CN115353661B - Hard magnetic porous material and preparation method and application thereof - Google Patents
Hard magnetic porous material and preparation method and application thereof Download PDFInfo
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Abstract
The invention belongs to the technical field of porous materials, and discloses a hard magnetic porous material, a preparation method and application thereof, wherein the method comprises the following steps: (1) Adding neodymium iron boron powder into the solution A of the silicon rubber, and uniformly dispersing to obtain a first mixture; (2) Adding the solution B of the silicon rubber and the diluent into the first mixture, and uniformly mixing to obtain a second mixture; (3) Pouring the second mixture into a mold, and placing a sugar template into the mold; (4) Placing the mold in a vacuum environment such that the second mixture completely fills the pores of the sugar template; (5) Taking out the die from the vacuum environment, standing at a preset temperature, and then heating to cure the silicone rubber; (6) And taking the sugar template out of the die, dissolving and removing the sugar template, and magnetizing to obtain the hard magnetic porous material. The invention has the advantages of simple and easily obtained materials, convenient operation mode, flexible movement realization and larger deformation under a magnetic field.
Description
Technical Field
The invention belongs to the technical field of porous materials, and particularly relates to a hard magnetic porous material, a preparation method and application thereof.
Background
Along with the development of scientific technology, the medical health field is receiving more and more attention, wherein the drug administration technology is particularly important because the drug administration technology affects the absorption, distribution, treatment effect, duration and side effect of the drug, the traditional drug administration technology mainly enters the human body through an oral or intravenous injection method and then moves to a target organ or a target cell to play a role through blood circulation, and in the process, the effective utilization rate of the drug is often less than 20%, so that how to realize accurate drug administration has great significance for the treatment of patients.
Magnetically controlled robots are considered as an effective way to achieve accurate in vivo dosing as a novel, cableless, remotely controllable therapeutic approach. At present, magnetic control robots for in-vivo drug delivery mainly can be divided into two types, one type is a centimeter-scale robot consisting of a magnet and a complex mechanical structure, and the magnetic control robots have the problems of large volume, poor biocompatibility, small carrying dosage, overlarge magnetic field for controlling the movement of the robots (possibly causing harm to human bodies) and the like; the other type is a millimeter-scale robot made of an elastomer doped with magnetic particles, and the soft magnetic robot has the problems of lack of sensing function, large control magnetic field, easy leakage of medicines and the like.
Therefore, a reliable technical means for realizing accurate administration is still lacking at present. Based on the existing problems of the magnetic robots, in order to solve the problems of large control magnetic field, compatibility, reliability and the like, the soft magnetic elastomer with a porous structure is considered to be a reliable method, the strength of an externally applied control magnetic field is reduced due to the lower Young modulus, and in addition, the porous material is widely applied to the field of medical health, has good biocompatibility and is also an excellent carrier of medicines.
However, most of the current magnetically porous materials are made of a mixture of soft magnetic materials and silicone rubber materials. The soft magnetic material has the characteristics of low coercive force and high magnetic permeability, can easily eliminate the original magnetic field under the action of an external magnetic field, and can generate obvious expansion and contraction phenomenon under the action of the magnetic field. Therefore, the soft magnetic material is not suitable for manufacturing soft robots with flexible movement function, and the soft magnetic porous material is contracted once being subjected to the action of an external magnetic field, so that the soft magnetic robots can have serious medicine leakage phenomenon in the movement process.
Disclosure of Invention
Aiming at the defects or improvement demands of the prior art, the invention provides a hard magnetic porous material, a preparation method and application thereof, wherein the hard magnetic porous material which can be used for drug delivery is prepared by using a simple and easily available material and an operation mode, not only can realize flexible movement in a small magnetic field (< 100 Gs), but also can generate larger deformation in the magnetic field, can be used for manufacturing a capacitive sensor, and is very suitable for accurate drug delivery.
In order to achieve the above object, according to one aspect of the present invention, there is provided a method for preparing a hard magnetic porous material, the method mainly comprising the steps of:
(1) Adding neodymium iron boron powder into the solution A of the silicon rubber, and uniformly dispersing to obtain a first mixture;
(2) Adding the solution B of the silicon rubber and the diluent into the first mixture, and uniformly mixing to obtain a second mixture;
(3) Pouring the second mixture into a mold, and placing a sugar template into the mold;
(4) Placing the mold in a vacuum environment such that the second mixture completely fills the pores of the sugar template;
(5) Taking out the die from the vacuum environment, standing at a preset temperature, and then heating to cure the silicone rubber;
(6) And taking the sugar template out of the die, dissolving and removing the sugar template, and magnetizing to obtain the hard magnetic porous material.
Further, the neodymium iron boron powder has a diameter of 5 microns.
Further, in the second mixture, the mass percentage content of each reactant is as follows: 30-60% of neodymium iron boron powder, 0-12% of diluent and 37-66% of silicon rubber material.
Further, the silicone rubber is Ecoflex-0030, and the diluent is Ecoflex-0030 or simethicone.
Further, the mold is 3D printed polylactic acid, and the sugar template is a cube sugar.
Further, the vacuum environment is: placing under vacuum degree of-0.05 mPa for thirty minutes; in a vacuum environment, the gas in the pores of the sugar template is sucked out to form a negative pressure, and the liquid mixture fills all the pores of the sugar template under the dual action of the negative pressure and capillary force and wets the whole sugar template.
Further, the method comprises the following steps of: placing the die in an environment at 4 ℃ for 10-12 hours; the mold was placed in an environment of 75±5 ℃ for 2 to 3 hours to cure the silicone rubber.
Further, the sugar template was placed in a container containing water, and heated and stirred with a magnetic stirrer at 80℃for 1 hour to dissolve the sugar template.
The invention also provides a hard magnetic porous material which is prepared by adopting the preparation method of the hard magnetic porous material.
The invention also provides application of the hard magnetic porous material in a flexible pressure capacitance type sensor, a magnetic field direction detection module and a drug delivery magnetic control soft robot.
In general, compared with the prior art, the hard magnetic porous material and the preparation method and application thereof have the following advantages:
1. according to the invention, after the neodymium iron boron powder and the solution A of the silicone rubber are uniformly mixed, the solution B of the silicone rubber and the diluent are added to be uniformly mixed, then the cube sugar block (sugar template) is soaked in the obtained mixture, the liquid mixture is soaked and fills all pores of the cube sugar block in a vacuumizing mode, the silicone rubber is solidified, finally the cube sugar block is washed out by hot water, so that the hard magnetic porous material with interconnected internal pores and uniformly distributed neodymium iron boron powder can be obtained.
2. In order to reduce the control magnetic field intensity of the hard magnetic porous material as much as possible, the silicone rubber material is selected from Ecoflex-0030 with low Young's modulus, however, once the A, B solution of Ecoflex-0030 is mixed, crosslinking and solidification can occur at normal temperature, and the hard to thoroughly infiltrate into the pores of the square sugar block, so that the iron boron powder can be uniformly distributed in the prepared porous material, and the reasons include: (1) Uniformly dispersing neodymium iron boron powder into the solution A of the silicon rubber material, and then adding the solution B; (2) In order to slow down the crosslinking curing rate of the silicone rubber material and also to further reduce the Young's modulus of the hard magnetic porous material, a diluent is added while the solution B is added; (3) After the cube sugar is soaked in the mixture, the cube sugar is quickly placed in a vacuum environment, and the liquid mixture is quickly filled in all pores of the cube sugar by utilizing capillary force; (4) After the square sugar blocks are taken out of the vacuum environment, the square sugar blocks are placed into low temperature for storage, the liquid mixture can slowly infiltrate the square sugar blocks, meanwhile, the silicon rubber material is continuously solidified, and the neodymium iron boron powder is fixed in the silicon rubber frame to form uniform distribution.
3. The curing rate of the second mixture and the Young's modulus of the formed hard magnetic porous material can be adjusted by adjusting the addition amount of the diluent and the NdFeB powder; further, the increase of the content of the NdFeB powder is beneficial to increasing the Young modulus, increasing the viscosity of the second mixture and being unfavorable for the second mixture to infiltrate and fill the pores of the square candy; the increased diluent content helps to reduce young's modulus, reduce the viscosity of the second mixture, slow the rate of solidification of the second mixture, and facilitate infiltration of the second mixture to fill the pores of the cube.
4. Compared with the soft magnetic porous material, the prepared hard magnetic porous material can generate obvious shrinkage phenomenon only in a specific magnetic field direction, and can not generate obvious shrinkage phenomenon in other magnetic fields, so that the problem of medicine leakage caused by shrinkage of the magnetic robot in the motion process is solved; in addition, the hard magnetic porous material provided by the invention can generate larger bending deformation under a smaller magnetic field, so that the flexible control on the movement of the magnetic robot can be realized only by a small control magnetic field (< 100 Gs), which is helpful for solving the problems of large control magnetic field and damage to human body and surrounding environment of the existing magnetic robot.
5. The hard magnetic porous material prepared by the preparation method can be used for preparing flexible pressure capacitance sensors and hard magnetic soft robots for drug delivery, the neodymium iron boron powder improves the dielectric constant change of the silicon rubber material in the compression process, and meanwhile, the porous structure reduces the Young modulus of the silicon rubber material and improves the sensitivity of the flexible sensors; the drug delivery soft robot made of the hard magnetic porous material can be driven by a smaller magnetic field, and can shrink only under a specific magnetic field, so that the drug leakage phenomenon can not occur in the motion process, and the problem of the existing magnetic control soft robot in the drug delivery field is solved.
Drawings
Fig. 1 (a) and (b) are respectively the placement modes of the hard magnetic porous material provided by the invention under two magnetic fields in different directions;
FIG. 2 is a graph showing the comparison of flexural deformations of the hard magnetic porous material provided by the invention under the action of an externally applied magnetic field;
FIG. 3 is a comparative schematic diagram of shrinkage deformation of the hard magnetic porous material according to the present invention under the action of an externally applied magnetic field;
FIG. 4 is a bulk microscope image of a cross section of a hard magnetic porous material provided by the present invention;
FIG. 5 is a three-dimensional reconstruction model of micro-CT of the hard magnetic porous material provided by the invention;
FIG. 6 is a schematic diagram of a flexible pressure capacitance sensor based on a hard magnetic porous material according to embodiment 3 of the present invention;
fig. 7 is a schematic structural diagram of a sensor module for detecting a magnetic field direction based on a hard magnetic porous material according to embodiment 4 of the present invention.
The same reference numbers are used throughout the drawings to reference like elements or structures, wherein: 110-upper electrode substrate, 120-upper electrode material, 130-hard magnetic porous material layer, 140-lower electrode material, 150-lower electrode substrate, 160-bottom plate.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
The invention provides a preparation method of a hard magnetic porous material, which comprises the steps of uniformly mixing neodymium iron boron powder with solution A of a silicon rubber material, then adding solution B of silicon rubber and a diluent, uniformly mixing, soaking square sugar blocks in the obtained mixture, soaking the liquid mixture in a vacuumizing mode, filling the used pores of the square sugar blocks, solidifying the silicon rubber material, and finally washing out square sugar with hot water to obtain the hard magnetic porous material with interconnected internal pores and uniformly distributed neodymium iron boron powder. In this embodiment, the solution a of silicone rubber is different from the solution B of silicone rubber; in one embodiment, the silicone rubber may be Ecoflex-0030, and the Ecoflex-0030A solution and the Ecoflex-0030B solution are a monomer solution of Ecoflex-0030 and a cross-linking agent solvent.
The preparation method mainly comprises the following steps:
s1, adding neodymium iron boron powder into the solution A of the silicon rubber, and uniformly dispersing to obtain a first mixture.
In this embodiment, the neodymium iron boron powder has a diameter of 5 microns; the mixing method comprises the following steps: and (3) rotating the mixture of the solution A of the neodymium iron boron powder and the silicon rubber at a high speed by using a mixing defoamer until the neodymium iron boron powder is uniformly suspended in the liquid silicon rubber, so as to ensure that the distribution of the neodymium iron boron powder in the prepared hard magnetic porous material is uniform. In general, the rotation time required for dispersing the neodymium iron boron powder into the silicon rubber is long, so that the neodymium iron boron powder is uniformly dispersed into the solution A of the silicon rubber, the solution B added with the silicon rubber can be uniformly mixed only after short-time rotation, and the mixing defoaming machine can eliminate bubbles generated in the rotation process while mixing, so that the obtained mixture can be directly used for the next operation without defoaming, and more sufficient time is provided for the subsequent operation.
S2, adding the solution B of the silicone rubber and the diluent into the first mixture, and uniformly mixing to obtain a second mixture.
In the second mixture, the mass percentage content of each reactant is as follows: 30-60% of neodymium iron boron powder, 0-12% of diluent and 37-66% of silicone rubber material, wherein the content of the silicone rubber material is the sum of the content of solution A of silicone rubber and the content of solution B of silicone rubber.
The silicone rubber used in the present embodiment is Ecoflex-0030 having a low Young's modulus; the diluent is Ecoflex-0030 or dimethyl silicone oil. It should be noted that the higher the content of the neodymium iron boron powder, the higher the rotation time and speed requirements required for mixing the neodymium iron boron powder into the silicone rubber material, when the content of the neodymium iron boron powder is higher than 60%, the neodymium iron boron powder cannot be uniformly dispersed in the silicone rubber material, and precipitation is necessarily generated; the added diluent is similar to the silicone rubber material in molecules, and is different in that the diluent is a short-chain silicone molecule, and the side chain groups and the end sealing groups are different, so that the addition of the diluent damages the proportion of the original magnetic force A, B solution of the silicone rubber, the overall crosslinking degree of the material is reduced, the Young modulus is reduced, and the curing time of the silicone rubber molecule is delayed.
S3, pouring the second mixture into a mould, and placing a sugar template into the mould.
The mold is made of polylactic acid printed in 3D, and the sugar template is a cube sugar block; the square sugar block is easy to obtain and low in cost, and meanwhile, as the square sugar block is extruded by sugar particles, the internal pores of the porous material made by taking the square sugar block as a sacrificial template are necessarily mutually connected, so that the square sugar block has good air permeability.
And S4, placing the die in a vacuum environment so that the second mixture completely fills the pores of the sugar template.
The vacuum environment is as follows: placing under vacuum degree of-0.05 mPa for thirty minutes; in a vacuum environment, the gas in the pores of the square sugar block is sucked out to form negative pressure, and the liquid mixture fills all the pores of the square sugar block under the double functions of the negative pressure and capillary force and wets the whole square sugar block.
And S5, taking the die out of the vacuum environment, standing at a preset temperature, and then heating to completely cure the silicone rubber.
Standing at a preset temperature: placing the die in an environment at 4 ℃ for 10-12 hours; the high-temperature heating method comprises the following steps: heating the mold in 75+/-5 deg.c for 2-3 hr; the low-temperature environment slows down the curing rate of the silicon rubber material, so that the silicon rubber can fully permeate into the square sugar block, and the silicon rubber can be slowly cured along with the time, so that the position of the NdFeB powder is fixed; the high-temperature heating is used for thoroughly curing the silicone rubber material which is not completely cured in the previous step, so that the porous material can maintain the self shape.
S6, taking the sugar template out of the die, and then putting the sugar template into hot water for dissolution to obtain the hard magnetic porous material.
The method for dissolving the sugar template by hot water comprises the following steps: and (3) placing the sugar template taken out in the step (S5) into a container containing water, heating and stirring by a magnetic stirrer, wherein the heating temperature is 80 ℃ and the duration is 1 hour, so that the sugar template is dissolved.
S7, placing the hard magnetic porous material into a high-voltage magnetizer for magnetization.
The hard magnetic porous material obtained by the above method has an anisotropic deformation response under a magnetic field, as shown in fig. 1, when the hard magnetic porous material is placed in the method of (a) in fig. 1, the hard magnetic porous material is not significantly deformed, and when the hard magnetic porous material is placed in the method of (b) in fig. 1, the hard magnetic porous material is significantly deformed, and the deformation characteristics of the hard magnetic porous material in this case are as shown in fig. 3, so that the release of the drug only occurs in the case of (b) in fig. 1, so that the magnetic soft robot does not leak the drug during the movement.
The hard magnetic porous material has a remarkable bending deformation phenomenon in a magnetic field due to its high coercive force, and by using the bending deformation, a magnetic field can be applied to control the rolling motion of the magnetically soft robot, as shown in fig. 2. Due to the high remanence inside the hard magnetic porous material, the magnetic soft robot based on the hard magnetic porous material has flexible motion capability, and can realize the control of the magnetic soft robot by only needing a very small magnetic field (< 100 Gs).
The invention also provides a hard magnetic porous material which is prepared by adopting the preparation method of the hard magnetic porous material.
The invention also provides application of the hard magnetic porous material in a flexible pressure capacitance type sensor, a magnetic field direction detection module and a drug delivery magnetic control soft robot.
The invention is described in further detail below with respect to a few specific examples.
Example 1
The embodiment provides a preparation method of a hard magnetic porous material, which comprises the following steps:
(S1) 5g of NdFeB powder was added to 5g of Ecoflex-0030 in solution A, and the mixture was rotated at high speed by a mixing defoamer until the mixture was uniform, to obtain a first mixture.
(S2) 5g of Ecoflex-0030B solution was added to the first mixture, and the mixture was uniformly mixed by high-speed rotation using a mixing defoamer, to obtain a second mixture.
(S3) pouring the second mixture into a polylactic acid mold printed by a 3D printer, and then putting the cube into the liquid mixture.
(S4) placing the die into a vacuum kettle, vacuumizing by a vacuum pump for maintaining-0.05 mPa for half an hour, and enabling the liquid mixture to completely fill the pores of the cube sugar.
(S5) taking out the die after the step (S4), placing in a refrigerator for 10-12 hours, taking the cube sugar out of the die, stripping off the surface silicon rubber, placing in an oven, and heating at a high temperature of 75 ℃ for 2-3 hours.
(S6) putting the square sugar blocks into a beaker containing 500ml of deionized water, putting the sesame seed cake on a magnetic stirrer, heating and stirring the magnetic stirrer at the temperature of 80 ℃ to dissolve the square sugar blocks into hot water, and changing the water for 2-3 times during the period of 1 hour to obtain the hard magnetic porous material.
(S7) putting the hard magnetic porous material into an oven, heating at 50 ℃ for 3 hours, evaporating water in the porous material, and magnetizing the porous material with a 2T magnetic field in a high-voltage magnetizer. The obtained hard magnetic porous material is shown in fig. 4 and 5.
The hard magnetic porous material prepared by the embodiment can realize ultralow Young modulus of 1.1kPa and ultralow shear modulus of 1.3kPa due to the addition of less NdFeB powder, so that the flexible pressure sensor prepared based on the hard magnetic porous material of the embodiment has the best sensitivity and the minimum detection limit, and is suitable for detecting a small-stress scene.
Example 2
The embodiment provides a preparation method of a hard magnetic porous material, which comprises the following steps:
(S1) adding 15g of neodymium iron boron powder into 5g of Ecoflex-0030A solution, and rotating at a high speed by a mixing defoamer until the powder is uniformly mixed to obtain a first mixture;
(S2) adding 5g of Ecoflex-0030B solution, 1g of Ecoflex-0030 diluent and 2g of simethicone into the first mixture, and uniformly mixing by a mixing defoamer at a high speed to obtain a second mixture;
(S3) pouring the second mixture into a polylactic acid mold printed by a 3D printer, and then putting square sugar cubes into a liquid mixture;
(S4) placing the die into a vacuum kettle, vacuumizing by a vacuum pump for maintaining-0.05 mPa for half an hour, and enabling the liquid mixture to completely fill the pores of the square sugar block;
(S5) taking out the die subjected to the step (S4), placing in a refrigerator for 10-12 hours, taking the cube sugar out of the die, stripping off the surface silicon rubber, placing in an oven, and heating at a high temperature of 75 ℃ for 2-3 hours;
(S6) putting the square sugar blocks into a beaker containing 500ml of deionized water, putting the sesame seed cake on a magnetic stirrer, heating and stirring the magnetic stirrer at 80 ℃ to dissolve the square sugar blocks into hot water, and changing the water for 2-3 times during the period of 1 hour to obtain the hard magnetic porous material;
(S7) putting the hard magnetic porous material into an oven, heating at 50 ℃ for 3 hours, evaporating water in the porous material, and magnetizing the porous material with a 2T magnetic field in a high-voltage magnetizer.
The hard magnetic porous material prepared by the embodiment has higher remanence after magnetization, which can reach 120Gs at most, because more NdFeB powder is added; meanwhile, the material benefits from the lower Young's modulus, and the material can be subjected to obvious bending deformation and shrinkage deformation in a magnetic field, so that the material is more suitable for being used as a carrier for drug delivery. In addition, higher NdFeB content enhances the dielectric properties of the hard magnetic porous material, while not as sensitive as the porous sensor prepared from the hard magnetic porous material of example 1, but with higher capacitance values and capacitance variation.
Example 3
The embodiment provides a preparation method of a flexible pressure capacitance type sensor based on a hard magnetic porous material.
As shown in fig. 6, a schematic structural diagram of a flexible pressure capacitance type sensor based on a hard magnetic porous material is shown. The sensor mainly comprises five parts, namely an upper electrode substrate 110, an upper electrode material 120, a hard magnetic porous material layer 130, a lower electrode material 140 and a lower electrode substrate 150. The materials of the upper electrode substrate 110 and the lower electrode substrate 150 are flexible PDMS films, the materials of the upper electrode material 120 and the lower electrode material 140 are conductive cloths, and the material 130 of the hard magnetic porous material layer is the same as the hard magnetic porous material prepared in example 2.
The preparation method of the flexible pressure sensor based on the hard magnetic porous material in the embodiment comprises the following specific steps:
a precursor solution of dimethyl siloxane (PDMS) with a thickness of 100 micrometers (A, B solution ratio is 10:1) is uniformly coated on a flexible PET film, the PET film is put into an oven, heated at 75 ℃ for 20min for complete curing, the PDMS film is taken off from the PET, and laser processing is performed to a shape corresponding to an electrode, so that the upper electrode substrate 110 is obtained.
A thin adhesive (siloxy) was coated on the surface of the upper electrode substrate 110, a piece of conductive cloth processed by laser was placed as the upper electrode material 120 on the surface of the PDMS thin film coated with the adhesive to form an upper electrode, and the upper electrode was placed in an oven and heated at 75 ℃ for 10min until the adhesive was cured.
Taking the hard magnetic porous material prepared in the embodiment 2 to prepare the hard magnetic porous material layer 130 as a dielectric layer of the capacitive sensor, coating a thin adhesive on the surface of the upper electrode material 120 far away from the upper electrode substrate 110, placing the hard magnetic porous material layer 130 on the surface of the upper electrode material 120, and heating at 75 ℃ in an oven for 10min until the adhesive is cured.
The lower electrode material 140 and the lower electrode substrate 150 are sequentially placed to form a lower electrode, and the upper electrode, the hard magnetic porous material, and the lower electrode are formed into a flexible pressure sensor according to the above-described method.
As shown in fig. 6, the sensor in this embodiment is a flexible pressure capacitive sensor with an adjustable detection range. Wherein, the content of NdFeB powder can improve the Young modulus of the material, enhance the dielectric property of the material, reduce the sensitivity and widen the detection range.
The capacitance value of the capacitance sensor is mainly determined by the dielectric constant of the dielectric layer and the distance between the two electrodes, and when the flexible pressure sensor is not compressed in the embodiment, the dielectric layer is composed of Ecoflex doped with magnetic powder and air because the porous material has the characteristic of high pore volume rate, and the dielectric constant of the silicon rubber material is enhanced by the magnetic powder; when the sensor is compressed, the distance between the two polar plates is reduced, air in the porous material is extruded, the dielectric constant of the dielectric layer is greatly increased, and finally, the sensor has great capacitance change, so that the hard magnetic porous material is very suitable for being used as the dielectric material of the flexible pressure sensor.
Example 4
The embodiment provides a preparation method of a magnetic field direction detection module based on a hard magnetic porous material.
As shown in fig. 7, a schematic structural diagram of the magnetic field direction detection module based on the hard magnetic porous material is shown. The magnetic field direction detection module includes two vertically disposed sensing units, each of which is divided into six parts, namely an upper electrode substrate 110, an upper electrode material 120, a hard magnetic porous material layer 130, a lower electrode material 140, a lower electrode substrate 150, and a bottom plate 160. The materials of the upper electrode substrate 110 and the lower electrode substrate 150 are flexible PDMS films, the materials of the upper electrode material 120 and the lower electrode material 140 are conductive cloths, the material of the hard magnetic porous material layer 130 is the same as the hard magnetic porous material prepared in embodiment 2, and the material of the bottom plate 160 is extruded acryl.
The specific steps of the preparation method of the magnetic field direction detection module based on the hard magnetic porous material in the embodiment are as follows:
a precursor solution of dimethyl siloxane (PDMS) with a thickness of 100 micrometers (A, B solution ratio is 10:1) is uniformly coated on a flexible PET film, the PET film is put into an oven, heated at 75 ℃ for 20min for complete curing, the PDMS film is taken off from the PET, and laser processing is performed to a shape corresponding to an electrode, so that the upper electrode substrate 110 is obtained.
A thin adhesive (siloxy) was coated on the surface of the upper electrode substrate 110, a piece of conductive cloth processed by laser was placed as the upper electrode material 120 on the surface of the PDMS thin film coated with the adhesive to form an upper electrode, and the upper electrode was placed in an oven and heated at 75 ℃ for 10min until the adhesive was cured.
The hard magnetic porous material prepared in example 2 was used to prepare the hard magnetic porous material layer 130 as a dielectric layer of the capacitive sensor, a thin adhesive was coated on the surface of the upper electrode material 120 far from the upper electrode substrate 110, the hard magnetic porous material layer 130 was placed on the surface of the upper electrode material 120, and the mixture was heated at 75 ℃ for 10min in an oven until the adhesive was cured.
The lower electrode material 140 and the lower electrode substrate 150 are sequentially placed to form a lower electrode, and the upper electrode, the hard magnetic porous material, and the lower electrode are formed into a flexible pressure sensor according to the above-described method. The extruded acrylic plate is processed into a required shape by using laser to serve as a bottom plate 160, a thin adhesive is coated on the surface of the bottom plate, a flexible pressure sensor is placed on the bottom plate, the flexible pressure sensor is placed at room temperature for a period of time until the adhesive is solidified, two sensing units are assembled, and the two sensing units are placed in a three-dimensional Hohm coil, so that the direction of a magnetic field can be detected.
As shown in fig. 7, the detection module in this embodiment is a module for detecting a magnetic field direction. Because of the low young's modulus of the hard magnetic porous material, the hard magnetic porous material will deform very significantly in the magnetic field, and therefore the detection module of this embodiment can detect very small magnetic field changes (25 Gs).
Example 5
The embodiment provides a preparation method of a dosing soft robot based on a hard magnetic porous material.
Cutting the hard magnetic porous material described in the embodiment 2 into a required shape, and magnetizing the hard magnetic porous material by a strong magnetic field magnetizer until the hard magnetic porous material is saturated; the injector is used for injecting liquid medicine into the hard magnetic porous material, the soft magnetic robot advances to the target administration position through rolling under the control of the permanent magnet, and a magnetic field in a specific direction is applied to enable the administration robot to generate shrinkage and release the medicine.
The drug delivery robot only contracts and deforms in a specific magnetic field direction, so that the magnetic soft robot can not leak drugs in the moving process; meanwhile, the hard magnetic porous material has obvious bending deformation phenomenon in a magnetic field due to the high coercive force and the low Young modulus of the hard magnetic porous material, and the bending deformation can be realized only by a very small magnetic field (< 100 Gs); by using such bending deformation, a magnetic field can be applied to control the rolling motion of the magnetically soft robot. The magnetically soft robot based on the hard magnetic porous material has flexible motion capability due to high remanence inside the hard magnetic porous material. Therefore, the soft magnetic robot based on the hard magnetic porous material according to the present embodiment is very suitable for drug delivery.
It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (9)
1. A method for preparing a hard magnetic porous material, which is characterized by comprising the following steps:
(1) Adding neodymium iron boron powder into the solution A of the silicon rubber, and uniformly dispersing to obtain a first mixture;
(2) Adding the solution B of the silicon rubber and the diluent into the first mixture, and uniformly mixing to obtain a second mixture; in the second mixture, the mass percentage content of each reactant is as follows: 30-60% of neodymium iron boron powder, 0-12% of diluent and 37-66% of silicon rubber material;
(3) Pouring the second mixture into a mold, and placing a sugar template into the mold;
(4) Placing the mold in a vacuum environment such that the second mixture completely fills the pores of the sugar template;
(5) Taking out the die from the vacuum environment, standing at a preset temperature, and then heating to cure the silicone rubber;
(6) And taking the sugar template out of the die, dissolving and removing the sugar template, and magnetizing to obtain the hard magnetic porous material.
2. The method for preparing a hard magnetic porous material according to claim 1, wherein: the neodymium iron boron powder had a diameter of 5 microns.
3. The method for preparing a hard magnetic porous material according to claim 1, wherein: the silicone rubber is Ecoflex-0030, and the diluent is Ecoflex-0030 or dimethyl silicone oil.
4. The method for preparing a hard magnetic porous material according to claim 1, wherein: the mold is a 3D printed polylactic acid, and the sugar template is a cube sugar.
5. A method of preparing a hard magnetic porous material according to any one of claims 1 to 4, wherein: the vacuum environment is as follows: placing under vacuum degree of-0.05 mPa for thirty minutes; in a vacuum environment, the gas in the pores of the sugar template is sucked out to form a negative pressure, and the liquid mixture fills all the pores of the sugar template under the dual action of the negative pressure and capillary force and wets the whole sugar template.
6. A method of preparing a hard magnetic porous material according to any one of claims 1 to 4, wherein: standing at a preset temperature: placing the die in an environment at 4 ℃ for 10-12 hours; the mold was placed in an environment of 75±5 ℃ for 2 to 3 hours to cure the silicone rubber.
7. A method of preparing a hard magnetic porous material according to any one of claims 1 to 4, wherein: the sugar template was placed in a container containing water and heated and stirred with a magnetic stirrer at 80℃for 1 hour to dissolve the sugar template.
8. A hard magnetic porous material characterized by: the hard magnetic porous material is prepared by the preparation method of the hard magnetic porous material according to any one of claims 1 to 7.
9. Use of the hard magnetic porous material of claim 8 in flexible pressure capacitive sensors, magnetic field direction detection modules and drug delivery magnetically controlled soft robots.
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| CN109306073A (en) * | 2017-07-26 | 2019-02-05 | 韩昱苏 | Hydrophobic three-dimensional porous material and its preparation method and application and blood storage bag |
| CN111964813A (en) * | 2020-08-18 | 2020-11-20 | 西安电子科技大学 | Wireless-driven high-sensitivity flexible pressure sensor and preparation method thereof |
| CN113150371A (en) * | 2021-04-09 | 2021-07-23 | 华东师范大学 | PDMS sponge-based strain sensor and preparation method thereof |
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| CN109306073A (en) * | 2017-07-26 | 2019-02-05 | 韩昱苏 | Hydrophobic three-dimensional porous material and its preparation method and application and blood storage bag |
| CN111964813A (en) * | 2020-08-18 | 2020-11-20 | 西安电子科技大学 | Wireless-driven high-sensitivity flexible pressure sensor and preparation method thereof |
| CN113150371A (en) * | 2021-04-09 | 2021-07-23 | 华东师范大学 | PDMS sponge-based strain sensor and preparation method thereof |
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| Title |
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| 磁性有序介孔碳的合成与药物载体应用;王博;莫尊理;张春;朱小波;赵国平;郭瑞斌;;材料导报(01);第46-49页 * |
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