Background technology
Hydrogel be can be in water swelling and keep large quantity of moisture and undissolvable cross linked polymer.They can be swelling to rapidly the balance volume in water, still can keep its shape and three-dimensional space network structure, and the deswelling of dewatering under certain condition, are that a class set suction, water conservation, slow release are in the functional high molecule material of one.Owing to containing large quantity of moisture in cross-linked network, hydrogel is extremely similar to biological tissue, its softness, moistening the surface and with the tissue affinity greatly reduced the stimulation of material to surrounding tissue, make hydrogel have good biocompatibility and histocompatibility.Therefore, hydrogel is very extensive in the purposes of biomedical aspect, can be used as microorganism immobilization carrier, medicinal slow release agent, contact lenses, artificial blood plasma, artificial skin, tissue engineering bracket material etc.
CNT is the airtight nanometer body that is bent to form by single or multiple lift six-membered carbon ring graphite linings, and the two ends of pipe are respectively the hemispherical end-blocking of similar half fullerene molecule, and draw ratio is generally greater than 1000.The structure that has sealing due to CNT, so axial strength and elastic modelling quantity that it has are high, higher more than 100 times than the intensity of steel, theoretical Young's modulus can be up to 1.8 * 10
12Pa, and proportion only has 1/6~1/7 of steel, is the material that has at present high specific strength.CNT has the basic effects such as skin effect that general nano material has, small-size effect, and has the performances such as excellent mechanics, electricity, optics, magnetics, calorifics, is suitable as very much the reinforcing material of other materials.It is acidproof, alkaline-resisting, high temperature resistant for what is more important, has higher chemical stability and good biocompatibility, and as bio-medical material, it is very favourable being applied to the human internal environment for CNT for this.
Strengthen composite aquogel by the preparation CNT, can be when keeping the hydrogel good biocompatibility, greatly improve its mechanical property and electric property, obtain the bio-medical material of excellent performance, enlarge hydrogel drug release carrier, various soft/application of the aspects such as hard tissue regeneration reparation and organizational project organ culture.
CNT has skin effect and bulk effect, its granule is little, specific surface area is large, has very strong Van der Waals force between pipe, be easy to form aggregate, thereby with the recombination process of polymer in agglomeration usually appears, be combined with polymer not tight, thereby affected the reinforced effects of CNT in matrix and the performance of performance.Existing carbon nanotube chemical modification and purification process technology all fail effectively to solve this difficult problem.And in many important application scenarios, need overlength, continuous CNT long filament and the aligned carbon nanotube film of Centimeter Level area, just can give full play to the performance such as mechanics, electricity, calorifics of CNT uniqueness.In addition, the aligned carbon nanotube preparation method and the application in the bio-medical field thereof that strengthen hydrogel composite material yet there are no bibliographical information so far.
Summary of the invention
The preparation method that the purpose of this invention is to provide a kind of biocompatible directional carbon nanotube array reinforced composite hydrogel, make the directional carbon nanotube array reinforced composite hydrogel of preparing when keeping hydrogel intrinsic biocompatibility and histocompatibility, improve its mechanical property and electric property, and can according to requirements regulate and control above-mentioned performance.
The present invention adopts the standby directional carbon nanotube array reinforced composite hydrogel of chemical vapour deposition (CVD) (CVD) technology, crosslinking with radiation technology and freeze-thaw legal system.Processing step is as follows:
Step 1: preparation directional carbon nanotube array
Adopt chemical vapour deposition (CVD) (CVD) technology to prepare directional carbon nanotube array.The heating of employing resistance furnace uses quartz glass tube as reactor.With the growth substrate of quartz glass plate as aligned carbon nanotube, be equipped on quartz boat, be placed in the middle of reative cell.Carbon source, catalyst and carrier gas (hydrogen and argon) are introduced from an end of quartz ampoule, and tail gas is discharged from the other end.Carbon source is carbon monoxide or Hydrocarbon such as methane, ethane, ethylene, propylene etc., controls the flow of carbon source with the mass flowmenter control valve.If working load type catalyst needs in advance catalyst to be coated onto in substrate; If use floating catalyst, need a spraying system (as accurate flow pump) with the gasification catalyst injection in the carbon source air-flow.Usually the growing method of aligned carbon nanotube is first to reach reaction temperature with argon or other inert gas purge reactor to reactors, then gas is switched to carbon source, until directional carbon nanotube array growth is switched back gas noble gas and is cooled to room temperature, the taking-up sample after complete.The CNT of preparing in this way be generally multi-walled carbon nano-tubes (external diameter scope 5~100nm), the growth length of CNT depends on the supply of carbon source, even its growth length can reach 6mm.
Step 2: preparation polymeric sol
Analytically pure high molecular polymer is added in redistilled water, be mixed with the high molecular polymer mass fraction and be 5~40% aqueous solution, be stirred to the solid polymer uniform dissolution in 50~95 ℃ of waters bath with thermostatic control, perhaps put into the dissolving of steam vessel in heating, container inner pressure maintains 0.08~0.12MPa, temperature is 100~120 ℃, 0.5~2 hour heat time heating time.At last, the polymeric sol that is uniformly dissolved is standing cooling at room temperature, drain to bubble.
described high molecular polymer is the avirulent high molecular polymer that is suitable for biomedicine field, can be polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), Polyethylene Glycol (PEG), polyacrylamide (PAM), polyacrylic acid (PAA), polyvinyl methyl ether (PVME), polyethylene glycol oxide (PEO), chitosan (chitosan), water-soluble chitosan (ws-chitin), collagen (collagen), gelatin (gelatin), hyaluronic acid (HA), a kind of in alginate and fibrin or by above-mentioned any two kinds of mixture that form to five kinds of macromolecular materials.
Step 3: polymeric sol is infiltrated in the CNT precast body
To be dispersed in by the directional carbon nanotube array that step 1 makes in plane mould, slowly infiltrate polymeric sol again in mould, the mass ratio of CNT and polymeric sol is 0.01/99.99~20/80, makes polymeric sol enveloped carbon nanometer tube precast body, obtains mixture.
Step 4: the standby CNT composite aquogel of freeze-thaw method or crosslinking with radiation legal system
Method 1: the mixture that step 3 is obtained carries out the freeze-thaw circulation processing.Cryogenic temperature-35~-5 ℃, then cooling time 5~24 hours at room temperature thawed 1~12 hour, and so freeze-thaw circulation is 1~8 time, obtains directional carbon nanotube array reinforced composite hydrogel.It is polyvinyl alcohol (PVA) or the high polymer mixtures that contains polyvinyl alcohol that the method mainly is applicable to matrix.
Method 2: before the freeze-thaw circulation that carries out method 1 is processed or after it, the hydrogel that the mixture that step 3 is obtained or method 1 obtain carries out RADIATION PROCESSING, adopting dosage is gamma-rays, electron beam, X ray or the ultraviolet irradiation mixture of 10~100kGy, by strengthening the chemical crosslinking effect between high molecular polymer, further improve the mechanical strength of hydrogel.It is polyvinyl alcohol (PVA) or the high polymer mixtures that contains polyvinyl alcohol that the method mainly is applicable to matrix.
Method 3: adopt gamma-rays, electron beam, X ray or ultraviolet to carry out RADIATION PROCESSING to the mixture that step 3 obtains, dosage is 10~100kGy, obtains directional carbon nanotube array reinforced composite hydrogel.It is described various high molecular polymers of step 2 and composition thereof that the method is applicable to matrix.
The directional carbon nanotube array reinforced composite hydrogel thickness that adopts the present invention to make is 10~3000 μ m.The moisture mass percent of matrix phase hydrogel is 60~99%.
The present invention compared with prior art has following advantage and beneficial effect:
Adopt chemical gaseous phase depositing process to prepare directional carbon nanotube array, controlled the growth of CNT by the supply of carbon source, reach the controlled purpose of length of carbon nanotube.Adopt the polymeric sol infiltration method that polymeric sol is infiltrated in the CNT precast body, overcome the reunion entanglement problems that CNT and polymer recombination process occur, promote the combination of CNT and matrix hydrogel, improved the boundary strength of wild phase and matrix phase.The CNT that aligns in matrix can be given full play to the excellent properties of CNT aspect mechanics, electricity, improves comprehensive mechanical property and the electric conductivity of hydrogel.Adopt the standby composite aquogel of freeze-thaw method and crosslinking with radiation legal system, strengthened the crosslinked action between high molecular polymer, the method does not contain any chemical addition agent simultaneously, and is nontoxic, satisfies the requirement of biocompatibility.In addition, by controlling the addition of aligned carbon nanotube, can change content and the distribution of CNT in matrix; The parameters such as the radiation dose when controlling crosslinking with radiation and the temperature of freeze-thaw process, time, cycle-index can change condensed state structure and the crystallization degree of high molecular polymer, thereby reach the controlled purpose of composite aquogel performance of preparing.
The present invention is fit to be applied to the bio-medical such as artificial articular cartilage, tissue engineering bracket, neurocyte carrier, bionical implant electrode material field.
The specific embodiment
Example 1
Step 1: take ferrocene powder 5g, be dissolved in 50mL dimethylbenzene.Form brown color clear solution, standing 36 hours after mix homogeneously.Quartz glass plate is equipped on quartz boat, slowly pushes in the middle part of the chemical vapor deposition unit reative cell, with the two ends of fluid sealant sealing quartz ampoule.Pass into argon, flow is 100mL/min, reacting by heating chamber to 900 ℃.The adjustment argon flow amount is 2000mL/min, and passes into the hydrogen of 400mL/min.Mobile quartz ampoule is adjusted the capillary tube opening with respect to the position of burner hearth, makes the registration of thermocouple remain on 250~300 ℃, guarantees that reaction solution can be vaporific spraying into.Open accurate flow pump, make ferrocene/dimethylbenzene reactant solution be vaporific by capillary tube and spray in reative cell, the solution feed speed is 0.4mL/min.React complete, stop passing into hydrogen, turn the flow of argon down to 100mL/min, make reative cell be cooled to room temperature in argon gas atmosphere, take out sample, obtain directed array of multi-walled carbon nanotubes.
Step 2: polyvinyl alcohol (PVA) solid particle is mixed with redistilled water, make the PVA mass fraction and be 20% PVA aqueous solution, put into the dissolving of steam vessel in heating, container inner pressure maintains 0.1MPa, temperature is 120 ℃, 1.5 hours heat time heating times.Then the PVA polymeric sol that is uniformly dissolved is taken out, standing cooling.
Step 3: take a certain amount of directed array of multi-walled carbon nanotubes and be dispersed in plane mould, with the PVA polymeric sol by mold side along slowly injecting mould, make it evenly to coat directional carbon nanotube array, the mass percent of CNT and polymeric sol is 0.5/99.5.
Step 4: mould is put into freezing 10 hours of the environment of-26 ℃, then at room temperature thawed 4 hours, so circulating frozen thaws 5 times, obtains directed array of multi-walled carbon nanotubes enhanced polyethylene alcohol composite aquogel.
The test result demonstration, after adding CNT, the hot strength of composite aquogel is 5.4MPa, tearing strength is 9.8kN/m, compares with 4.0kN/m with the 1.2MPa of polyvinyl alcohol hydrogel (not adding CNT), has improved respectively 350% and 145%.Aspect electric property, after adding CNT, the high frequency of composite aquogel (>1000Hz) order of magnitude of electrical impedance is by 10 of polyvinyl alcohol hydrogel
4Drop to 10
3, conductive capability raises.
Example 2
Step 1: take ferrocene powder 6g, be dissolved in 50mL dimethylbenzene.Form brown color clear solution, standing 30 hours after mix homogeneously.Quartz glass plate is equipped on quartz boat, slowly pushes in the middle part of the chemical vapor deposition unit reative cell, with the two ends of fluid sealant sealing quartz ampoule.Pass into argon, flow is 100mL/min, reacting by heating chamber to 900 ℃.The adjustment argon flow amount is 1000mL/min, and passes into the hydrogen of 150mL/min.Mobile quartz ampoule is adjusted the capillary tube opening with respect to the position of burner hearth, makes the registration of thermocouple remain on 200 ℃, guarantees that reaction solution can be vaporific spraying into.Open accurate flow pump, make ferrocene/dimethylbenzene reactant solution be vaporific by capillary tube and spray in reative cell, the solution feed speed is 0.4mL/min.React complete, stop passing into hydrogen, turn the flow of argon down to 100mL/min, make reative cell be cooled to room temperature in argon gas atmosphere, take out sample.Obtain directed array of multi-walled carbon nanotubes.
Step 2: analytically pure polyvinylpyrrolidone (PVP) granule is added in redistilled water, be mixed with the PVP mass percent and be 8% aqueous solution, stir in 60 ℃ of waters bath with thermostatic control to the PVP dissolving, obtain the PVP polymeric sol.
Step 3: take a certain amount of directed array of multi-walled carbon nanotubes and be dispersed in flat glass culture dish, the PVP polymeric sol is slowly injected by the culture dish edge, make it evenly to coat directional carbon nanotube array, the mass percent of CNT and polymeric sol is 5/95.
Step 4: the culture dish sealing is placed on carries out radiation treatment in radiation field, dosage 20kGy obtains directed array of multi-walled carbon nanotubes enhanced polyethylene ketopyrrolidine composite aquogel.
The test result demonstration, after adding the CNT that aligns, the coefficient of friction of composite aquogel drops to 0.09 by 0.25 of matrix hydrogel (not adding CNT), and the greasy property of hydrogel improves.And the elastic modelling quantity of composite aquogel rises to 3.0MPa by 1.0MPa, and hot strength rises to 4.2MPa by 0.7MPa, and comprehensive mechanical property improves.
Example 3
Step 1: even quartz glass plate sprinkled with the Co/ silica-gel catalyst is equipped on quartz boat, slowly pushes in the middle part of the chemical vapor deposition unit reative cell, with the two ends of fluid sealant sealing quartz ampoule.Pass into argon, flow is 100mL/min, reacting by heating chamber to 700 ℃.The adjustment argon flow amount is 1000mL/min, and passes into hydrogen and the acetylene gas mixture of 150mL/min.React complete, stop passing into hydrogen and acetylene gas mixture, turn the flow of argon down to 100mL/min, make reative cell be cooled to room temperature in argon gas atmosphere, take out sample.Obtain directed array of multi-walled carbon nanotubes.
Step 2: analytically pure polyvinylpyrrolidone (PVP) powder is added in redistilled water, be mixed with the PVP mass percent and be 5% aqueous solution, stir in 60 ℃ of waters bath with thermostatic control to PVP and dissolve, add polyvinyl alcohol (PVA) solid particle in PVP solution, making the quality percentage composition of PVA is 10%, after stirring, mixed liquor is put into the dissolving of steam vessel in heating, and container inner pressure maintains 0.1MPa, 120 ℃ of temperature, 1.5 hours heat time heating times.Subsequently polymeric sol is taken out, standing cooling.
Step 3: take a certain amount of directed array of multi-walled carbon nanotubes and be dispersed in plane mould, with the PVA-PVP polymeric sol by mold side along slowly injecting mould, make it evenly to coat directional carbon nanotube array, the mass percent of CNT and polymeric sol is 1.5/98.5.
Step 4: mould is put into freezing 12 hours of the environment of-26 ℃, then at room temperature thawed 3 hours, so circulating frozen thaws 6 times, obtains directed array of multi-walled carbon nanotubes enhanced polyethylene alcohol/polyvinylpyrrolidone composite aquogel.
Test result shows, the hot strength of CNT composite aquogel rises to 6.0MPa by the 1.0MPa of matrix hydrogel (not adding CNT), high frequency (>1000Hz) order of magnitude of electrical impedance is by 10 of matrix hydrogel
4Reduce to 10
3, conductive capability strengthens.
Example 4
Step 1: take ferrocene powder 7g, be dissolved in 50mL dimethylbenzene.Form brown color clear solution, standing 28 hours after mix homogeneously.Quartz glass plate is equipped on quartz boat, slowly pushes in the middle part of the chemical vapor deposition unit reative cell, with the two ends of fluid sealant sealing quartz ampoule.Pass into argon, flow is 100mL/min, reacting by heating chamber to 900 ℃.The adjustment argon flow amount is 1000mL/min, and passes into the hydrogen of 150mL/min.Mobile quartz ampoule is adjusted the capillary tube opening with respect to the position of burner hearth, makes the registration of thermocouple remain on 200 ℃, guarantees that reaction solution can be vaporific spraying into.Open accurate flow pump, make ferrocene/dimethylbenzene reactant solution be vaporific by capillary tube and spray in reative cell, the solution feed speed is 0.4mL/min.React complete, stop passing into hydrogen, turn the flow of argon down to 100mL/min, make reative cell be cooled to room temperature in argon gas atmosphere, take out sample.Obtain directed array of multi-walled carbon nanotubes.
Step 2: analytically pure chitosan powder is added in 2% acetum, be mixed with chitosan mass percent and be 8% acid solution, stir in 50 ℃ of waters bath with thermostatic control to the chitosan dissolving, obtain the chitosan acid solution.
Step 3: take a certain amount of directed array of multi-walled carbon nanotubes and be dispersed in flat glass culture dish, chitosan solution is slowly injected by the culture dish edge, make it evenly to coat directional carbon nanotube array, the mass percent of CNT and chitosan solution is 2/98.
Step 4: the culture dish sealing is placed on carries out radiation treatment in radiation field, dosage 30kGy makes chitosan molecule be cross-linked to form gel.
Step 5: the composite aquogel that makes was at room temperature used distilled water immersion 3 days, and refresh the water periodically, make the faintly acid soak become neutrality, obtain directed array of multi-walled carbon nanotubes and strengthen the chitosan composite aquogel.
Example 5
Step 1: take ferrocene powder 4g, be dissolved in 50mL dimethylbenzene.Form brown color clear solution, standing 25 hours after mix homogeneously.Quartz glass plate is equipped on quartz boat, slowly pushes in the middle part of the chemical vapor deposition unit reative cell, with the two ends of fluid sealant sealing quartz ampoule.Pass into argon, flow is 100mL/min, reacting by heating chamber to 900 ℃.The adjustment argon flow amount is 2000mL/min, and passes into the hydrogen of 400mL/min.Mobile quartz ampoule is adjusted the capillary tube opening with respect to the position of burner hearth, makes the registration of thermocouple remain on 250~300 ℃, guarantees that reaction solution can be vaporific spraying into.Open accurate flow pump, make ferrocene/dimethylbenzene reactant solution be vaporific by capillary tube and spray in reative cell, the solution feed speed is 0.4mL/min.React complete, stop passing into hydrogen, turn the flow of argon down to 100mL/min, make reative cell be cooled to room temperature in argon gas atmosphere, take out sample, obtain directed array of multi-walled carbon nanotubes.
Step 2: be that polyethylene glycol oxide (PEO) and the polyvinyl alcohol (PVA) of 6: 4 is dissolved in redistilled water with mass ratio, the solution of preparation macromolecule mixture mass fraction 15%.Heated and stirred is even, obtains the PEO-PVA mixed solution.
Step 3: take a certain amount of directed array of multi-walled carbon nanotubes and be dispersed in flat glass culture dish, the PEO-PVA mixed solution is slowly injected by the culture dish edge, make it evenly to coat directional carbon nanotube array, the mass percent of CNT and mixed solution is 7/93.
Step 4: culture dish is put into freezing 12 hours of the environment of-20 ℃, then at room temperature thawed 5 hours, so circulating frozen thaws 4 times.Culture dish after sealing again is placed in radiation field and carries out the electron beam irradiation processing, and dosage 40kGy obtains directed array of multi-walled carbon nanotubes and strengthens polyethylene glycol oxide/polyvinyl alcohol composite hydrogel.