CN101034079A - Judgement and control method for carbon nano-tube electrophoretic liquid concentration - Google Patents
Judgement and control method for carbon nano-tube electrophoretic liquid concentration Download PDFInfo
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Abstract
This invention relates to a display cathode baseplate carbon nanometer tubal electrophoresis liquid concentration judging and controlling means, the steps as follows: (1) prepare indices electrophoresis liquid, and set electrophoresis condition, optimize ethanol solution which has 0.025 weight percent magnesium nitrate, 0.0125 weight percent carbon nanometer tube as indices solution; apply 10 volt per millimeter stationary electric field on electrode;(2) carry out electrophoresis to indices solution, at the same time expresses electric current I of infancy unit time as function of time T, found equation Ii=Ii (t);(3) carry out series batch electrophoresis to this solution, found function of batch electrophoresis liquid: Ib=Ib (t);(4) comparing once term ratio with constant term ratio of Ib(t) and Ii(t), if ratio discrepancy greater than 5 percent, then (5) calculate assistance salinity of batch solution, and add nanometer tube and assistance salt, get batch solution to approach indices solution.
Description
Technical field
The present invention relates to a kind of preparation method of Field Emission Display, particularly a kind of preparation method of cathode of field emission display substrate carbon nano-pipe electronic emission source.
Background technology
The development of electronic product at present is many to be trend with compact, but the conventional cathode ray tube display is bulky, carrying inconvenience and quite taking up space, for with the conventional cathode ray tube complanation, develop to have low conducting electric field, the carbon nano-tube field emission display of high emission current density characteristic (Carbon Nano Tube Field Emission Display, CNT-FED).It also is to utilize electric field to excite cathode electronics, the light-emitting phosphor of impinge anode.A Field Emission Display has hundreds thousand of initiatively cold emission, and cathode-ray tube (CRT) is only by single electron gun divergent bundle, control the electronics direction by deflection yoke (Deflection Yoke), so Field Emission Display can reach than cathode-ray tube (CRT) and saves the long-pending effect of multiaspect more.Therefore, the image quality of Field Emission Display is similar to cathode-ray tube (CRT), has power saving and advantage such as light and handy again.
Carbon nano-tube field emission display with carbon nano-tube as electron emission source, therefore be laid with carbon nano-tube on its cathode base, the method of laying carbon nano-tube on cathode base has multiple, is made in the method that method on each cathode conductive layer in plain or spraying carbon nano-tube solution collocation guard are made as chemical vapor deposition (chemical vapor deposition) or with photosensitive type carbon nano-tube solution totemization.If electron emission source structure with three-electrode field transmitting display device, desire is laid in carbon nano-tube on three utmost point cathode electrode structures, and above-mentioned method for making cost is too high, and is subject to spatial structure, when making large-sized electron emission source, more be difficult to realize the homogeneity of cathode base.Electrophoretic deposition EPD method for making (Electrophoresis Deposition) can solve the problem of large scale making and cost.Open as the application for a patent for invention of the US2003/0102222 U.S., this invention is that carbon nano-tube is formulated as the alcohols aaerosol solution as electrophoresis liquid, and adding magnesium, lanthanum, yttrium, aluminium plasma salt is as auxiliary salt (Charger), cathode base to be deposited is linked to each other with electrode and be positioned in this electrophoresis liquid, and apply direct current or alternating voltage to described electrode, in solution, to form electric field, the auxiliary salt ion that ionization goes out in solution is attached on the carbon nanotube dust, because it is moving to carry out electrophoresis that described ion can be subjected to electric field action, thereby carbon nano-tube is deposited on electrode, can on this cathode base electrode, forms the carbon nano-tube deposition patterns thus.
Because electrophoretic deposition can be deposited on the carbon nano-tube pattern on the electrode layer, and can avoid because of the restriction of three-electrode field transmitting display device on cathode construction, so electrophoretic deposition has been widely used in the making of the carbon nano-tube of cathode base.Carrying out along with electrophoretic deposition process, auxiliary salt is deposited on the electrode with carbon nano-tube to be deposited gradually, make auxiliary salt ion and carbon nano-tube concentration in the solution reduce gradually, also change owing to auxiliary salt moves the moving electric current and voltage of electrophoresis that produces thus thereupon, make the deposition efficiency of carbon nano-tube reduce.
Therefore, the electrophoretic techniques polygamy closes the setting of power supply unit, carries out the electrophoresis processing procedure with specific voltage or specific currents earlier, produces electrophoretic deposition on the electrode base board surface after a period of time.Yet the deposition gradually of auxiliary salt ion in the electrophoresis liquid and carbon nano-tube will make the solute (auxiliary salt and carbon nano-tube) in the solution reduce gradually, the influence that produces because solute concentration changes in order to solve generally mostly is by revising the power values that is provided or the mode that compensates solute adjusted.The former is as raising voltage or electric current, or the increase electrophoresis time; The latter regularly replenishes solute or changes solution.
Yet, no matter be to revise voltage or electric current or compensatory add solute, still there are problems in these adjustment with respect to the continued operation processing procedure.To revise electric current and voltage, when auxiliary salt concentration reduces, keep a certain amount of for making electrophoretic deposition, need to increase voltage or electric current.Yet ethanolic solution is inflammable, increases electric current and easily causes burning; If with water is solvent, the water effect that then can produce electrolysis is unfavorable for sediment.Moreover, if increase electrophoresis time, then be easy to generate deposition inequality or polarization effect, so electrophoresis is deposited as the best to finish at short notice.
From another point of view,, then must have auxiliary judgment mechanism, to obtain best replenishing opportunity if will replenish the auxiliary salt of minimizing or the concentration of carbon nano-tube at electrophoretic deposition process.The practice of conventional cathode substrate preparation is that cathode base is taken out after 10 minutes at electrophoresis, carries out the deposition (in conventional art usually carry out three time can realize uniform deposition effect) of batch processing for several times to realize even effect again.Therefore, traditional solute concentration adjustment needs to judge by inspecting adjusted cathode base deposition results, therefore loses time, and can't satisfy the production demand of continuous electrophoresis deposition.
Summary of the invention
For addressing the above problem, a cover electrophoretic liquid concentration judgment mechanism need be set up, thereby auxiliary salt and carbon nano-tube can be replenished in good time, so that the solute concentration in the electrophoresis liquid can be kept is a certain amount of, make electrophoretic deposition react sustainable carrying out.Therefore, fundamental purpose of the present invention is to provide a kind of solute concentration judgment mode of electrophoresis liquid, thereby sets up a kind of electrophoretic deposition method for making of cathode of field emission display electron emission source.Described method provides a kind of judgment mechanism of electrophoretic liquid concentration, to replenish auxiliary salt and carbon nano-tube in electrophoresis liquid in good time, makes that electrophoretic deposition is sustainable to carry out.Because in the electrophoretic deposition process, the variation of voltage or electric current is relevant with the concentration of auxiliary salt in the solution, lunar calendar the present invention utilizes electric current and time relation, judges whether solution concentration still can deposit good carbon nano-tube on cathode base.
Because in the electrophoresis process, voltage or electric current variation are directly proportional with the concentration of auxiliary salt in the solution, therefore the present invention utilizes this characteristic, continuing the record electric current changes, replenish the foundation of auxiliary salt and carbon nano-tube as electrophoresis process with this, thereby electrophoretic deposition was finished in the controllable time, satisfied the volume production requirement.In addition, mode can be made electron emission source by continuous batch of electrophoresis, and can predict the variation of effects of ion concentration, and suitably be adjusted according to this, makes electrophoretic liquid concentration maintain certain limit, thereby can carry out electrophoresis continuously.
Therefore, control method step of the present invention comprises:
(1) preparation index electrophoresis liquid, and set deposition condition; Wherein, this index solution is that the magnesium nitrate percentage by weight is 0.025%, and the carbon nano-tube percentage by weight is 0.0125% ethanolic solution; Simultaneously, the present invention carries out electrophoresis in stationary electric field, and this electric field is 10 volts/millimeter; In addition, duty factor (duty factor) is set at 1/5 (on/total), and electric voltage frequency is got 250Hz.
(2) index solution is carried out electrophoresis.Obtain electric current and the value of time in the unit interval at initial stage simultaneously, and reometer is shown the function of time, promptly set up equation I with the Return Law
i=I
i(t).In a preferred embodiment, this unit interval is 60 seconds, and this electric current is to note down once per 5 seconds simultaneously.
(3), and similarly in the time interval, set up the function I of this batch electrophoresis liquid in same units to continuous batch of electrophoresis of this solution
b=I
b(t), and
(4) calculate I respectively
b(t) and I
i(t) once ratio and constant term ratio, and described two ratios are compared, to infer effects of ion concentration service limits.If this constant term differs more than 5%, then with once coefficient ratio
(5) calculate the auxiliary salt concentration of current solution, and additional carbon nano-tube and auxiliary salt, with near index solution, thereby be beneficial to the carrying out of electrophoresis next time.
Description of drawings
Fig. 1 is experimental data of the present invention (one);
Fig. 2 is the x-y graph of a relation of Fig. 1 experimental data;
Fig. 3 is experimental data of the present invention (two);
Fig. 4 is the x-y graph of a relation of Fig. 3 experimental data;
Fig. 5 is a process flow diagram of the present invention.
In the accompanying drawing, the list of parts of each label representative is as follows:
40...... beginning
41...... preparation index electrophoresis liquid
42...... setting deposition condition
44...... carry out electrophoresis
45...... record index solution electric current and time relation
46...... set up index solution initial stage function
47...... record batch solution electric current and time relation
48...... set up batch solution function
50...... whether the coefficient ratio of function equates
52...... calculate current auxiliary salt concentration
54...... add auxiliary salt and carbon nano-tube
Embodiment
Because solution ion concentration constantly changes in the electrophoresis process, therefore can't be only by ion concentration or present situation in the single electrical information discriminating solution.The present invention fixes electric field, in order to the variation of inferring effects of ion concentration with electrorheologicalization.Below will sketch actual practice.
If fixedly carrying out repeatedly cathode base electrophoresis under the electrophoresis liquid measure, and each electrophoretic deposition time is all consistent, then can deposit desirable cathode electronics emissive source.Under such condition, note down the electric current and the time of every each electrophoretic deposition, and unit interval electric current and time relation be shown as with function table:
I＝I(t)＝α+βt (1)
Under the auxiliary salinity of difference, coefficient entry (α
1, β
1), (α
2, β
2) ratio and concentration proportional.The present invention is according to this proportional relation, by making auxiliary salt concentration between between rational bound, and by continuing to add auxiliary salt and carbon nano-tube, makes the solute concentration of electrophoresis liquid be maintained at particular value, to produce best electrophoretic effects.Therefore but the present invention's continuous electrophoresis deposition cathode substrate reaches mass production.
In the starting stage of electrophoresis process, during extra electric field, the zwitterion of auxiliary salt will be subjected to electric field influence and to two electro-depositions in the solution, and it is moving to form electrophoresis, have this moment obvious electric current trend to change.It is a certain amount of to treat that the electrode surface ion deposition reaches, or the salt ionic concentration that dissociates in the solution gradually reduces, this moment since the ion deposition amount equate with the amount of dissociating, be equilibrium state, so the electric current variation eases up.This variation has repeatability.Therefore, can be write as the form of function with electric current I in the unit interval and electrophoresis time t to return convergence:
I＝α
0+α
1t+α
2t
2+α
3t
3 (3)
Wherein, the coefficient of high-order term all omits owing to too little.
Therefore, the present invention is set in fixed value with electric field, utilizes stationary electric field to carry out electrophoresis, and by the moving cathode base that is deposited on of the electrophoresis of auxiliary salt ion.Described zwitterion is deposited on electrode gradually, cause the auxiliary salt ion concentration in this electrophoresis liquid to descend, so electric current will decrease.Because but by the reometer detected current value on the power supply unit, what therefore can obtain time and electric current concerns that chart is to infer solution concentration.Below will enumerate actual experiment illustration, the relation of electric current and auxiliary salt concentration will be described.
Below respectively with solution A, solution B, and solution C as electrophoresis liquid and carry out the sedimentation experiment of carbon nano-tube in cathode base.It is solvent with ethanol, magnesium nitrate (MagnesiumNitrate, Mg (NO
3)
2) be auxiliary salt, and add carbon nano-tube, the electrophoresis liquid of modulation A, B, three kinds of variable concentrations of C.Wherein, solution A is the index solution of general electrophoresis carbon nano-pipe electronic emission source, is deposited as the best with the cathode base of this concentration electrophoresis gained; And solution B and solution C are simulation solution.In addition, be the deposition of the carbon nano-tube that obtains the best cathodes substrate, the percentage by weight of magnesium nitrate and carbon nano-tube is a certain value.In index solution of the present invention, the percentage by weight of magnesium nitrate is 0.025%, and the percentage by weight of carbon nano-tube is 0.0125%, and the ratio of the two percentage by weight is 2, that is,
Solution B and solution C are the solution behind the simulation solution A process electrophoresis, or carry out the solution of electrophoresis for the second time once more.Because this carbon nano-tube and magnesium nitrate are through after depositing, concentration reduces, so the solute concentration of solution B and solution C is low than the index solution A all.Deposition condition of the present invention is as follows:
Electric field=10 volt/millimeter
Duty factor=1/5 (on: total)
Electric voltage frequency=250Hz
Condition according to this, the solution of optimal deposition is that auxiliary salt concentration is between 0.02%～0.03%.
Fig. 1 is in one minute electrophoretic deposition initial stage, the elapsed time t when A, B, three kinds of solution electrophoresis of C and the list of electric current I relation, and wherein current unit is a milliampere, chronomere is second.According to the data of Fig. 1, can produce the graph of a relation of time t and electric current I, as shown in Figure 2.As can be seen from Figure, the relation of this time t and electric current I slightly is linear.
Linear in order further to prove electric current I and time t, with the electric current I (mA) of index solution (A solution) and the respective value of electrophoresis time t (sec), it is as follows to obtain quintic equation formula I (t) in the recurrence mode according to Fig. 1:
I
A(t)＝-3×10
-7t
5+6×10
-5t
4-0.0036t
3+0.1012t
2-1.5637t+110.14 (5)
Wherein, each repeatedly side's coefficient and the once ratio calculation following (disregarding positive and negative) of a coefficient:
Quadratic term coefficient: coefficient=0.1012: 1.5637 ≈ 6.47 * 10 once
-2
Cubic term coefficient: coefficient=3.6 * 10 once
-3: 1.5637 ≈ 2.30 * 10
-3
Four item coefficients: coefficient=6 * 10 once
-5: 1.5637 ≈ 3.83 * 10
-5
Five item coefficients: coefficient=3 * 10 once
-7: 1.5637 ≈ 1.92 * 10
-7
That is, quadratic term differs two magnitudes (Order) with once coefficient, and cubic term differs three magnitudes with once coefficient, and four items differ five magnitudes with once coefficient, and five items differ seven magnitudes with once coefficient.Therefore it is more not remarkable that we can inference obtain the coefficient of Gao Xiangci more.Simultaneously and since each repeatedly coefficient of side differ two magnitudes with the coefficient of first power item at least, so it can regard not influential item as.Electric current I of this index solution (A solution) and the relation equation of time t can be written as thus:
I
A(t)≈110.14-1.5637t (6)
Thereby the electric current I of A solution
AT has linear relationship with the time.
Same, repeat above-mentioned steps again, prove that the electric current I (mA) of B solution and electrophoresis time t (sec) are also linear.At first, obtain quintic equation formula I in the recurrence mode
B(t) as follows:
I
B(t)＝-5×10
-7t
5+7×10
-5t
4-0.0037t
3+0.0843t
2-1.2493t+88.889 (7)
Wherein, each repeatedly side's coefficient and the once ratio calculation following (disregarding positive and negative) of a coefficient:
Quadratic term coefficient: coefficient=0.0843: 1.2493 ≈ 6.75 * 10 once
-2
Cubic term coefficient: coefficient=0.0037: 1.2493 ≈ 2.96 * 10 once
-3
Four item coefficients: coefficient=7 * 10 once
-5: 1.2493 ≈ 5.60 * 10
-5
Five item coefficients: coefficient=5 * 10 once
-7: 1.2493 ≈ 4.00 * 10
-7
That is, quadratic term, cubic term, four items, and five items differ two respectively more than the magnitude with once coefficient.Its result and A solution are similar.Thus rationally inference more the influence of the coefficient of Gao Xiangci will be more not remarkable.So electric current I of B solution
BCan be written as with the relation equation of time t:
I
B(t)≈88.8889-1.2493t (8)
So electric current I of B solution
BT has linear relationship with the time.
In summary, from the 6th formula and the 8th formula as can be known, under The reasonable operating conditions, (decide electric field, duty factor and electric voltage frequency in particular range), solute concentration in the electrophoresis liquid is if (percentage by weight of magnesium nitrate is 0.02%～0.025% within the specific limits, the percentage by weight of carbon nano-tube is 0.01%～0.0125%), its electrophoresis time and electric current are with linear, that is:
I(t)＝α+βt (1)
It should be noted that the auxiliary salt concentration ratio 0.020 of B, A solution: 0.025=0.80 in addition, and its constant term with a coefficient score once is not:
So its equational coefficient ratio α
A: α
BAnd β
A: β
AAll satisfy the concentration ratio of auxiliary salt, that is:
C solution is auxiliary salt and the very low electrophoresis liquid of carbon pipe concentration, and this solution can't carry out electrophoresis with the deposition condition of present setting.And the equation I that pushes away by the electric current and the data of time of C solution
C(t), its every coefficient value of comparing gained with index solution does not satisfy the relation of formula 9.Therefore, can't utilize I
C(t) and I
A(t) every coefficient ratio is inferred concentration.Below the relational expression of simple declaration formula 9 is false for solution C.
With reference to the resulting electric current I of C solution among the figure 1
CRelation with time t is expressed as by regression equation:
I
C(t)＝5×10
-7t
5-8×10
-5t
4+3.7×10
-3t
3-0.072t
2+0.2031t+57.871
(10)
Because of the coefficient of its high power item is all very little, can ignore equally, therefore equation further is reduced to
I
C(t)≈0.2031t+57.871 (11)
Calculate the coefficient ratio of the equation (formula 6 and formula 11) of solution A and solution C this moment more respectively, obtain
α
c∶α
A＝57.871∶110.14≈0.53；
β
c∶β
A＝0.2031∶(-1.5637)≈(-0.13)；
Because the solute concentration of solution C, A is than 0.01: 0.025=0.4, above-mentioned coefficient value of trying to achieve and 0.4 it doesn't matter, that is:
In summary, under current experiment condition, if certain solution auxiliary salt percentage by weight is 0.02%～0.03% o'clock, the coefficient ratio of the relational expression of its electric current and time and index solution, will equate with the auxiliary salt concentration of index solution with this certain solution, promptly shown in the 9th formula:
Simultaneously, but electrophoretic deposition goes out best cathode base in this scope, is defined as to be fit to electrophoresis concentration.And if the auxiliary salt percentage by weight, does not then have the relation of the 13rd, 14 formulas for reducing to 0.01% when following.
Therefore, the conclusion of the 13rd, 14 formulas can be used as the reference of the concentration of adjusting electrophoresis liquid carbon nano-tube and auxiliary salt.Suppose to have an auxiliary salt percentage by weight between 0.02%～0.03% solution F to be measured, then can utilize the time t and the electric current I at electrophoresis process initial stage
FData computation go out a linear equation, utilize the 13rd, 14 formulas again, then can push away the auxiliary salt ion concentration of this solution F.When
With
Differ 5% when above, represent then that solute concentration is reduced to be fit to outside the concentration, need this moment try to achieve concentration, and replenished by the 13rd formula.
Therefore further, the data drawing list of this current value and electrophoresis time has repeatability, can utilize this graphic data to judge, so that auxiliary salt and carbon nano-tube are supplemented to quantitatively, thereby electrophoretic deposition is deposited applicable to production.The present invention is the chart according to this time and electric current, push away to such an extent that whether the auxiliary salt of current electrophoresis liquid and carbon nano-tube concentration still are fit to, and judge current electrophoresis liquid solute concentration, and need the solute amount of replenishing again, to control this electrophoresis processing procedure, obtain best carbon nano-tube deposition effect.
Below with reference to the embodiment of reality, the experimental data of operation steps and gained is described in detail in detail, and cooperates chart, the present invention further is described in detail in detail.
Solution A is through repeatedly obtaining solution D behind the electrophoresis, and the electric current of solution A and solution D and time corresponding tables are as shown in Figure 3 simultaneously.The electric current of solution D and timing equation are:
I
D(t)＝2×10
-7t
5-2×10
-5t
4+0.0011t
3-0.0216t
2-0.1809t+73.086≈-0.1809t+73.086
Wherein, once the coefficient ratio 8.64 of a coefficient ratio 1.51 and constant term differs 82%, shown in the following calculating, so infer that this solute percentage by weight is own through reducing to below 0.02%, needs to replenish new auxiliary salt and carbon nanotube ionic again.
Then, need to infer the solute concentration of D solution, its account form is as follows.By the 13rd formula as can be known:
Push away to such an extent that the auxiliary salt ion weight number percent in this solution is 0.0166% thus,, need in solution D, to replenish again auxiliary salt 0.0084%, and carbon nano-tube 0.0042%, become the electrophoresis liquid E after the compensation for again this solution being brought up to the concentration of index solution.
Then, in order to ensure touch the mark the really concentration standard of solution of compensation solution E, can be by the electric current and the time relation formula I of solution E
E(t) judge:
I
E(t)＝-4×10
-7t
5+6×10
-5t
4-0.0037t
3+0.1046t
2-1.588t+110.36≈-1.588t+110.36
Wherein, the coefficient ratio of constant term is calculated as follows with coefficient ratio once, because its value is the concentration standard that reaches index solution all near 1 so can rationally infer this solution E.
The constant term coefficient ratio:
Coefficient ratio once:
In other words, owing to try to achieve
With
Difference is too big, though can carry out electrophoresis again, but need bigger voltage or longer time or electrophoresis more frequently, can satisfy required deposition effect, the inventor adds the carbon nano-tube and the auxiliary salt of certainty ratio in D solution in view of the above, so that it is similar to standard solution, and carries out electrophoretic deposition next time, the data that obtains is shown in Fig. 3 and linear data
With
Error is in 5%, and the electrophoretic deposition effect satisfies this sample requirement.
Sum up, the present invention utilizes electrophoresis process, under the stationary electric field operator scheme, with the electric current of two interpolars and time with polynomial repressentation; In other words, electric current I is expressed as the function of time t, i.e. I=I (t).And by coefficient ratio judgement electrophoretic liquid concentration.Below will cooperate explanatory note and process flow diagram that method of the present invention further is described in detail in detail.
Fig. 5 is a process flow diagram of the present invention.As shown in Figure 5, at first need to prepare the index electrophoresis liquid, and set deposition condition, shown in step 40～42.But this index electrophoresis liquid is the solution that electrophoretic deposition goes out the best cathodes substrate, and in the present invention, the magnesium nitrate percentage by weight of this index solution is 0.025%, and the carbon nano-tube percentage by weight is 0.0125%, and the two weight ratio is 2.The present invention simultaneously carries out electrophoresis under stationary electric field, electric field is 10 volts/millimeter; In addition, duty cycle setting is 1/5 (on/total), and electric voltage frequency is got 250Hz.Step 44 promptly under above-mentioned deposition condition, is carried out electrophoresis to index solution.Obtain electrophoretic current in the unit interval at initial stage and the corresponding data of time simultaneously, and by the Return Law with the function representation of electric current with the time, promptly set up equation I
i=I
i(t).In a preferred embodiment, this unit interval is 60 seconds, and electric current is to note down once per 5 seconds simultaneously.
Then, this solution is carried out continuous batch of electrophoresis, and similarly in the time interval, set up the function I of batch electrophoresis liquid in same units
b=I
b(t), shown in step 47～48.In step 50, calculate I
b(t) and I
i(t) the once item and the proportionate relationship of constant term are to infer effects of ion concentration service limits.If its constant term differs above critical value with once coefficient ratio, expression auxiliary salt concentration is lower than below the suitable concentration, then shown in step 54, should calculate the auxiliary salt concentration of current solution, and additional carbon nano-tube and auxiliary salt, with near index solution, be beneficial to the carrying out of electrophoresis next time.
Carrying out the electrophoretic deposition of electron emission source cathode base in this manner makes, can be undertaken by continuous batch of electrophoresis, and can predict and understand the variation relation of effects of ion concentration, utilize quantitatively to adjust to be replenished to make it still can satisfy linear relationship, thereby electrophoresis can carry out in proper order.
Claims (10)
1. the electrophoretic liquid concentration of the carbon nano-tube of a cathode of field emission display substrate is judged and control method, and it may further comprise the steps:
(1) adding carbon nano-tube and auxiliary salt prepare the index electrophoresis liquid in solvent, and set deposition condition;
(2) under described deposition condition, described index solution is carried out electrophoresis;
(3) obtain electric current and the corresponding data of time in the unit interval at electrophoresis initial stage;
(4) reometer of step (3) is shown as the function I of time
i(t);
(5) continuous batch of described solution of electrophoresis;
(6) in the unit interval, set up the electric current of described batch of electrophoresis liquid and the function I of time
b(t);
(7) calculate I respectively
b(t) and I
i(t) once ratio and constant term ratio, and described two ratios are compared;
(8), then calculate the auxiliary salt concentration of batch solution, to replenish carbon nano-tube and auxiliary salt if described two ratios differ above critical error.
2. judgement as claimed in claim 1 and control method, wherein said index electrophoresis liquid are suitably to deposit the solution of carbon nano-tube at the two poles of the earth under described deposition condition.
3. judgement as claimed in claim 1 and control method, the auxiliary salt in the wherein said index solution is a magnesium nitrate.
4. judgement as claimed in claim 3 and control method, the percentage by weight of wherein said magnesium nitrate are 0.03%～0.02%, and the percentage by weight of described carbon nano-tube is 0.015%～0.01%.
5. judgement as claimed in claim 1 and control method, the ratio of the percentage by weight of wherein said auxiliary salt and described carbon nano-tube are 2.
6. judgement as claimed in claim 1 and control method, wherein said deposition condition are included in carries out electrophoresis under the stationary electric field.
7. judgement as claimed in claim 6 and control method, wherein said electric field are 10 volts/millimeter.
8. judgement as claimed in claim 6 and control method, wherein said deposition condition comprise that the duty factor of described power supply is 1/5, and electric voltage frequency is 250Hz.
9. judgement as claimed in claim 1 and control method, the wherein said unit interval is 60 seconds, described electric current is to note down once per 5 seconds.
10. judgement as claimed in claim 1 and control method, wherein said critical error are 5%.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102169102A (en) * | 2011-01-13 | 2011-08-31 | 福州大学 | Method for monitoring and analyzing concentration of nano-carbon material electrophoretic deposition liquid |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102169102A (en) * | 2011-01-13 | 2011-08-31 | 福州大学 | Method for monitoring and analyzing concentration of nano-carbon material electrophoretic deposition liquid |
| CN102169102B (en) * | 2011-01-13 | 2014-10-01 | 福州大学 | Method for monitoring and analyzing concentration of nano-carbon material electrophoretic deposition liquid |
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