA) with a molecular weight of 100,000 to 150,000 and a degree of alcoholysis of 99% with 10 mL of deionized water, then heat to 98°C and magnetically stir for 3 hours to obtain polyethylene with a concentration of 20wt% alcohol aqueous solution;

(3) Take 5 mL of polyvinyl alcohol aqueous solution and place it in a beaker, stir and add 5 mL of mucin aqueous solution, and mix evenly to obtain a hydrogel precursor liquid;

(4) Place the hydrogel precursor liquid into a template with D = 35 mm and H = 2.4 mm, and then freeze it in a -40°C refrigerator for 8 hours, then take it out and thaw it at 28° C for 8 hours, and repeat the freeze-thaw cycle After 3 times, mucin-polyvinyl alcohol hydrogel was obtained.

Example 2

A hydrogel with controllable response lubricating properties. The hydrogel is a mucin-polyvinyl alcohol hydrogel.

The mucin-polyvinyl alcohol hydrogel in this example is prepared through the following steps:

(1) Weigh 0.6g of mucin and add it to 10mL of deionized water, and use magnetic stirring to dissolve it completely. Then pour the solution into a centrifuge tube, put it into a centrifuge and centrifuge at 12000r/min for 20 minutes. From the supernatant, a mucin aqueous solution with a concentration of 60 mg/mL was obtained;

(2) Mix 2.5g of polyvinyl alcohol with a molecular weight of 100,000 to 150,000 and a degree of alcoholysis of 99% with 10 mL of deionized water, then heat to 98°C and magnetically stir for 3 hours to obtain a polyvinyl alcohol aqueous solution with a concentration of 20wt%;

(3) Take 5 mL of polyvinyl alcohol aqueous solution and place it in a beaker, stir and add 5 mL of mucin aqueous solution, and mix evenly to obtain a hydrogel precursor liquid;

(4) Place the hydrogel precursor liquid into a template with D=35mm and H=2.4mm, and then freeze it in a -40°C refrigerator for 8 hours, then take it out and defrost it at 25°C for 8 hours. This freeze-thaw cycle After 3 times, mucin-polyvinyl alcohol hydrogel was obtained.

Example 3

A hydrogel with controllable response lubricating properties. The hydrogel is a mucin-polyvinyl alcohol hydrogel.

The mucin-polyvinyl alcohol hydrogel in this example is prepared through the following steps:

(1) Weigh 0.9g of mucin and add it to 10mL of deionized water, and use magnetic stirring to dissolve it completely. Then pour the solution into a centrifuge tube, put it into a centrifuge and centrifuge at 12000r/min for 20 minutes. From the supernatant, a mucin aqueous solution with a concentration of 90 mg/mL was obtained;

(2) Mix 2.5g of polyvinyl alcohol with a molecular weight of 100,000 to 150,000 and a degree of alcoholysis of 99% with 10 mL of deionized water, then heat to 98°C and magnetically stir for 3 hours to obtain a polyvinyl alcohol aqueous solution with a concentration of 20wt%;

(3) Take 5 mL of polyvinyl alcohol aqueous solution and place it in a beaker, stir and add 5 mL of mucin aqueous solution, and mix evenly to obtain a hydrogel precursor liquid;

(4) Place the hydrogel precursor liquid into a template with D = 35 mm and H = 2.4 mm, and then freeze it in a -40°C refrigerator for 8 hours, then take it out and defrost it at 30°C for 8 hours, and repeat the freeze-thaw cycle After 3 times, mucin-polyvinyl alcohol hydrogel was obtained.

Example 4

A hydrogel with controllable response lubricating properties. The hydrogel is a mucin-polyvinyl alcohol hydrogel.

The mucin-polyvinyl alcohol hydrogel in this example is prepared through the following steps:

(1) Weigh 0.3g of mucin and add it to 10mL of deionized water, and use magnetic stirring to dissolve it completely. Then pour the solution into a centrifuge tube, place it in a centrifuge and centrifuge at 12000r/min for 20 minutes. From the supernatant, a mucin aqueous solution with a concentration of 30 mg/mL was obtained;

(2) Mix 2.5g of polyvinyl alcohol with a molecular weight of 100,000 to 150,000 and a degree of alcoholysis of 99% with 10 mL of deionized water, then heat to 98°C and magnetically stir for 3 hours to obtain a polyvinyl alcohol aqueous solution with a concentration of 20wt%;

(3) Take 5 mL of polyvinyl alcohol aqueous solution and place it in a beaker, stir and add 5 mL of mucin aqueous solution, and mix evenly to obtain a hydrogel precursor liquid;

(4) Place the hydrogel precursor liquid into a template with D = 35 mm and H = 2.4 mm, and then freeze it in a -40°C refrigerator for 8 hours, then take it out and defrost it at 30°C for 8 hours, and repeat the freeze-thaw cycle Once, mucin-polyvinyl alcohol hydrogel is obtained.

Example 5

A hydrogel with controllable response lubricating properties. The hydrogel is a mucin-polyvinyl alcohol hydrogel.

The mucin-polyvinyl alcohol hydrogel in this example is prepared through the following steps:

(1) Weigh 0.3g of mucin and add it to 10mL of deionized water, and use magnetic stirring to dissolve it completely. Then pour the solution into a centrifuge tube, place it in a centrifuge and centrifuge at 12000r/min for 20 minutes. From the supernatant, a mucin aqueous solution with a concentration of 30 mg/mL was obtained;

(2) Mix 2.5g of polyvinyl alcohol with a molecular weight of 100,000 to 150,000 and a degree of alcoholysis of 99% with 10 mL of deionized water, then heat to 98°C and magnetically stir for 3 hours to obtain a polyvinyl alcohol aqueous solution with a concentration of 20wt%;

(3) Take 5 mL of polyvinyl alcohol aqueous solution and place it in a beaker, stir and add 5 mL of mucin aqueous solution, and mix evenly to obtain a hydrogel precursor liquid;

(4) Place the hydrogel precursor liquid into a template with D = 35 mm and H = 2.4 mm, and then freeze it in a -40°C refrigerator for 8 hours, then take it out and defrost it at 30°C for 8 hours, and repeat the freeze-thaw cycle After 2 times, mucin-polyvinyl alcohol hydrogel was obtained.

Example 6

A hydrogel with controllable response lubricating properties. The hydrogel is a mucin-polyvinyl alcohol hydrogel.

The mucin-polyvinyl alcohol hydrogel in this example is prepared through the following steps:

(1) Weigh 0.6g of mucin and dissolve it in 10mL of deionized water, and use magnetic stirring to completely dissolve it. Then pour the solution into a centrifuge tube, put it into a centrifuge and centrifuge at 12000r/min for 20min. Take the supernatant to obtain a mucin aqueous solution with a concentration of 60 mg/mL;

(2) Mix 2.5g of polyvinyl alcohol with a molecular weight of 100,000 to 150,000 and a degree of alcoholysis of 99% with 10 mL of deionized water, then heat to 98°C and magnetically stir for 3 hours to obtain a polyvinyl alcohol aqueous solution with a concentration of 20wt%;

(3) Take 5 mL of polyvinyl alcohol aqueous solution and place it in a beaker, stir and add 5 mL of mucin aqueous solution, and mix evenly to obtain a hydrogel precursor liquid;

(4) Place the hydrogel precursor liquid into a template with D = 35 mm and H = 2.4 mm, and then freeze it in a -40°C refrigerator for 8 hours, then take it out and defrost it at 30°C for 8 hours, and repeat the freeze-thaw cycle Once, mucin-polyvinyl alcohol hydrogel is obtained.

Example 7

A hydrogel with controllable response lubricating properties. The hydrogel is a mucin-polyvinyl alcohol hydrogel.

The mucin-polyvinyl alcohol hydrogel in this example is prepared through the following steps:

(1) Weigh 0.6g of mucin and add it to 10mL of deionized water, and use magnetic stirring to dissolve it completely. Then pour the solution into a centrifuge tube, put it into a centrifuge and centrifuge at 12000r/min for 20 minutes. From the supernatant, a mucin aqueous solution with a concentration of 60 mg/mL was obtained;

(2) Mix 2.5g of polyvinyl alcohol with a molecular weight of 100,000 to 150,000 and a degree of alcoholysis of 99% with 10 mL of deionized water, then heat to 98°C and magnetically stir for 3 hours to obtain a polyvinyl alcohol aqueous solution with a concentration of 20wt%;

(3) Take 5 mL of polyvinyl alcohol aqueous solution and place it in a beaker, stir and add 5 mL of mucin aqueous solution, and mix evenly to obtain a hydrogel precursor liquid;

(4) Place the hydrogel precursor liquid into a template with D = 35 mm and H = 2.4 mm, and then freeze it in a -40°C refrigerator for 8 hours, then take it out and defrost it at 30°C for 8 hours, and repeat the freeze-thaw cycle After 2 times, mucin-polyvinyl alcohol hydrogel was obtained.

Example 8

A hydrogel with controllable response lubricating properties. The hydrogel is a mucin-polyvinyl alcohol hydrogel.

The mucin-polyvinyl alcohol hydrogel in this example is prepared through the following steps:

(1) Weigh 0.6g of mucin and add it to 10mL of deionized water, and use magnetic stirring to dissolve it completely. Then pour the solution into a centrifuge tube, put it into a centrifuge and centrifuge at 12000r/min for 20 minutes. From the supernatant, a mucin aqueous solution with a concentration of 60 mg/mL was obtained;

(2) Mix 2.5g of polyvinyl alcohol with a molecular weight of 100,000 to 150,000 and a degree of alcoholysis of 99% with 10 mL of deionized water, then heat to 98°C and magnetically stir for 3 hours to obtain a polyvinyl alcohol aqueous solution with a concentration of 20wt%;

(3) Take 5 mL of polyvinyl alcohol aqueous solution and place it in a beaker, stir and add 5 mL of mucin aqueous solution, and mix evenly to obtain a hydrogel precursor liquid;

(4) Place the hydrogel precursor liquid into a template with D = 35 mm and H = 2.4 mm, and then freeze it in a -40°C refrigerator for 8 hours, then take it out and defrost it at 30°C for 8 hours, and repeat the freeze-thaw cycle Once, mucin-polyvinyl alcohol hydrogel is obtained.

Example 9

A hydrogel with controllable response lubricating properties. The hydrogel is a mucin-polyvinyl alcohol hydrogel.

The mucin-polyvinyl alcohol hydrogel in this example is prepared through the following steps:

(1) Weigh 0.9g of mucin and add it to 10mL of deionized water, and use magnetic stirring to dissolve it completely. Then pour the solution into a centrifuge tube, place it in a centrifuge and centrifuge at 12000r/min for 20 minutes. From the supernatant, a mucin aqueous solution with a concentration of 90 mg/mL was obtained;

(2) Mix 2.5g of polyvinyl alcohol with a molecular weight of 100,000 to 150,000 and a degree of alcoholysis of 99% with 10 mL of deionized water, then heat to 98°C and magnetically stir for 3 hours to obtain a polyvinyl alcohol aqueous solution with a concentration of 20wt%;

(3) Take 5 mL of polyvinyl alcohol aqueous solution and place it in a beaker, stir and add 5 mL of mucin aqueous solution, and mix evenly to obtain a hydrogel precursor liquid;

(4) Place the hydrogel precursor liquid into a template with D = 35 mm and H = 2.4 mm, and then freeze it in a -40°C refrigerator for 8 hours, then take it out and defrost it at 30°C for 8 hours, and repeat the freeze-thaw cycle After 2 times, mucin-polyvinyl alcohol hydrogel was obtained.

Example 10

A hydrogel with controllable response lubricating properties. The hydrogel is mucin-polyvinyl alcohol/sodium alginate hydrogel.

The mucin-polyvinyl alcohol/sodium alginate hydrogel in this example is prepared through the following steps:

(1) Weigh 0.9g of mucin and add it to 10mL of deionized water, and use magnetic stirring to dissolve it completely. Then pour the solution into a centrifuge tube, place it in a centrifuge and centrifuge at 12000r/min for 20 minutes. From the supernatant, a mucin aqueous solution with a concentration of 90 mg/mL was obtained;

(2) Mix 2.5g of polyvinyl alcohol with a molecular weight of 100,000 to 150,000 and a degree of alcoholysis of 99% with 10 mL of deionized water, heat to 98°C and magnetically stir for 2 hours, then add 0.4g of sodium alginate (SA) , stir to mix evenly to obtain a mixed solution of polyvinyl alcohol and sodium alginate with a concentration of 22.48wt%;

(3) Take 5 mL of the mixed solution of polyvinyl alcohol and sodium alginate and place it in a beaker, stir and add 5 mL of the mucin aqueous solution, so that the mixed solution of polyvinyl alcohol and sodium alginate and the mucin aqueous solution are evenly mixed to obtain the hydrogel. body fluid;

(4) Place the hydrogel precursor liquid into the D=35mm, H=2.4mm template, then freeze it in a -40°C refrigerator for 8 hours, and then thaw it at 30°C for 8 hours. Repeat this freeze-thaw cycle three times. Mucin-polyvinyl alcohol/sodium alginate hydrogel is obtained.

Example 11

A hydrogel with controllable response lubricating properties. The hydrogel is mucin-polyvinyl alcohol/sodium carboxymethylcellulose hydrogel.

The mucin-polyvinyl alcohol/carboxymethylcellulose sodium hydrogel in this example is prepared through the following steps:

(1) Weigh 0.9g of mucin and add it to 10mL of deionized water, and use magnetic stirring to dissolve it completely. Then pour the solution into a centrifuge tube, place it in a centrifuge and centrifuge at 12000r/min for 20 minutes. From the supernatant, a mucin aqueous solution with a concentration of 90 mg/mL was obtained;

(2) Mix 2.5g of polyvinyl alcohol with a molecular weight of 100,000 to 150,000 and a degree of alcoholysis of 99% with 10 mL of deionized water, heat to 98°C and magnetically stir for 3 hours, and then add 0.4 g of sodium carboxymethylcellulose. (CMC), stir to mix evenly to obtain a mixed solution of polyvinyl alcohol and sodium carboxymethylcellulose with a concentration of 22.48wt%;

(3) Take 5 mL of the mixed solution of polyvinyl alcohol and sodium carboxymethyl cellulose and place it in a beaker. Stir and add 5 mL of the mucin aqueous solution until the mixed solution of polyvinyl alcohol and sodium carboxymethyl cellulose and the mucin aqueous solution are evenly mixed. , to obtain the hydrogel precursor liquid;

(4) Place the hydrogel precursor liquid into the D=35mm, H=2.4mm template, then freeze it in a -40°C refrigerator for 8 hours, and then thaw it at 30°C for 8 hours. Repeat this freeze-thaw cycle three times. The mucin-polyvinyl alcohol/carboxymethyl cellulose sodium hydrogel is obtained.

Example 12

A hydrogel with controllable response lubrication properties. The hydrogel is a mucin-acrylamide hydrogel hydrogel.

The mucin-acrylamide hydrogel in this example is prepared through the following steps:

(1) Weigh 0.9g of mucin and add it to 10mL of deionized water, and use magnetic stirring to dissolve it completely. Then pour the solution into a centrifuge tube, place it in a centrifuge and centrifuge at 12000r/min for 20 minutes. From the supernatant, a mucin aqueous solution with a concentration of 90 mg/mL was obtained;

(2) Dissolve 2.5g of acrylamide (AM) in 10 mL of mucin aqueous solution, and use magnetic stirring to completely dissolve it to obtain an acrylamide-mucin aqueous solution with a concentration of 20wt%;

(3) Take 5 mL of acrylamide-mucin aqueous solution and place it in a beaker, add 0.025g of N,N-methylenebisacrylamide, and then add 0.025g of ammonium persulfate, and magnetically stir to completely dissolve it to obtain water. Gel precursor fluid;

(4) Place the hydrogel precursor liquid into a D=35mm, H=2.4mm template, and then place it in an oven at 50°C for 6 hours to obtain mucin-acrylamide hydrogel.

Example 13

A hydrogel with controllable response lubricating properties. The hydrogel is a mucin-hydroxyethyl methacrylate hydrogel.

The mucin-hydroxyethyl methacrylate hydrogel in this example is prepared through the following steps:

(1) Weigh 0.9g of mucin and add it to 10mL of deionized water, and use magnetic stirring to dissolve it completely. Then pour the solution into a centrifuge tube, put it into a centrifuge and centrifuge at 12000r/min for 20 minutes. From the supernatant, a mucin aqueous solution with a concentration of 90 mg/mL was obtained;

(2) Dissolve 6.67g of hydroxyethyl methacrylate (HEMA) in 10 mL of mucin aqueous solution, and use magnetic stirring to completely dissolve it to obtain a hydroxyethyl methacrylate-mucin aqueous solution with a concentration of 40wt% ;

(3) Take 5mL of hydroxyethyl methacrylate-mucin aqueous solution and place it in a beaker. Add 0.025g of N,N-methylenebisacrylamide, then add 0.025g of ammonium persulfate, and stir magnetically to make it complete. Dissolve to obtain hydrogel precursor liquid;

(4) Place the gel precursor liquid into a D=35mm, H=2.4mm template, and then react at 30°C for 6 hours to obtain mucin-hydroxyethyl methacrylate hydrogel.

Comparative example 1

A hydrogel is a polyvinyl alcohol hydrogel.

The difference between the preparation process of polyvinyl alcohol hydrogel in this example and Example 3 is that step (2) is cancelled, and the mucin aqueous solution in step (4) is replaced with an equal amount of deionized water. The remaining steps are the same as those in Example 3. 3 are the same.

Comparative example 2

A hydrogel, which is polyvinyl alcohol/sodium alginate hydrogel.

The difference between the preparation process of polyvinyl alcohol/sodium alginate hydrogel in this example and Example 10 is that step (2) is cancelled, and the mucin aqueous solution in step (4) is replaced with an equal amount of deionized water. The steps are the same as in Example 10.

Comparative example 3

A hydrogel, the hydrogel is polyvinyl alcohol/sodium carboxymethylcellulose hydrogel.

The difference between the preparation process of polyvinyl alcohol/sodium carboxymethylcellulose hydrogel in this example and Example 11 is that step (2) is cancelled, and the mucin aqueous solution in step (4) is replaced with an equal amount of deionized water. water, and the remaining steps are the same as in Example 11.

Comparative example 4

A kind of hydrogel, the hydrogel is acrylamide hydrogel hydrogel.

The difference between the preparation process of acrylamide hydrogel in this example and Example 12 is that step (2) is cancelled, the mucin aqueous solution in step (3) is replaced with an equal amount of deionized water, and the remaining steps are the same as those in Example 12. same.

Comparative example 5

A hydrogel, the hydrogel is hydroxyethyl methacrylate hydrogel.

The difference between the preparation process of hydroxyethyl methacrylate hydrogel in this example and Example 13 is that step (2) is cancelled, the mucin aqueous solution in step (3) is replaced with an equal amount of deionized water, and the remaining steps Same as Example 13.

Experimental example

1. Friction coefficient test of hydrogel

Friction tests were performed on a conventional ball-disk reciprocating tribometer (tribometer UMT-2, CETR, Bruker, USA). Under a load of 1N, the stainless steel contact ball (diameter 6mm) performs reciprocating linear motion on the hydrogel surface at a shear speed of 0.5mm/s. A reciprocating linear motion is labeled as a shear cycle with a sliding distance of 5mm. The friction coefficients of the hydrogels prepared in Examples 1-13 and Comparative Examples 1-5 are shown in Table 1, Figure 1 and Figure 2.

Table 1

project Friction coefficient project Friction coefficient project Friction coefficient Example 1 0.022 Example 7 0.018 Example 13 0.026 Example 2 0.01 Example 8 0.02 Comparative example 1 0.18 Example 3 0.008 Example 9 0.012 Comparative example 2 0.09 Example 4 0.053 Example 10 0.021 Comparative example 3 0.082 Example 5 0.036 Example 11 0.018 Comparative example 4 0.32 Example 6 0.034 Example 12 0.031 Comparative example 5 0.56

As shown in Figure 1 and Table 1, by comparing the COF values of the hydrogels with responsive lubricating properties prepared in Examples 10 and 11 and Comparative Examples 2 and 3, it can be seen that mucin-polyvinyl alcohol/sodium alginate water The COF value of the gel is lower than that of polyvinyl alcohol/sodium alginate hydrogel. Similarly, the COF value of mucin-polyvinyl alcohol/sodium carboxymethylcellulose hydrogel is lower than that of polyvinyl alcohol. / The COF value of sodium carboxymethyl cellulose hydrogel is lower. The results show that mucin has a good lubricating effect and has a wide range of applications.

As shown in Figure 2 and Table 1, by comparing the COF values of the hydrogels with responsive lubrication properties prepared in Examples 12 and 13 and Comparative Examples 4 and 5, it can be seen that the COF value of the mucin-acrylamide hydrogel The COF value of mucin-hydroxyethyl methacrylate hydrogel is lower than that of acrylamide hydrogel. Similarly, the COF value of mucin-hydroxyethyl methacrylate hydrogel is lower than that of hydroxyethyl methacrylate hydrogel. The results show that Mucin has excellent lubricating effect and has a wide range of applications.

2. Friction coefficient test after treating mucin-polyvinyl alcohol hydrogel with tannic acid solution

Weigh 1g of tannic acid (TA) and dissolve it in 9 mL of deionized water, and use magnetic stirring to completely dissolve it to obtain a tannic acid aqueous solution with a concentration of 10wt%; then weigh 1.5g of tannic acid (TA) and dissolve it in 8.5 mL of deionized water, and use magnetic stirring to completely dissolve it to obtain a tannic acid aqueous solution with a concentration of 15wt%; then weigh 2g of tannic acid (TA) and dissolve it in 8 mL of deionized water, and use magnetic stirring to completely dissolve it. , to obtain a tannic acid aqueous solution with a concentration of 20wt%.

After treating the mucin-polyvinyl alcohol hydrogel with tannic acid aqueous solutions at concentrations of 10wt%, 15wt% and 20wt% for 1 minute, the mucin-polyvinyl alcohol hydrogel treated with the above three different concentrations of tannic acid aqueous solutions was detected. The friction coefficients of the gel and untreated mucin-polyvinyl alcohol hydrogel were tested, and the results are shown in Figure 3.

It can be seen from Figure 3 that the friction coefficient of the hydrogel treated with tannic acid will show an increasing trend, and the higher the tannic acid concentration, the higher the friction coefficient increases. This is due to the fact that mucin and tannic acid The interaction between polyphenol groups can cause mucin to agglomerate and precipitate, thus achieving friction regulation.

The present invention has been described based on the above-mentioned embodiments. It should be understood that the above-mentioned embodiments do not limit the present invention in any form. All technical solutions obtained by using equivalent substitutions or equivalent transformations fall within the scope of the present invention.

Claims (10)

1. A hydrogel having controlled responsive lubricating properties, characterized by: the hydrogel is mucin-polyvinyl alcohol hydrogel, mucin-polyvinyl alcohol/sodium alginate hydrogel, mucin-polyvinyl alcohol/sodium carboxymethyl cellulose hydrogel, mucin-acrylamide hydrogel or mucin-hydroxyethyl methacrylate hydrogel.

2. A method of preparing a hydrogel having controlled responsive lubricating properties as claimed in claim 1, comprising the steps of:

(1) Dissolving mucin in water, centrifuging, and collecting supernatant to obtain mucin water solution;

(2) Preparing a base solution; the base solution is a polyvinyl alcohol aqueous solution, a mixed solution of polyvinyl alcohol and sodium alginate, a mixed solution of polyvinyl alcohol and sodium carboxymethyl cellulose, an acrylamide-mucin aqueous solution or a hydroxyethyl methacrylate-mucin aqueous solution;

(3) Preparing hydrogel precursor liquid; the hydrogel precursor liquid is obtained by mixing a base liquid containing polyvinyl alcohol with a mucin aqueous solution, or is obtained by adding an initiator and a cross-linking agent into a base liquid without the polyvinyl alcohol;

(4) And (3) performing molding treatment on the hydrogel precursor liquid to obtain the hydrogel.

3. The method of manufacturing as claimed in claim 2, wherein: the concentration of the mucin aqueous solution is 30-90 mg/mL, the centrifugal speed is 12000r/min, and the centrifugal time is 20min.

4. The method of claim 3, wherein the hydrogel is a mucin-polyvinyl alcohol hydrogel, prepared by the steps of:

(1) Mixing polyvinyl alcohol with molecular weight of 100000 ～ 150000 and alcoholysis degree of 99% with water, and stirring for 3h at 98 ℃ to obtain a polyvinyl alcohol aqueous solution; the concentration of the polyvinyl alcohol aqueous solution is 10-20wt%;

(2) Mixing a polyvinyl alcohol aqueous solution and a mucin aqueous solution according to a volume ratio of 1:1 to obtain hydrogel precursor liquid;

(3) Freezing the hydrogel precursor liquid at-40 ℃ for 8 hours, thawing at 25-30 ℃ for 8 hours, and performing freeze thawing cycle for 1-3 times to obtain the gel.

5. The method of claim 3, wherein the hydrogel is a mucin-polyvinyl alcohol/sodium alginate hydrogel, and is prepared by the steps of:

(1) Mixing polyvinyl alcohol with molecular weight of 100000 ～ 150000 and alcoholysis degree of 99% with water, stirring at 98 ℃ for 2h, adding sodium alginate, and mixing uniformly to obtain a mixed solution of polyvinyl alcohol and sodium alginate; the concentration of the mixed solution of polyvinyl alcohol and sodium alginate is 10-25wt%; the mass ratio of the polyvinyl alcohol to the sodium alginate is 25:4;

(2) Mixing the mixed solution of polyvinyl alcohol and sodium alginate with mucin water solution according to the volume ratio of 1:1 to obtain hydrogel precursor liquid;

(3) Freezing the hydrogel precursor liquid at-40 ℃ for 8 hours, thawing at 25-30 ℃ for 8 hours, and performing freeze thawing cycle for 1-3 times to obtain the gel.

6. The method of claim 3, wherein the hydrogel is a mucin-polyvinyl alcohol/sodium carboxymethyl cellulose hydrogel, and is prepared by the steps of:

(1) Mixing polyvinyl alcohol with molecular weight of 100000 ～ 150000 and alcoholysis degree of 99% with water, stirring for 3h at 98 ℃, adding sodium carboxymethylcellulose, and mixing uniformly to obtain a mixed solution of polyvinyl alcohol and sodium carboxymethylcellulose; the concentration of the mixed solution of polyvinyl alcohol and sodium carboxymethyl cellulose is 10-25 wt%; the mass ratio of the polyvinyl alcohol to the sodium carboxymethyl cellulose is 25:4;

(2) Mixing a mixed solution of polyvinyl alcohol and sodium carboxymethyl cellulose with a mucin aqueous solution according to a volume ratio of 1:1 to obtain hydrogel precursor liquid;

(3) Freezing the hydrogel precursor liquid at-40 ℃ for 8 hours, thawing at 25-30 ℃ for 8 hours, and performing freeze thawing cycle for 1-3 times to obtain the gel.

7. A method of preparation according to claim 3, wherein the hydrogel is a mucin-acrylamide hydrogel prepared by the steps of:

(1) Dissolving acrylamide in a mucin aqueous solution to obtain an acrylamide-mucin aqueous solution; the concentration of the acrylamide-mucin aqueous solution is 15-20wt%; the mass ratio of the acrylamide to the mucin is 25:3-9;

(2) Sequentially adding a cross-linking agent and an initiator into the acrylamide-mucin aqueous solution, stirring and dissolving to obtain hydrogel precursor liquid; the addition amount of the initiator and the cross-linking agent is 1% of the mass of the acrylamide;

(3) Placing the hydrogel precursor liquid at 50 ℃ for 6 hours to obtain the hydrogel.

8. A method of preparation according to claim 3, wherein the hydrogel is a mucin-hydroxyethyl methacrylate hydrogel, prepared by the steps of:

(1) Dissolving hydroxyethyl methacrylate in a mucin aqueous solution to obtain a hydroxyethyl methacrylate-mucin aqueous solution; the concentration of the hydroxyethyl methacrylate-mucin aqueous solution is 30-45 wt%; the mass ratio of the hydroxyethyl methacrylate to the mucin is 667:30-90;

(2) Sequentially adding a cross-linking agent and an initiator into the hydroxyethyl methacrylate-mucin aqueous solution, and stirring and dissolving to obtain hydrogel precursor liquid; the addition amount of the initiator and the cross-linking agent is 1% of the mass of the hydroxyethyl methacrylate;

(3) The hydrogel precursor liquid is reacted for 6 hours at the temperature of 25-30 ℃ to obtain the hydrogel.

9. The production method according to any one of claims 7 to 8, wherein: the cross-linking agent is N, N-methylene bisacrylamide, and the initiator is ammonium persulfate.

10. Use of the hydrogel of claim 1 in the preparation of a soft robot.