CN1332371A - Optical-fiber chemical sensor and its detection method and device - Google Patents

Abstract

The invention provides a kind of sensor and detecting method with fast response, high sensitivity, safety and reliability, high selectivity and durability. The sensor used to detect chemical matter with nonpolarity consists of optical fiber core made from high polymer with polarity and outer layer made from at least one high polymer with nonpolarity that can cause polarity action on the detected matter. The sensor used to detect chemical matter with polarity consists of optical fiber core made from high polymer with nonpolarity and outer layer made from at least one high polymer with polarity that can cause polarity action on the detected matter.

Description

Optical-fiber chemical sensor and pick-up unit and detection method

The present invention relates to a kind of optical-fiber chemical sensor and pick-up unit and detection method that detects chemical substance.This kind optical-fiber chemical sensor can be widely used in and detect various organism: such as alcohols, ketone, amine, amino class, aldehydes, ethers, fine class, aromatics, organic acid and halogen-containing organic compound.Also be specially adapted to gas, liquid or their aqueous solution of hydrocarbons such as gasoline, kerosene, diesel oil, aviation kerosene, the detection of organic solution, and qualitative and/or measure certain special component quantitatively from the above potpourri that multiple compound constituted.And can be used for leakage supervision, the concentration detection of rock gas, liquefied petroleum gas (LPG), propane, butane and acetylene, second diluted gas and be far apart monitoring etc.The sensor that the present invention developed also can be used for the detection of inorganic constituents, such as inorganic acids such as HF, HCl, HBr, HI; Again such as CO, CO ₂, CN, NO, NO ₂, HS, SO, SO ₂, etc. harmful gas and O ₂, N ₂Deng gas, also can be used for the detection of micro-moisture etc.

Be widely used in family now, industry, environmental monitoring, the sensor of the chemical substance in the various fields such as health care is mainly semi-conductor type and solid electrolyte type (being electric driving).Particularly solid electrolytic sensor can reach the requirement of only selecting certain composition because see ion wherein theoretically, but when ion and ambient gas formation slaine, will react with multiple gases, is difficult to realize high selectance.

As everyone knows, the piped gas that uses and the alarm of liquefied petroleum gas (LPG) are exactly semi-conductor type or solid electrolytic sensor now, its poor selectivity, often wrong report.And, the sensor of these types generally need be heated to 300～400 ℃ even to moving more than 900 ℃, therefore the danger of igniting, igniting is very big, has problems in security.Simultaneously, these electric drive-type sensors, also can't use in the place that electromagnetic field is arranged as alarm line with metallic conductor.

In recent years, the more and more strictness of regulations that controls environment and pollute, the polluter that detects and monitor in water quality and the atmosphere becomes an important problem.The water or flow into the rivers and creeks and harm humans and other biological, plant such as the various organic flux that leak from hold-up vessel, the waste water at workshop etc. permeate the ground.But, but do not have effective way to remove to carry out tracing and monitoring to above-mentioned some chemical substance at present.For example, the leakage alarm of piped gas that uses now and liquefied petroleum gas (LPG) is because principle and constructional problem are difficult to be used in various organism and the inorganicss that leak in the underground water of supervision.

Recently, Ri Tekaiping 10-120099 communique proposes to inject solvent in the interlayer of the storage tank with double-layer structural, regularly extracts out then, checks the method that wherein whether contains gasoline.This method does not have problems in security, but can't often monitor, and trivial operations.Method is similar therewith, and Ri Tekaiping 10-293057 communique, Ri Tekaiping 08-327491 communique then are to leak with checking that liquid level detects gasoline in the interlayer.But the gasoline leakage does not reach certain liquid level and just can't find, and the danger of failing to report is arranged.

More than the pick-up unit costliness of these methods, and can't be used for the storage tank of individual layer.

For preventing that automobile fuel filler from makeing mistakes, exploitation has oil and plants the nozzle of recognition function and become more and more important.Ri Tekaiping 10-024997 communique, Ri Tekaiping 09-315498 communique are opened the method for showing and are to use semi-conductor type or solid electrolyte type gas sensor to constitute the nozzle that identification oil is planted.But, under the not volatile low temperature of fuel oil, can't work because of very strong temperature dependency is arranged.And in a single day gas be adsorbed onto and just be difficult on the sensor come off, so return-to-zero needs for a long time.Particularly just at all can not return-to-zero after being flooded by liquid.Also there is the danger of igniting, igniting simultaneously.And owing to need complicated peripheral supporting design so price is also too high.

Because the generation of the methane gas under the mine often causes the well-shoot accident, cause casualties and serious property loss.In order to prevent the generation of this class accident, the fire damp alarm is imported into.But owing to what use is semiconductor-type or solid electrolyte formula sensor, because of absorption down-hole coal dust, and reasons such as aqueous vapor, its life-span is very short, and wrong report is many.In addition, because need be anti-riot, so cost is very high.

Drive to cause often major traffic accidents because of drinking.Although semiconductor-type or electrolyte type alcohol detector etc. are used to check whether the driver drinks, because reaction is slow, sensitivity is low, and the return-to-zero time is long, so can not produce a desired effect.

In the workshop of most use organic chemistry solvents, owing to a large amount of evaporations of solvent and toxic gas such as CO, CN, SO, the SO that in making the product process, is produced ₂, NO, NO ₂, the health that seriously endangers people such as HS.The institute that a kind of small-sized chemical substance monitor easy to carry, highly sensitive, easy-operating becomes people asks.

In recent years, relevant do not ignite, the research of sudden and violent fried dangerous fiber optic sensor is also a lot.Mainly be refraction angle or the rear reflection light that detects the output light cause by the variation of total reflection condition on the principle, and the variation of backscattering light detect.Such as Ri Tekaiping 03-502610 communique and U.S. Pat P.4846548.Owing to detect the problem on principle and the sensor arrangement, even when the gas of high concentration etc. detected, the variable quantity at the refraction angle of its output light is minimum, so be easy to be subjected to clutter to influence, sensitivity is not high.And, measure small angle and change and not only need expensive equipment, need accurate the adjustment during installation, and complicated operation, therefore do not have a practicality.Similarly patent also has: U.S. Pat P.5098659, USP.4913519; Europe patent EP.0601816A2, EP.0550424A2 etc.

And for example U.S. Pat P.4929049 open the technology of showing be with the migration metal be coated on the outside surface of silica fibre, when measured matter and metal are had an effect, the sensor covering with its around solvent between will produce relative change of refractive, thereby achieve the goal by testing catoptrical variation.But this technology is the cost height not only, and sensitivity is low, and is difficult for using.

It is to achieve the goal by testing catoptrical change in color that European patent EP 0621474A1 opens the technology of showing.Must use pigment because of this kind principle and improve its sensitivity, go up inconvenience so not only use, and because of the pigment deterioration, the permanance of sensor be very poor.

In addition, U.S. Pat P.5817727, Ri Tekaiping 09-329553 and Ri Tekaiping 10-104163 communique are opened the method for showing and are, the superpolymer film forming is shone at a certain angle with laser behind glass or prism surface, and the subtle change of the reflection angle when utilizing gasoline to have or not detects.But because the variation of reflection angle is very little, so the concentration range that can detect is limited, and need high-precision fine setting when mounted, use inconvenience, this device price is also very high simultaneously.

Thereby someone uses purpose (popular edition sensor technology, the 416th page of realizing fire alarm with light transmitting fiber at motion as temperature sensor; Science and technology Engineering stock Co., Ltd of Fuji, in October, 1999 distribution; The Off ジ テ of Co., Ltd. Network ノ シ ス テ system).But, after fire takes place, treat temperature rise to can perception degree the time, too late.Therefore can be very important to getting angry the exploitation of sensor of rapid reaction.

The society that is developed as that therefore can satisfy the practical optical-fiber chemical sensor that requires asks.Optical-fiber chemical sensor that can be practical must satisfy following condition under the prerequisite: response time short (such as Millisecond) cheaply; Highly sensitive (such as number ppm level); Repeatability is good, and reliable in action is safe; Permanance and weatherability are strong, are convenient to produce in batches; And easy to use, applied range etc.

Therefore the inventor will develop the sensing probe that can satisfy above-mentioned condition and be considered as finishing important topic of the present invention.For this reason, the inventor mainly is devoted to have solved following problem: 1. will the sensitive time shorten to realistic scale; Can access enough big (being far longer than noise) change amount signal when 2. detecting target substance; 3. the permanance that has realistic scale; 4. has high selectance; 5. has good repeatability; 6. manufacture craft is suitable for a large amount of productions.

Though for overcoming solid electrolyte and semiconductor-type sensor is that defective, the present invention of electric drive-type sensor adopted light transmitting fiber formula sensor, but do not prolong the light total reflection principle that fibre optic chemical sensor adopted (for example aforesaid Ri Tekaiping 03-502610 communique of use-case, P.4846548, U.S. Pat waits), rear light reflection principle (for example U.S. Pat P.4929049, European patent EP 0621474A1 etc.), and rear light scattering principle (lightwave technology, the LT-1 volume, the 3rd phase, the 498th to 509 page; Journal of Lightwave Technology, Vol.LT-1, No.3), loss ripple principle (Europe patent EP.0550424A2 for example, P.5098659, U.S. Pat waits) etc., low because the sensor that these technology provided exists sensitivity, the cost height, shortcomings such as inconvenience use all can not satisfy above-mentioned requirements.The inventor but be conceived to the light wave propagation characteristic be subjected to medium dielectric coefficient influence this point, for example with certain because of with tested chemical substance generation polar reaction after can cause the superpolymer that its dielectric coefficient changes, oligomer or low molecular material are coated on the outside surface of fibre-optic core and make light transmitting fiber formula sensor as covering, when certain tested chemical substance and this coating generation polarity are done at once mutually, because of the dielectric coefficient of the core of sensor constant, and small relative variation will take place in the dielectric coefficient of covering, can make transmission light quantity generation several times and even the variable quantity more than tens of times, thereby reach the purpose that detects certain chemical substance by sensor core.In general, if when the dielectric coefficient of covering is higher than the dielectric coefficient of core, will be very little by the transmission light quantity of core; When the two relation is opposite, the trend of increase is arranged then by the transmission light quantity of core.

For reaching this purpose, in finishing process of the present invention, pay attention to the research of following three sides:

The first, studied tested chemical substance emphatically and constituted polar reaction and the suffered influence factor of this reaction between the covering of fiber optic sensor: the molecular weight and the vitrifacation transition temperature of the superpolymer of (1) formation clad material; (2) once arrive the D structure of high order; (3) crystallization property; (4) especially the polarity of superpolymer to the reactive influence between the two.This has fundamentally understood fully how to control the selectivity of sensor to chemical substance effectively, and improves the sensitivity of sensor and accelerate answer speed.

The second, constructing variable and the manufacturing conditions of sensor and the relation between sensor performance of sensor studied in attention: (1) constitutes the diameter and the cladding thickness of the fiber-optic core material of sensor; (2) effective length of sensor; (3) temperature and the humidity during sensor production; (4) viscosity of high polymeric solution etc.By selecting rational constructing variable and manufacturing conditions, thereby the permanance of sensor is improved, has also improved the repeatability of sensor simultaneously, and improved its answer speed and sensitivity thereof.The 3rd, the influence that the real dress state of sensor is brought into play sensor performance: the stress when (1) sensor is adorned in fact; (2) connected mode between sensor and luminophor and the photoreceptor etc.

Below further describe the method that solves above-mentioned problem.

In order to solve above problem, the optical-fiber chemical sensor that the present invention developed is by core, form with the covering that is coated on this core outside surface, covering contains a kind of superpolymer that polar reaction can take place easily with analyte at least, oligomer and low molecular material.But core must be superpolymer that does not take place with analyte any reaction etc.Guaranteed after covering and analyte generation polar reaction, to make it to obtain bigger relative dielectric coefficient like this and changed, thereby can bring the output signal of several times and even tens of times to change by the variation of this small dielectric coefficient.Therefore, suitable core and clad material are to finish key of the present invention.

(1) selects suitable core

At first to select the core of polarity right sensors.When generally speaking adopting the single mode mode, can use silica fibre to do core, also can make the core of optical fiber with macromolecular material.When adopting the multimode mode, the stock of optical fiber is a macromolecular material, several superpolymer can also be mixed the back extrusion molding in case of necessity.According to the application target difference, promptly when being purpose, the polarity chemical substance should select nonpolar core for use to detect, in contrast, when being target, should select the polarity core for use with nonpolar chemical material.Close with this point and will do detailed argumentation in the back.In addition, at first must meet following condition as core:

(1) only requires that core has the good transparency to get final product in employed optical source wavelength scope.Because general sensor has only several centimeter length, so even also do not influence the performance of sensor a little with any colors.

(2) core should have the good mechanical characteristic.Since actual when using in the sensor charging apparatus, the inevitably impact that will be come from the outside, and vibration stretches etc., does not therefore have enough mechanical properties, just can't guarantee the operate as normal of sensor.

(3) macromolecular material of core must have sufficiently high glass temperature T _g, so that good thermotolerance and stability are arranged.Usually, the T of core _gShould be advisable for high 20～300 ℃ than serviceability temperature.

(4) superpolymer as core must have enough big molecular weight, this not only is related to the mechanical property of sensor, main is the variation that can avoid bringing because of variation of temperature its volume, perhaps this variation can be controlled to minimum, with the reliability that guarantees sensor etc. in general, its molecular weight is with greater than being ideal more than 100,000.

(5) have good physics, chemical stability.Should guarantee that any interaction does not take place for core and analyte, more can not react, with the stability and the reliability of the performance that guarantees sensor with other chemical substance.

(6) last point is exactly the polarity selection problem of core.For example related relevant sensor during at carbon compound among the present invention interacts for making core discord analyte, should use to have polar group, for example SiO, SiO ₂, SO, SO ₂, CN, CO, COO, OH, NO, NO ₂, NR ₁R ₂Deng.The R here ₁, R ₂Can be identical also can be inequality, its formation can be H, alkyl, thiazolinyl, aromatic radical etc.Polar group also can be the superpolymer that contains F, Cl, Br, I.For preventing that unnecessary reaction from taking place, the selection of polar group must be very prudent.

In addition, though polar group also can be in symmetric position, polarity will be cancelled each other, so preferably avoid.

Certainly, it not is not on your life that core and analyte take place to interact, because like this, will bring certain difficulty to the prediction sensing characteristics, because of being difficult to predict the core of sensor and the relative variation of the dielectric coefficient between covering like this.Therefore should avoid as far as possible.

Employed following superpolymer all can satisfy above-mentioned six conditions to core in the experimental example of the nonpolar chemical material of detection for example of the present invention.

Acrylic polymer such as polyacrylic acid, polypropylene hydrogen are fine, polyacrylamide, polymethylacrylic acid, etc. acrylic polymer, poly-N carbazole ethene, polychlorostyrene butylene, polyvinyl dichloride, polypropyleneoxide, poly-3,3, olefines superpolymer such as 3 trifluoro propenes, aldehydes superpolymer such as vinyl superpolymer such as polyvinyl acetate (PVA), polyvinyl alcohol (PVA), polychlorostyrene vinyl acetate, polystyrene, Polyvinylchloride, polyvinyl fluoride, polyvinyl bromide, Vingon, metacetaldehyde, polyoxymethylene, polyvinyl formal, acid polyethylene butyral.

In addition, following superpolymer also can be used to detect the core of the sensor of polarity chemical substance separately, perhaps with the mixed detection that is used in nonpolar chemical material of above-mentioned superpolymer.These superpolymer are: polycarbonate, polymethyl acrylate, polymethylacrylic acid Buddha's warrior attendant ester, polymethylmethacrylate, polymethacrylate, superpolymer such as polyamide-based superpolymer such as nylon 3, nylon 4, nylon 6, nylon 6,6 and polyacrolein.

Close with selecting for use of core and will further be explained by example below.

(2) select suitable clad material

Because after the core of sensor is determined, its selectivity to chemical substance, and induction speed, sensitivity is determined by clad material basically, is can not design desirable sensor so only select suitable core.On this meaning, it is more even more important than selecting core to select clad material.When selecting clad material, mainly note following some.

(1) select suitable superpolymer to make clad material according to the compatibility between covering and tested chemical substance

Clad material depends on to the selectivity of measured matter whether both polarity is identical, and this has also fundamentally determined the having or not of compatibility between the two.Usually get on very well, if the polarity of the two is identical, its compatibility is all right, that is to say that clad material is all right to the selectivity of measured matter.Otherwise it is then different.For example: be detection of hydrocarbon, improve Selectivity of Sensor, prevent wrong report, clad material must have very strong compatibility with carbon compound.For example non-polar polymer is as the clad material ground words of sensor for example to select apolar substance, and sensor just has good compatibility to nonpolar carbon compound.When clad material runs into carbon compound, because the two polarity is identical or close, the low molecule of hydrocarbon will be allowed to diffuse into covering, and then physically will be adsorbed on the superpolymer like this.Sometimes this adsorption phenomena may not take place yet, and only has diffusion process to take place.But the result will cause the variation of the dielectric coefficient of clad material.Like this, because the dielectric coefficient of the core of sensor is constant, the variation of relative amount will take place in the dielectric coefficient of covering relatively with core, although the relative variation of the dielectric coefficient of the two is minimum, the transmission light quantity be changed a lot.The several times that this variable quantity can reach dielectric coefficient before changing and even tens of times.This is in the past electric drive-type and any optical profile type, optical fiber sensor can not compare.

In general, in order to survey carbon compound, the superpolymer that only contains carbon element and protium is exactly the desirable clad material of a class.And such superpolymer can not react with other polar materials easily owing to there is not active function groups, so highly beneficial to the stability and the resistance to chemical reagents that guarantee sensor yet.Below cited superpolymer, all can be used as the main material of the covering of desirable carbon compound sensor:

Molecular weight is 400, tygon more than 000, polybutylene, poly-n-butene, poly-cyclopentane, polyisobutylene, poly-cyclopentyl ethene, molecular weight are 800, poly-cis-isoprene more than 000, molecular weight are 400, poly-trans isoprene more than 000, poly-(1,2 butadiene), superpolymer such as poly-(1,3 butadiene), poly-cyclohexyl ethene, poly-dibutyl itaconate.

Here emphasize to use the superpolymer of high molecular to be not restriction and to get rid of and use low-molecular-weight superpolymer, and other low molecular compounds.

Certainly, the multipolymer that is obtained by the monomer copolymerizable of above superpolymer or the blend of two or more superpolymer also can use.

For regulating the polarity of clad material, above-mentioned superpolymer except can with polysiloxane, outside the blend of epoxy superpolymer, polyvinyl-fluoride, the Kynoar class, poly-fluorine propylene class, poly-fluorine butylene class, the poly-cyclopentanes of fluoridizing, the poly-cyclohexanes of fluoridizing, poly-fluorate acrylic acid lipid, poly-fluorate acrylic acid third lipid, poly-fluorate acrylic acid fourth lipid, poly-fluorate acrylic acid penta lipid, perfluorinates such as poly-fluorinated methyl acrylics is gathered fluorinated methyl acrylic acid penta lipid, the poly-own lipid of fluorinated methyl acrylic acid or partially fluorinated superpolymer also are usually used in blend.

Simultaneously, vinyl polymer classes such as polyvinyl acetate (PVA), tygon ethylether, tygon butyl ether, tygon amyl ether, tygon hexyl ether, polyacrylate, butyl polyacrylate, polyacrylic acid pentyl ester, the own ester of polyacrylic acid, polymethacrylate, poly-n-butyl methacrylate, polymethylacrylic acid pentyl ester, the own ester of polymethylacrylic acid also are usually used in blend.

And for example, be adapted to detect the sensor that alcohol compound, organic acid compound, lipid and ketone compounds, water etc. contain the stronger functional group's of polarity chemical substance, its clad material preferably contains an above halogen for compound optional from F, Cl, Br, I or contain S and the compound of Si etc.

The superpolymer that can satisfy the desired clad material of this class sensor has: silicon-containing compounds such as dimethyl silicone polymer, PSI.Epoxy polymer etc.Polyvinyl-fluoride, Kynoar class, poly-fluorine propylene class, poly-fluorine butylene class, poly-cyclopentanes, poly-perfluorinate such as cyclohexanes, poly-fluoroacrylate, poly-fluorinated acrylamide propyl propionate class, poly-fluorinated acrylamide acid butyl ester class, poly-fluorate acrylic acid pentyl ester class, the poly-own ester class of fluorate acrylic acid, poly-fluorinated methyl esters of acrylic acid, poly-fluorinated methyl acrylic acid pentyl ester class, poly-fluorinated methyl Hexyl 2-propenoate class or the partially fluorinated superpolymer etc. fluoridized fluoridized.

In addition, polyvinyl acetate (PVA), tygon ethylether, tygon butyl ether, tygon amyl ether, tygon hexyl ether, ethyl cellulose, cellulose acetate, polyisobutyl methacrylate, polyacrylate, butyl polyacrylate, polyacrylic acid pentyl ester, the own ester of polyacrylic acid, polymethacrylate, poly-n-butyl methacrylate, polymethylacrylic acid pentyl ester, the own ester of polymethylacrylic acid, and polyvinyl alcohol (PVA), polyacrylic acid etc. also can use with above-mentioned superpolymer blend.

(2) for to make gas, liquid must select the low superpolymer of glass temperature by being spread in covering easily.

The characteristic of the sensor that the present invention developed is determined by gas, liquid seeing through in the superpolymer covering, diffusion, solubility behavior.When glass temperature was following, superpolymer was glassy, was rubber-like when glass temperature is above, and the characteristic that sees through of gas has very big difference.At rubbery state, seeing through of gas is dissolving-diffused, when glassy state, the diffusion motion of gas in high-polymer membrane partly meets the Henry rule, part meets the Lang Gemiuer rule, be double absorbent-type, be stressed, the influence of temperature, concentration is very big, be difficult to use as the clad material of sensor.Such as, DEFORMATION FOR GLASSY POLYMER not only is difficult to find its sensing characteristics at normal temperatures and pressures, even under suitable temperature, pressure, find its sensing characteristics, also must carry out complicated temperature compensation, the seeing through of target substance, diffusion, dissolving simultaneously all varies with temperature, and sensitive time, output signal strength also can change thereupon.So DEFORMATION FOR GLASSY POLYMER is difficult to obtain desirable sensing characteristics when using as clad material separately.

According to actual serviceability temperature should select glass temperature-150 ℃ to the superpolymer between (serviceability temperature-40) ℃ as clad material.This is because use such superpolymer as clad material, and gas/liquid sees through that characteristic is not stressed, temperature, concentration affects, is convenient to use as sensor.Find by lot of experiment results:

1. the clad material of sensor is as selecting the low superpolymer of glass temperature for use, solubility factor when using more than glass temperature in the film and coefficient of diffusion are constant, transmission coefficient is a constant or relevant with pressure a little, but the free energy of diffusion is a constant, so even changes in environmental conditions also can obtain similar detection characteristics.

When 2. using below the glass temperature of clad material, solubility factor, coefficient of diffusion, diffusion free energy are all relevant with concentration, this also provides means for the concentration of detected gas.

In sum, must be according to application target, be qualitative detection or detection by quantitative, the serviceability temperature scope selects to have the clad material of suitable glass temperature.But glass temperature is low excessively, when being liquid during normal temperature, because of inconvenience is used, must and the high superpolymer blend of other glass temperatures or the single amount body copolymerization of the two used.In general, the glass temperature of clad material at-150 ℃ to all obtaining satisfied result between (SC service ceiling temperature-40) ℃.Because in most cases, so sensor is between-150 ℃ to 0 ℃ using optimal glass temperature more than the room temperature.For example, employed Kynoar reaches the glass temperature of poly-rare class superpolymer all below-20 degree in the part experimental example of the present invention.

(3) for making the inner suitable free volume that keeps, must design superpolymer with rational D structure

Superpolymer covering and see through the free energy of molecule and free volume that the interaction of entropy produces, micromolecule seeing through in the superpolymer covering, rate of propagation there is very strong influence, micromolecule is implemented in seeing through in the high-polymer membrane by the chain switch with superpolymer, this needs several sections macromolecular chains to move together, when the space between the superpolymer chain (free volume) increased, rate of propagation also increased thereupon.Because micromolecule seeing through in high-polymer membrane, diffusion and solubility factor and the ratio proportional relation of micromolecular size with the free volume of superpolymer, thus the free volume of high-polymer membrane also be the polymers decision it to micromolecular optionally key factor.Therefore,, obtain desirable answer speed and selectance, be necessary the free volume of the high-polymer membrane of controlling packet layer material for realizing detection to the specific objective material.

From the D structure of superpolymer, desirable clad material should be noncrystalline unformed superpolymer.Because the strand of crystalline high polymer is arranged in order, the interaction of interchain is strong, and glass temperature height, strand are difficult for moving, to micromolecularly see through, diffusion is unfavorable, and material is very crisp, mechanical characteristic and permanance also have problem.For obtaining the amorphism superpolymer, can take two following ways.The first, import long side chain, improve asymmetry.Side chain is methyl, ethyl, the such alkyl of butyl preferably.Generally with the increase of side chain charcoal atomicity and branch chain number, the interaction of main chain weakens, and free volume increases, and glass temperature reduces.The second, obtain the no regularity macromolecule by selecting suitable polymerization.Initiator of polyreaction, polymerization temperature, pressure, time, monomer concentration, catalyzer etc. all must careful selection.

Certainly free volume is not to be the bigger the better yet.Must control suitable free volume according to the size of analyte, this can realize by crosslinked and importing polar group.Crosslinkedly also can when filming, carry out.Often the crosslinking chemical that uses comprises that glycol such as aldehyde, dialdehyde, urea and derivant, ethylene glycol, dicarboxylic acid, amine and diisocyanate, diepoxides, two ethene etc. can cause the compound that contracts and react.Then often use following compounds from the cross-linking reaction of monomer: diallyl compounds such as divinyl compound such as divinylbenzene, hexadiene, hexatriene, divinyl ether, divinylsulfone etc., dially phthalate, diallyl methyl alcohol.

Can use the polar group that contains S, Si, O, N element, for example SiO, SiO when importing the base group ₂, SO, SO ₂, CN, CO, NO, NO ₂, NR ₁R ₂Here R ₁With R ₂Can be identical or inequality, its composition can be H, alkyl, allyl, aryl etc.Polar group also can be F, Cl, Br, I etc.

Here special needs to be pointed out is that by cross-linking reaction, the size of may command free volume not only, and can obtain net high-polymer can be not dissolved, also difficult drop-off thereby improved the permanance of sensor.

In addition, the free volume of regulating covering also can be by two or more superpolymer, and oligomer or low molecule mix mutually and reach.For example the superpolymer of low Tgs such as ethyl cellulose, cellulose acetate, polyisobutyl methacrylate, dimethyl silicone polymer, PSI, epoxy polymer is just very useful.Glass temperature such as dimethyl silicone polymer is-130 ℃, and is amorphism, and intermolecular gap is very big, and the sectional area of strand direction is 1.7 times of hydrocarbon.When using the less superpolymer of free volume, can regulate its free volume by mixing an amount of type siloxane superpolymer.When making core with polymethylmethacrylate, clad material is only with density greatly during 0.96 polyisobutylene, so just react because of gas is difficult to the diffusion tens of branch kinds of needs of entering, do not have practicality.Mix certain polysiloxane or epoxy polymer shown in the experimental example among the present invention, significantly shorten response time owing to the increase of free volume, the diesel oil that molecular volume is big, kerosene also pass through easily, have obtained the good detection characteristic.

(4) be permanance that obtains sensor and the balance of responding to speed, superpolymer must have suitable molecular weight

Usually get on very well, the molecular weight of superpolymer is more little, and the systematicness of strand and orientation are low more, and intermolecular interaction is weak more, so induction speed is just fast, but dissolved easily or come off, permanance is not high.For example, molecular weight is coated in the sensor that obtains on the core of polymethylmethacrylate at the polyisoprene below 100,000, when normal hexane is detected, along with the increase that detects number of times, output intensity reduces gradually, illustrates that polyisoprene is gradually by n-hexane dissolution.

Certainly the molecular weight of covering is high more, and its permanance is just high more, but because of its solubleness reduces, is unfavorable for producing.Special solution viscosity is too high when molecular weight is too high, makes very difficulty of homogeneous cladding, and this is not only unfavorable to volume production, and its sensitivity also descends.Experimental result shows, is the induction speed that keeps sensor, permanance and productive balance, and the molecular weight of the superpolymer of clad material should be 200,000～2, between 500,000, and ideal between 300,000～2,000,000.

(3) constructing variable of sensor reasonable in design

Can solve above problem, except the core and clad material of selecting right sensors for use, the structural property parameter that reasonably designs sensor also be crucial.That is to say and selected proper core and clad material, can guarantee after covering and analyte generation polar reaction to obtain the variation of bigger dielectric coefficient, thereby can bring the output signal of several times and even tens of times to change by the variation of this dielectric coefficient.This has fundamentally guaranteed the selectivity of sensor to chemical seed.Change but seek out very responsive signal, and durable sensor, the structural parameters of core and covering is very important.By a large amount of experiments, the inventor has found out the right sensors constructing variable.

(1) the thin more answer speed of covering is high more, but crosses when thin too smallly because of the variation of output signals amount, and sensitivity is not high.If but the packaging material layer is blocked up, response time will be long, even the danger that has detection not go out.The general thick needs that just can satisfy sensitivity between 0.1 μ m～0.5 μ m of covering, only thickness is 0.2 μ m～0.3 μ m.This has following benefit:

1) is beneficial to the balance that obtains induction speed and sensitivity.

2) be beneficial to the enough permanance of acquisition.

3) can help a large amount of productions by flowing Yan, steaming or the simple film forming of rubbing method.

The manufacturing process of covering comprises following step: after 1. choosing suitable clad material, with solvent it is dissolved.2. add crosslinking chemical as required.3. measure and adjust solution viscosity.4. solution is controlled under the suitable temperature.5. after solution being coated onto the core surface, dry under the fixed condition.

(2) length of sensor is long more, and the variation of output signals amount is big more, and sensitivity is high more, but is used for considering from being beneficial to real dress and reducing manufacturing cost, must be length control within limits.A large amount of experimental results show that, at the gas or the liquid of most of tested chemical substances, the appropriate length of sensor is ideal between 5cm to 10cm.This has following benefit:

1) can enough rational expenses reach necessary sensitivity and the sensitive time.

2) keeping the high performance while, can realize the miniaturization of sensor, be convenient to use.

3), realize that a kind of many purposes of sensor are used, so that a large amount of production by selecting suitable material.

Certainly, length discussed here neither be absolute.Such as the leakage for the monitoring natural gas line, sensor need be along the pipeline setting, and length can reach tens of kilometers.

(3) diameter of core is thin more, and sensitivity is high more.This be because light when same angle is injected, the thin reflected light of diameter often, the variation of output signals amount is also just big more like this.But fibre-optic intensity reduces.When generally detecting with many optical modes mode, the core diameter gets final product at 0.2mm to 2mm, and is especially ideal at 0.5mm to 1.0mm.If sensitivity need reach several ppm to tens of ppm, just must use the single mode core, core diameter at this moment generally should be at number μ m between tens of μ m.

(4) refractive index with core and clad material is controlled in the suitable scope

Between the refringence that experimental results show that the core of sensor and clad material is preferably in 0.005 to 0.025 for well.If it is improper that the refraction folding rate of the two is selected, though when the two dielectric coefficient because of covering with relative variation has taken place after tested chemical substance reacts, its effect can be cancelled to a certain extent.Strictly speaking, the essence of this phenomenon is because the refractive index selection of core and covering is improper, makes the transmission light quantity be in a kind of state of saturation.Under this state of saturation, change a lot because of the dielectric coefficient of covering changes even transmit light quantity, also can't exceed the state of saturation level, promptly be absorbed in the dead angle.Sometimes, though this phenomenon does not influence the selectivity of sensor to chemical substance, will have influence on the sensitivity of sensor.Promptly under the situation of low concentration, can't detect.The experiment proved that: the refringence between core and covering is more satisfactory between 0.005 to 0.025.This has following benefit:

1) can obtain balance between required induction speed and required accuracy of detection.

2) can realize the induction speed of Millisecond.

3) can obtain the sensor of high sensitivity.

4) the material selection is wide, produces easily, has wide range of applications.

In sum, the design of the material of sensor can reduce following step: 1. setting the required sensitive time is speed; 2. predict the core of sensor and the electrification coefficient difference between covering; 3. determine the refringence between core and clad material; 4. select suitable core; 5. select clad material easy and the target substance reaction; 6. for regulating the characteristic of clad material, select the material that mixes mutually with selecteed clad material as required or make two or more monomer copolymerizables.

(5) manufacturing conditions of the suitable covering of control

Can obtain desirable covering, except strict selection and selection rational structure parameter, the manufacturing conditions of covering be also very important.This comprises the following aspects:

(1) temperature this to look the molecular weight of superpolymer, its crystallinity is determined doing after the solution temperature in when coating and the coating

Dry temperature.Purpose is to control the crystal structure of covering, degree of molecular orientation and free volume.

(2) humidity and air quantity are controlled the rate of drying of covering of coating to reach controlling packet by regulating humidity and air quantity

The purpose of the crystal structure of layer.

(3) solution concentration.These factors are directly connected to the crystal structure of covering, degree of molecular orientation and free volume big

Little, therefore must control proper.

(6) adopt real easily packing technique and do one's utmost to eliminate influence from the noise composition of environmental factor

When the real dress of sensor, signal can change (such as from electric wave, undesired signals such as light) with environmental change, and how noise being suppressed to irreducible minimum also is a problem.For the detection characteristic that guarantees sensor not because of the change of environmental factor changes, except having done to make great efforts when the design sensor, the present invention also motion a series of real packing techniques remedy the drawback that when the design sensor, can't overcome.For making sensor can satisfy sensitivity requirement under the different situations, below six kinds of real packing techniques can use for you to choose.

First uses the reference signal sensor.This sensor promptly is made of core, first covering and second covering, and first covering is by constituting with the superpolymer or the low molecular compound of analyte reaction.Second covering then is to be made of the material that the discord analyte reacts.During actual the use, with with the sensor of second covering with do not expose simultaneously and analyte with the sensor of second covering, have the sensor of second covering owing to be not subjected to the influence of measured matter, other noise signals relevant with environmental change can be provided, like this, just can remove Effect of Environmental effectively to make comparison process from the signal of two sensors.Certainly, the core of two sensor units and first covering must be respectively commaterials.

The second, for example can use two sensors 1 and 2, light is gone into from an end-fire of first sensor 1, establishes a reflector element at the other end, makes reflected light can inject an end of 2, takes out signal from 2 the other end at last.If sensor 1 and 2 has same structure and made by same material, the variation of output signals amount will be 2 times during only with a sensor, i.e. sensitivity reaches 2 times.

Certainly, the sensor here can have same structure, be made by same material, also can have different structures, make by different materials.

The 3rd, the optical fiber that will be connected with sensor one end is branched into two in position, and one is used for transmitting, and one is used for received signal.And be provided with reflector element at the other end of sensor.Can be implemented in the same side emission, the received signal of sensor like this.This method is the same with said method, also can obtain sensitivity effect at double.

Reflector element can be the low sheet metals of absorbance such as silver, aluminum, also can be gold-plated, and is silver-plated, aluminizes etc. to plate the substrate of metal.Substrate can be a sheet metal, glass plate, crystal etc.Its shape can be the plane, also can make arbitrary surface.Its plane of incidence can be in a certain angle relatively with reflecting surface, the prism etc. of for example squaring up.

Reflector element both can be separately fixing separately with sensor, also can be fixed on the end of sensor.

When reflector element is fixed, the end face of sensor can be close to, also certain distance can be kept.

Simultaneously, reflector element also can be a certain angle with the sensor end face, and this all decides on actual needs.

The 4th curves cast with sensor.Can enclose into the integral multiple angle of 90 degree, promptly can be 180 degree, 360 degree, 540 degree etc.Can certainly be arbitrarily angled.

Can reach following three purposes by this skill:

When 1) using the very long sensor of length, miniaturization that also can implement device.

2) same length, crooked sensor has bigger variable quantity than linear pattern, and sensitivity is higher.

3) can launch in the same side, received signal.Help real dress, for example the various domestic gas alarms of portable type,

Medical apparatus, nozzle etc.

The 5th, the diameter (comprising covering) with sensor that the fibre diameter of launching light signal is designed is the same, and the fibre diameter of receiving optical signals is equal to or less than the diameter of the core of sensor unit, the light that penetrates from the covering of sensor just can not be received like this, can reduce the ambient light influence, improve sensitivity.

The 6th, the loss of optical signal that produces for the linking place of reducing sensor and optical fiber, and the influence of the vibration that comes from the outside are with luminous and directly be connected on the two ends of sensor respectively by the light photodiode.Do the purpose that not only can reach simultaneously saving optical fiber like this, can also make equipment miniaturization, be convenient to real dress.

Can satisfy detection and the monitoring requirement of all trades and professions by this a series of sensor that effort, the present invention developed to various organic and inorganic chemistry materials.Such as:

1) leakage of refuelling station and refinery storage tank and bottom ponding supervisory system

2) supervisory system of various chemical substances in the water under the river reaches

3) intelligent nozzle is planted identification sensor with oil

4) the oil kind identification sensor and the densimeter of tank wagon and fuel loading system thereof

5) indoor piped gas, liquefied petroleum gas (LPG) leakage warning device

6) the leak supervision system of inflammable gas conveyance conduit

7) the liquid level meter of storage tank and steel cylinder

8) detection of detection of the concentration of organic flux and various harmful gases in the workshop

9) gas monitoring system in the mine

10) monitoring system (fire alarm system etc.) of industry and civilian carbon dioxide packing gas and carbonic oxide gas

11) the concentration of the particular chemicals in solution supervision (such as: halogenide, the hydrogen peroxide concentration mirror is surveyed meter etc.)

12) the medicine equipment biological component sensor used (such as sweating meter, halitosis meter etc.)

13) other industrial and civilian sensors

Compare with the optical fiber sensor that electric drive-type sensor is other types, the optical-fiber chemical sensor that the present invention developed clearly has following characteristics:

(1) simple in structure, with low cost

Use the common plastics or the core of glass optical waveguide fibre, after coating the solution drying, perhaps film directly is bonded in and promptly can be made into sensor on the fibre-optic core, can sensor be connected with proving installation by common optical fiber as required, can certainly directly not be connected with proving installation by light transmitting fiber.This kind sensor is not only very easy to use, also is beneficial to batch process.

(2) answer speed piece

Sensor is at the gas that touches various organic and inorganic chemistry materials, during the mixture of liquid or these chemical substances and other compositions, all at 0.5 second with interior action.Particularly detecting pipeline gas, liquefied petroleum gas (LPG), acetylene, steam and alcohols such as gasoline, ketone, the time of sensor action all below 1 second, has overcome chemical sensor required actuation time of the long disadvantage of other types to their response time of liquid all below 0.1 second during the isopolarity chemical substance.

(3) highly sensitive, the detectable concentration wide ranges

Such sensor can detect from the existence of the various organic and inorganics between number ppm～100v% concentration.Between its output signal strength and the concentration good linear relationship is arranged.

(4) splendid repeatability

To various organic-inorganic chemical substances, this sensor all has splendid duplicate detection characteristic.Particularly when concentration reduces, can on signal of sensor, feed back immediately, therefore can be used in detection by quantitative.

(5) splendid selective power

Even use same sensor also can carry out effective recognition to different chemical substances, this is because sensor can provide different response characteristics to different chemical substances.In addition, use, also can distinguish similar substance with a kind of sensor.For example use with a kind of sensor gasoline, it is exactly a typical example that kerosene, diesel oil can be discerned.

(6) splendid permanance

The material that such sensor is selected, without special chemical treatment, the chemical property torpescence has splendid anti-, alkali resistance, resistance to chemical reagents and weatherability, can guarantee to work steadily in the long term.

(7) good weathering characteristics

Such sensor is not subject to daylight, rainwater, the influence of temperature etc.More be not subjected to electromagnetic interference.Therefore, not used arbitrarily by any condition restriction ground.

(8) action is naturally restored automatically

Such sensor is when running into analyte, and is different with the sensor of other modes, need not heating and waits and action naturally.When analyte disappeared, sensor also restored automatically.

(9) need not anti-riot countermeasure, security is good

(10) driving electric is little etc.

Below come further real attitude of the present invention to be described by some concrete instances.But, scope of authority that the present invention advocated is not subjected to the restriction of these examples.

The test example of example one alcohol gas: the method for making of sensor is as described below: poly-methyl-prop diluted acid (PAC, the T that will contain polarity carboxy CO OH _g=-38 ℃, Mw=500,000) 0.1g is after dissolving, and at 80 ℃, relative humidity is to be applied to non-polar polymethylmethacrylate (PMMA, T at 60% o'clock _g=95 ℃, Mw=960,000) on the coremaking material, after dry 24 hours, system is grown into the 5cm sensor through room temperature (25 degree Celsius).Core diameters is 0.95mm, and cladding thickness is 3 μ m.

Fig. 1 is the synoptic diagram of the assembled unit of this sensor: 1 core; 2 coverings; 3 light sources; 4 light-receiving tubes; 5 shadow shields; 6 sensor protection shells; 7 luminophor gim pegs; 8 photoreceptor gim pegs.Light source (3) can use the light emitting diode (LED) or the LASER Discharge Tube (LD) of any wavelength.Because polymethylmethacrylate has minimum light conduction loss near 567nm, so this experiment has used the green LED of maximum wavelength λ max=570nm as light source, and adopted silicon electric diode (PD) as photoreceptor.

Sensor S is installed in shown in the figure (2) and gets in the test macro.Gas imports light shading type testing tube (10) through Y-pipe (9) by syringe (16).Be connected with same Y-pipe (9), one end the opposing party of shading testing tube (10) and receive on the vacuum pump pressure in order to regulating system by conduit (15).The two ends of sensor S are connected in lead (11) by the connector (12) of special use.Handle by microcomputer (14) again through the AD transducer behind the signal input processing device (13).

Ethanol sample is spent, is modulated in airtight casing in room temperature 25.Alcohol gas through with drying nitrogen towards rare be 800ppm, 400ppm, the sample of three kinds of concentration of 100ppm.Find after tested: definitely export maximal value with concentration of ethanol is linear, required time is 0.8 second when gas is injected into sensor and moves.

The comparison and detection example of example diethanol gas: using the method identical with last example to make length is the sensor of 20cm, then it is curved the ring-type that diameter is 3cm, is connected with optical fiber again.In this case, bigger 1.5 times than example one with the corresponding absolute output maximal value of various concentration, i.e. the sensitivity of the sensor of example two is 1.5 times of example one.

The detection of example three methyl alcohol gases: the sensor of use-case one detects the methanol gas of five kinds of concentration, its result shows, this sensor also has good sensitivity to methyl alcohol, although the absolute maximum output valve of methyl alcohol hangs down 10% approximately than ethanol with regard to same concentration.But it is variant that the two reaches the peaked time, and this points out us to distinguish methyl alcohol and ethanol by the method for curve of output being asked first order derivative.In fact, when concentration was 800ppm, the differential maximal value of methyl alcohol was 0.2 (V/100mS), and the differential maximal value of ethanol is 0.5 (V/100mS), and this is enough to distinguish methyl alcohol and ethanol.

The comparison and detection example of example tetramethyl alcohol gas: as a comparison case, adopted reflective test macro to test here.On the one side of glass, plate one deck silver as reflecting body.This reflecting body is fixed on an end of sensor, and makes it become miter angle with the long axis direction of sensor.Be subjected to the fiber optics maintenance and send fiber optics parallel.For enlarging its light-receiving area, its end is cut into necessary angle.Adopt the resulting absolute maximum output valve of reflection mode to compare and almost do not have difference with the mode of seeing through.This explanation adopts the reflection mode not only can obtain satisfied result, can also be convenient to the peripheral supporting design of sensor simultaneously, reduces cost to reach, and makes the target of whole equipment miniaturization.

The detection of example five water vapor: in order to detect water vapor, the core of sensor has adopted polycarbonate, and selects phenolics (PPhA) to make clad material.After this high polymer material is dissolved in the solution that contains ferric ion, after heat treated complex compound to be formed, is applied to the core surface and makes sensor.Testing result shows: in the scope of relative humidity 0.005% to 100% very high sensitivity is arranged all.And, because of this kind sensor to the equal Fails To Respond of other organism beyond the water, so be a kind of very desirable humidity sensor.

The Comparative Examples that example six water vapor detect: do a contrast experiment for importance and example five that core is selected are described.Adopt the core of polyvinyl alcohol (PVA), and the poly-phenolics of same employing is made clad material as sensor.Under identical conditions, water vapour is tested.The result is reactionless.Its reason is because adopted the polyvinyl alcohol (PVA) of polarity to make core, when sensor runs into water vapour, covering not only, core also with water polarity has taken place answers, consequently the relative variation of the dielectric coefficient between core and covering is difficult to manifest, so its output signal has dominance and changes, or have and small variation and can't reflecting by output signal.

The detection of example seven acetone: because of acetone also is strong polar material, so also adopt Kynoar (PVDF, the T that contains strong polarity element F _g=-38 ℃, Mw=530,000) 0.2g and 0.7g polyisoprene (trans, PIPt, T _g=-68 ℃, Mw=410,000), and behind the polymethylacrylic acid mixed dissolution of 0.1g, in the time of 80 ℃, be applied on the polymethylmethacrylate coremaking material, after 24 hours, make detecting unit through drying at room temperature.The acetone gas sample is tested.The result shows that the acetone gas below the 100ppm is also had very high sensitivity.

The detection of example eight acetone liquid: the sensor of example uses dialdehyde as crosslinking chemical covering to be made crosslinking Treatment before the sensitivity in aqueous solution is tested to acetone in the use.Doing one like this is to come off in order to prevent that covering from dissolving, the 2nd, and in order to improve the selectivity of covering to acetone.With acetone vapor phase ratio, although sensor is slow 0.2 second actuation time, its susceptibility exceeds 20% than gas.

The detection of example nine ammonias: will contain the polyamine 0.6g of polar group and polyphenyl phenol 0.4g and be coated on through dissolving, after mixing to dry behind the non-polar polycarbonate coremaking portion surface and make sensor.To be diluted as 100pmm then, 500ppm, 1,000ppm, 2, the ammonia sample of 000ppm variable concentrations injects testing tube to be tested.The result shows that ammonia is had sensitivity admirably and concentration interdependence.

The detection of example ten CO gas: Vingon (PVDC) 0.7g and polystyrene (PVB) 0.3g dissolved respectively be applied on the polymethylmethacrylate coremaking material after mix the back, after 48 hours, make sensor through drying at room temperature.After tested, be 10ppm to concentration, 50ppm, 100ppm, the CO gas of 500ppm all presents good sensitivity.And good correlativity is arranged with its concentration.

The detection of example 11 carbon dioxide packing gases: the sensor of use-case ten is similarly tested carbon dioxide, and it is to 100ppm, 500ppm, 1,000ppm, 2, the gas of 000ppm is very responsive, and after gas imported, only 0.5 second sensor promptly began action.

Example 12 uses the detection of sensor group to carbon dioxide packing gas: with the clad material solution that the sensor of example ten is used, be coated with the responding layer of growth 3cm along the every interval 1m length of the PMMA coremaking material of long 100m.Then with this sensor group along long 5m, the cabinet wall of the high 3m of wide 4m is behind 5 circles, two ends join with light emitting diode (LED) and light-emitting diode (PD) respectively and constitute after the test macro, again concentration is respectively 200ppm, 400ppm, 600ppm, 800ppm and 1, the carbon dioxide of 000ppm injects respectively, and its response characteristics is tested.Behind the intact sample of every survey, carry out another time experiment again after fully replacing with drying nitrogen in the case.Consequently, the carbon dioxide packing gas of the above concentration of 200ppm is promptly replied.Its reaction time is in 1 second.

The detection of example ten trioxids: the application of the sensor in ten as an example, at first sensor is placed the testing tube that is full of drying nitrogen, after treating that output is stable, again concentration is respectively 200ppm, 400ppm, 600 ppm, 800ppm and 1, the oxygen of 000ppm injects respectively, and its response characteristics is tested.Consequently, the oxygen to the above concentration of 200ppm all has negative replying.This points out us, can use this kind sensor respectively to oxygen by suitably changing the method for test condition, nitrogen and CO gas, and carbon dioxide packing gas detects.

The detection of example 14 Difluoroethanes: with Kynoar 0.2g and polystyrene 0.7g, and the phenolics of 0.1g dissolves the back respectively and mixes, and is applied in the time of 60 ℃ on the polycarbonate coremaking material and makes sensor.After tested, concentration is respectively 100ppm, 500ppm, 1,000ppm, 2, the Difluoroethane aqueous solution of 000ppm has all presented good sensitivity.And there is favorable linearity relevant with the concentration of Difluoroethane.

The detection of example 15 hydrochloric acid: Vingon 0.1g and polystyrene 0.9g dissolved respectively be applied on the polycarbonate coremaking material after mix the back, after drying at room temperature, make sensor unit.After tested, concentration is respectively 100ppm, 500ppm, 1,000ppm, 2, the aqueous hydrochloric acid solution of 000ppm has also presented good sensitivity and concentration correlativity.

The detection of example 16 gasoline gases: with Kynoar and polyisoprene in 1: 3 ratio mixed dissolution after, in the time of 80 ℃, be applied on the polymethylmethacrylate coremaking material, make sensor unit through drying at room temperature after 24 hours.Core diameters is 0.75mm, cladding thickness 5 μ m.

Get and long investigated response characteristic for the sensor of 5cm gasoline vapour.And curve of output has been carried out the single order differential handled., sensor back in the injection of gasoline gas promptly reached differential maximal value 0.45 after having made immediately and having responded to approximately through 1 second.For the return-to-zero characteristic of investigating sensor, wait to export after reaching maximal value, the Y-pipe that soon is connected with vacuum pump rotates to the release position and vacuumizes.Output required time when maximal value drops to baseline value only is 4 seconds.This shows, this sensor not only has good response characteristic and also has good restoration characteristics simultaneously.This is that the sensor of the semiconductor-type that comes of example is beyond one's reach.

Between gasoline concentration 0.1v%～25v%, every increase by 1, during 000ppm, sensor all presented good resolution energy.

The Comparative Examples of example 17 gasoline gas detection: make the detection system of use-case 16, but incident is 1mm with the diameter of optical fiber, and the diameter of optical fiber for receiving light is 0.95mm, measures under similarity condition, the maximum differential value is about 2 times of example 16.In other words, when being 500ppm, gasoline concentration also can obtain good sensitivity.Simultaneously, reach the also cripetura to 0.8 second of peaked time of differential.

The detection of example 18 diesel vapor: polycarbonate (PC, T _g=120 ℃, Mw=380,000) and polyvinyl acetate (PVA) (PVAc, T _g=30 ℃, Mw=350,000) mixed the core that diameter 0.95mm is made in the back extrusion molding by 18.3: 81.7, with polypropylene (T _g=-26 ℃, Mw=650,000) be coated in after the dissolving and obtain sensor on the core after drying.The result that the response characteristics of diesel vapor is investigated is, reaches maximum differential value required time and is about 1.0 seconds, and output reached the maximal value required time about 3 seconds.The maximum differential value is 0.025 (V/100mS).This shows, be 10 times of diesel oil approximately in the differential maximal value of gasoline.

This results suggest we, make the sensor of use-case 16 and example 18 simultaneously, can discern gasoline effectively, three kinds of materials of diesel oil and air, this is enough to satisfy the practical requirement of intelligent nozzle.

The detection of example 19 kerosene liquid: will gather (1,2 butadiene) (PBD, T _g=-95 ℃, Mw=350,000) 0.84g, polyacrylic acid trifluoro methyl esters (PTFEA, Mw=550,000) 0.16g is coated on the core of example 18 and makes sensor after dissolving.In addition, come off for preventing the covering dissolving, with oneself two rare crosslinking Treatment of having done.The result who detects kerosene liquid is, is 0.5 second from kerosene liquid injection back to the time that sensor moves, and reaching differential maximal value required time is 1.5 seconds, and its value is 0.06V/100mS, is 2 times of diesel oil approximately.

Also obtained satisfactory detection result when making the sensor of use-case 18.

The response characteristics of example 20 acetylene gas: polyoxymethylene (POM, the T that will contain polar group _g=28 ℃) make the core of 1mm with extruder.Non-polar polyisoprene, dimethyl siloxane mixed to be coated on by 59: 41 with the multipolymer of diphenyl siloxane make covering on the core.Remove small noise for the Lu,, used two sensors to constitute proving installation here simultaneously to improve the sensitivity of sensor from environmental factor.Second sensor has the first identical covering with first sensor.But this sensor has not the polymeric membrane that reacts with acetylene, promptly so-called second covering.This layer is by polymethylmethacrylate and poly-phthalic acid resin (T _g=100 ℃, Mw=380,000) by behind 6: 4 mixed dissolutions, film forming is made on first covering.Two signal of sensor are received by two silicon photoelectric diodes respectively.

With drying nitrogen the acetylene gas accent is interpreted as 1,000ppm, 500ppm, 100ppm, and four kinds of concentration of 50ppm.Test result shows that this kind sensor has good sensitivity and concentration interdependence to acetylene gas.

The detection (1) of example 21 butane gas: with Polyvinylchloride (T _g=105 ℃) and polyvinyl acetate (PVA) to mix extrusion molding by 32: 68 be the core of diameter 1mm, sensor is made in the clad material coating of use-case 19, making the detection system of use-case one is 1 to concentration, 000ppm, 500ppm, 100ppm, the butane gas of 50ppm is tested.The result shows that this kind sensor has good sensitivity and concentration interdependence to butane gas.Its reaction time is all in 1 second.

The detection of example 20 divinyl gases: with tygon fine (PAN, T _g=120 ℃) and polyvinyl acetate (PVA) make sensor with the polyisobutylene coating after mixing the core that extrusion molding is diameter 1mm by 49.5: 50.5.Concentration is respectively 1,000ppm, 500ppm, 100ppm, the ethylene vapor of 50ppm is tested in the injecting tube respectively.Test result shows that this kind sensor also has good sensitivity to the ethylene gas below the 50ppm.Its reaction time is all in 1 second.

The detection of example 23 n-decane gases: the sensor that uses two examples 22, by the aluminium sheet reflection, make incident light continuously by two sensors, the testing result that aligns own decane steam is, reach differential maximal value required time and be about 1 second, the maximum differential value is 0.5 (V/100mS).

The detection (1) of example 24 benzene vapors: polyisobutylene (T _g=-76 ℃, Mw=420,000) 0.87g, be coated in after dimethyl silicone polymer (n=1.37) the 0.13g dissolving on the core of polycarbonate potpourri of example 20 and make sensor, be assembled in the detection system then, the benzene gas of 100ppm is injected through syringe, and output signal began to rise from baseline position after 0.5 second thereupon.The maximum differential value has reached 0.2 (V/100mS).This illustrates this sensor, even there are the ground words in the benzene of 10ppm concentration, also might detect.

The detection (2) of example 20 pentaphene steams: as the contrast of example 24, at first, with the example 24 the same sensing parts that on the polycarbonate core, make 5cm, at the same optical fiber of the plane of optical fiber side being cut out 1cm from its 10cm place and another root at the place, plane with the bonding sensor of making of bonding agent.The result that the method for use-case 24 is detected shows that output bare maximum ratio 24 has increased one times.Steam has only promptly begun action through 0.5 second sensor after injecting.

The detection (1) of example 26 liquefied petroleum gas (LPG) (propane) gas: with PSI (PMPhS, Mw=430,000) 0.58g, Kynoar 0.42g dissolving is coated on the core of PMMA and makes sensor after drying.Pack in the test macro, with 5,000ppm, 4,000ppm, 3,000ppm and 2,000ppm, 1, the liquefied petroleum gas (LPG) of 000ppm (propane) gas injects respectively, and its output characteristics is tested.The result shows that the output maximal value is directly proportional with the concentration of propane, and being injected into sensor action required time from gas is 0.5 second, and reaching the peaked time of output is 6 seconds.

The detection (2) of example 27 liquefied petroleum gas (LPG) (propane) gas: with PSI 0.566g, polyacrylic acid fluoroethyl ester (PFMMA, Mw=510,000) 0.434g is coated in after the dissolving on the core of polymethylmethacrylate and makes sensor after drying.The result who detects propane is, it is 5 seconds that sensor reaches the peaked time of output, and it is definitely exported maximal value and exceeds 25% than example 26.

The detection (1) of example 28 piped gases: making the sensor (length 10cm) of use-case 27 is respectively 8 to 4 kinds of concentration, 000ppm, and 4,000ppm, 2,000ppm, 1, the piped gas of 000ppm detects.Absolute output maximal value is directly proportional with the concentration value of gas, and reaches the peaked time all in 5 seconds.

The detection (2) of example 29 piped gases: for improving the sensitivity of sensor to pipeline gas, light emitting diode and light-emitting diode directly are fixed on the two ends of employed sensor in the example 28 with the loss of minimizing light and the influence of noise.Result to piped gas is: sensor action required time shortens to 1 second, reaches the peaked time of absolute output also in the cripetura to 5 second.Concentration is 1, and the absolute output maximal value during 000ppm is 1.5 times of example 28.

The above example of introducing only is the sub-fraction of experiment that the inventor does.For example, in fact use (one) in the detailed Description Of The Invention cited core and (two) cited experimental result that clad material carried out to show, all at the gas of chemical substance, liquid and solution have shown good result, describe in detail no longer one by one here.

What also need additional disclosure here is, in view of experiment is not adopted best signal processing circuit with proving installation, for example limited except that performance because of the noise Lu, as if the concentration range that can detect be partial to high concentration, but, if this is done some words with improvement, the effective minimum sensitivity of such sensor can be brought up to several ppm.

Now with employed core of the sensor among the part embodiment among the present invention and clad material, reach the least concentration (C:ppm) that these sensors can detect, differentiate energy (I:ppm), and sensor (t: second) actuation time, the maximum single order differential value (D:V/100mS) of induction curve is summarized as follows: object material core material clad material C I t D piped gas PMMA PMPhS/PFMMA 2,000 500 1.2 0.15 liquefied gas PMMA PMPhS/PFMMA 1,000 500 1.0 0.18 gasoline PVC PtP/PVDF, 1,000 500 0.1 0.12 kerosene PAN/PVAC PBD/PTFEA 500 500 0.1 0.06 diesel oil PC PIPt/PVDF, 500 500 0.2 0.01 acetylene POM PiP/PMPhS 50 50 1.0 0.12 normal hexane PAN/PVAC PBD/PTFEA, 500 500 0.1 0.5 ethanol PMMA PAC or PPhA 100 50 0 0.1 methyl alcohol PMMA PAC or PPhA 100 50 0 0.1 water vapour PC PPhA 50 50 0.2 0.05 acetone PMMA PVDF/PIPt 100 50 0.1 0.12 carbon monoxide PMMA PVDC/PVB 10 10 0.5 0.03 carbon dioxide PMMA PVDC/PVB 10 10 0.5 0.05

Can be clear that from above example, the present invention is by selecting suitable core and clad material and adopting a series of effort such as rational real packing technique, successfully with in the cripetura to 1 detection time second, developed can detect from zero ppm to 100% concentration level, its resolution can reach tens of ppm and even hundreds of ppm, when being used to monitor the number of chemical substance sensor, developed the relevant detection device, and established effective and feasible detection method, thereby finished invention.

Claims (30)

1. be used to detect organic compounds such as saturated carbon compound, unsaturated carbon compound, aromatic series carbon compound, lipoid substance, ethers, and the optical-fiber chemical sensor of the gas of the nonpolar chemical material of mineral compounds such as water, nitrogen, oxygen and liquid and solution thereof its constitute: (a) by the core that polar polymer constituted (1) that contains more than one at least; (b) coat this core the outside, by the covering that polar polymer constituted (2) that can act on mutually with tested chemical substance that contains more than one at least.

2. by on main chain and/or person's side chain, containing more than one polar groups, and because its polarity of symmetry that these polar groups dispose mutually and the described optical-fiber chemical sensor of claim 1 of the core that non-polar polymer constitutes of being cancelled each other.

3. above-mentioned core be polymethyl methacrylate and/or polycarbonate be used to detect the gas of flammable carbon compound and the optical-fiber chemical sensor of liquid and solution.

4. covering is by at least a above non-polar polymer that can react with the gas of above-mentioned nonpolar chemical material and liquid and solution thereof and other superpolymer, the optical-fiber chemical sensor of being recorded and narrated in claim 1 that oligomer or low molecular mixing form or the claim 2.

5. the optical-fiber chemical sensor of being recorded and narrated in the claim 1 or 2 that covering is made of at least a above superpolymer that only contains carbon element and protium.

Covering contain at least more than one the claim that polysiloxane-based material constituted 1 or claim 2 in the optical-fiber chemical sensor recorded and narrated.

7. the optical-fiber chemical sensor of being recorded and narrated in the claim 1 that constituted by the epoxy resin material that contains more than one of covering or the claim 2.

Covering by the glass temperature of at least a above macromolecular material at-150 ℃ of optical-fiber chemical sensors of being recorded and narrated to claim 1 between (the serviceability temperature upper limit-40 of sensor) ℃ or the claim 2.

9. covering is by Kynoar (x), and PSI (y) mixes with the ratio of X: Y (but X+Y=1) and form, and X is between 0.1 to 0.4; Y being used between 0.9 to 0.6 detected the gas of combustible hydrocarbon and the optical-fiber chemical sensor of liquid and solution.

10. covering is made up of with the ratio mixing of X: Y (but X+Y=1) Kynoar (x) and polyisoprene (y), and X is between 0.1 to 0.4; Y being used between 0.9 to 0.6 detected the gas of flammable carbon compound and the optical-fiber chemical sensor of liquid and solution.

11. it is 400 from molecular weight that covering contains a kind of at least, polymethylene more than 000, tygon, polybutylene, poly-n-butene, poly-cyclopentane, polypropylene, polyisobutylene, poly-cyclopentyl ethene, and molecular weight is 800, poly-cis-isoprene more than 000, molecular weight is 200, poly-trans isoprene more than 000, and poly-(1,2 butadiene), poly-(1,3 butadiene), poly-cyclohexyl ethene, that selects arbitrarily among the superpolymer groups such as poly-dibutyl itaconate is used to detect the gas of flammable carbon compound and the optical-fiber chemical sensor of liquid and solution.

12. be used to detect lower alcohols, higher alcohols etc. contain the compound of hydroxyl, organic acid contains the compound of carboxyl, ketone compounds, contain aminated compounds, contain amino compound, contain fine compounds, contain nitro compound, halogen contained compound, sulfocompound and siliceous compounds, it constitutes the gas of other oxygenatedchemicals isopolarity chemical substances and the optical-fiber chemical sensor of liquid and solution thereof: (a) by the core that non-polar polymer constituted (1) that contains more than one at least; (b) coat this core the outside, by the covering that polar polymer constituted (2) that can act on mutually with tested chemical substance that contains more than one at least.

13. by the polar group that contains more than one at least is from Si, SiO, S, SO, SO ₂, F, C1, Br, I, CN, NO, NO ₂, NR ₁R ₂, R wherein ₁With R ₂Can be identical also can be inequality, its composition can be select arbitrarily in H, alkyl, rare base, alkynyl, the aromatic radical, superpolymer or the oligomer of position on main lock or side chain constitute the optical-fiber chemical sensor of being put down in writing in the claim 12 of covering.

14. by at least a for the complex compound that contains metal be the optical-fiber chemical sensor that the claim 12 of superpolymer, the oligomer of feature, low covering that molecule constitutes is put down in writing.

15. by the halogenation superpolymer that contains a kind of halogen element at least is the optical-fiber chemical sensor of oxygen, nitrogen, carbon monoxide and the carbon dioxide of the superpolymer of feature note of the ancient Chinese or the oligomer core that has in the claim 12 to be recorded and narrated that constitutes covering.

16. optical-fiber chemical sensor by alcohols, ketone and the water of the core that has in the claim 12 to be recorded and narrated of superpolymer that contains phenolics or carboxyl at least or covering that oligomer constitutes.

17. the optical-fiber chemical sensor with feature that claim 1 or claim 12 record and narrate of the difference of the refractive index of covering and core between 0.005 to 0.025.

18. have core that claim 1 or claim 12 record and narrate and covering but its covering is the optical-fiber chemical sensor through crosslinkedization processing.

19. have above-mentioned feature covering, and coat again in this covering outside have against sunshine, waterproof, the optical-fiber chemical sensor with feature that claim 1 or claim 12 record and narrate of the thin layer of chemical reactions such as anti-oxidation, anti-reduction.

20. with any above-mentioned clad material, along fibre-optic length direction by fixed interval coat its core surface and the optical-fiber chemical sensor group that forms with feature that claim 1 or claim 12 record and narrate.

21. the optical-fiber chemical sensor net that combines with a plurality of optical-fiber chemical sensors with feature that claim 1 put down in writing to the claim 20 or sensor group, by suitable means.

22. by the pick-up unit that optical-fiber chemical sensor constituted, that be used to discern the saturated and unsaturated carbon compound of note that at least a discrepant or several claims 1 in the answer speed of the single component that contains a saturated hydrocarbon to 50 charcoal atoms, unsaturated carbon compound or potpourri, output signal strength, the differential curve characteristic are put down in writing in to claim 11 or claim 17 to claim 19.

23. by because of containing a saturated hydrocarbon to 50 charcoal atoms, the single component of unsaturated carbon compound or the concentration change of potpourri and cause its answer speed, output signal strength, and in the characteristics such as differential curve of response curve the claim 1 of at least a generation difference to claim 11, or one of the optical-fiber chemical sensor put down in writing to the claim 19 of claim 17 or several constituted, be used to discern the pick-up unit of the saturated and unsaturated carbon compound concentration of note.

24. a device that detects gas, liquid and the solution of chemical substance, it is characterized by at least and contain: sensor or sensor group that at least one claim 1 of a is put down in writing to the claim 20; Another has identical core and covering with this sensor or sensor group b, but is coated with not the sensor or the sensor group of the thin layer that acts on mutually with detected material again in its covering outside.

25. a device that detects gas, liquid and the solution of chemical substance, it is characterized by at least and contain: sensor or sensor group that at least one claim 1 of a is put down in writing to the claim 20; B can carry out another respective element that temperature, humidity, optics compensate to the sensor recorded and narrated in a item or sensor group.

26. a device that detects gas, liquid and the solution of chemical substance, it is characterized by at least and contain: sensor or sensor group that at least one claim 1 of a is put down in writing to the claim 20; B one dichotomous optical fiber, its one be connected with light-emitting device, and another strand is connected with infrared rays receiver; One of c is located at the reflection unit of the sensor or the sensor group other end.

27. a device that detects gas, liquid and the solution of chemical substance, it is characterized by at least and contain: sensor or sensor group that at least one claim 1 of a is put down in writing to the claim 20; First optical fiber of b is used to connect an end and the light-emitting device of this sensor (group), and the diameter of this optical fiber is identical with the diameter of the optical fiber that constitutes sensor or sensor group; Second optical fiber of c is used to connect sensor or sensor group's the other end and infrared rays receiver, and its diameter then is less than or equal to sensor or sensor group's core diameters.

28. a device that detects gas, liquid and the solution of chemical substance, it is characterized by at least and contain: sensor or sensor group that at least one claim 1 of a is put down in writing to the claim 20; The luminophor that b and this sensor or sensor group's a end directly are connected; The photoreceptor that c and this sensor or sensor group's the other end directly are connected; D is two occulters between illuminating source and photoreceptor and sensor respectively.

29. a device and a detection method that detects gas, liquid and the solution of chemical substance, it is characterized by at least and contain: sensor or sensor group that two optional claims 1 of a are put down in writing to the claim 20; B makes the end incident of light through first sensor or sensor group; C makes an end that reflexes to second sensor or sensor group through the reflecting body of first sensor or sensor group's the other end of light through being located at this sensor or sensor group; The light that d sees through second sensor or sensor group carries out the light receiving area reason by the photoreceptor of the other end that is located at this sensor or sensor group.

30. a device and a detection method that detects gas, liquid and the solution of chemical substance, it is characterized by at least and contain: optical-fiber chemical sensor or sensor group that a is put down in writing claim 1 to the claim 20, at least more than half-turn; B makes light be injected by the injection device of going into of an end that is located at this sensor or sensor group again; C carries out the light receiving area reason by the infrared rays receiver that is located at the other end.

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