Background technology
Electrically conductive ink a kind ofly conductive filler material is dispersed in the conducing composite material with certain viscosity, certain conductive characteristic made in macromolecule matrix, because electrically conductive ink has the characteristic of similar ink, therefore electrically conductive ink by printing, printing or can write out corresponding electron device with straight connecing.Electrically conductive ink abundant species, mainly contain gold system, silver system, copper system and carbon series conductive ink, carbon series conductive ink has realized reaching practical degree, but the electroconductibility of carbon series conductive ink is often lower, cannot be applied to high-end electronic product; Gold system electrically conductive ink cost is too high, cannot realize large-area applications; And copper system electrically conductive ink not resistance to oxidation, stability in use is poor.Silver system electrically conductive ink can reach good electroconductibility and silver itself compares resistance to oxidation, and therefore silver system electrically conductive ink becomes the most promising electrically conductive ink in future.
Micro-silver powder, silver nano-grain and nano silver wire are three kinds of conductive filler materials that silver system electrically conductive ink is conventional.But nano silver wire receives much concern, mainly because nano silver wire has excellent electroconductibility, (resistivity of body silver is 1.65 × 10
-6Ω cm, even and if oxidized rear oxidation silver still has very high electroconductibility) and the transparency, and nano silver wire has good flexibility.In addition, preparation method's comparative maturity of nano silver wire, the condition that can control to react generates different diameter, the nano silver wire of different lengths.The electrically conductive ink of nano silver wire of preparation not only can prepare flexible electronic circuit by modes such as printing, printings, can also spin coating, spraying, blade coating, etc. kinds of processes prepare flexible transparent conductive film and flexible wearable electronics.
Nano silver wire is a kind of monodimension nanometer material with high length-diameter ratio, it can be used as conductive filler material to be applied in electrically conductive ink often to have than silver powder, percolation threshold that silver nano-grain is lower.But nano silver wire self has stronger Van der Waals force, after making electrically conductive ink dry solidification easily there is physical agglomeration in nano silver wire in macromolecule matrix, is unfavorable for the structure of conductive network, often causes higher percolation threshold.The higher conducing composite material that makes of percolation threshold needs the nano silver wire of more numbers just can reach desirable electroconductibility, and too high filler number not only adds overall cost, and has a strong impact on the mechanical property of printing, printing goods.Therefore the percolation threshold reducing electrically conductive ink is not only conducive to the use number reducing conductive filler material, and greatly can also improve the electroconductibility of the dry rear goods of electrically conductive ink solidification.And promote that nano silver wire dispersion is in the base the key factor reducing percolation threshold.
Summary of the invention
The object of the invention is to the problem of easily reuniting in resin matrix for the dry rear nano silver wire of current electrically conductive ink solidification, develop a kind of simple, the dispersion of effective means promotion nano silver wire in resin matrix, prepare one and there is low percolation threshold electrically conductive ink.
To achieve these goals, the present invention adopts following technical scheme:
A preparation method for low percolation threshold electrically conductive ink, comprises the steps:
1) mixed with non-conductive nanoparticle dispersion liquid by nano silver wire dispersion liquid, make nano silver wire and non-conductive nano particle hybridization, assembling forms the hybrid of nano silver wire and non-conductive nanoparticle;
2) mixture is centrifugal, discard supernatant liquor and obtain gelatinous nano silver wire and non-conductive nano particle hybridization thing;
3) hybrid obtained is mixed with macromolecule matrix, and with obtaining low percolation threshold electrically conductive ink after solvent adjustment viscosity to 1 ~ 10Pas.
Further, described nano silver wire is the length-to-diameter ratio adopting the method such as polyol process, hydrothermal synthesis method to prepare is the metal silver nanowires of 100-1000;
Further, described non-conductive nanoparticle must be the zero dimension of rich surface hydroxyl, one dimension or two-dimensional nano particle, such as, one in titanium dioxide nano-particle, zinc oxide nano-particle, nano micro crystal cellulose, halloysite nanotubes, montmorillonite-based nano lamella, kaolin nanoscale twins, graphene oxide etc.;
Further, the size of the zero dimension of described rich surface hydroxyl, one dimension or two-dimensional nano particle must be nano level, the diameter of zero-dimension nano particle should lower than the diameter of nano silver wire, the length of 1-dimention nano particle should lower than the length of nano silver wire, and two-dimensional nano lamella should be individual layer or the minority layer nanometer sheet lower than 5 layers;
Further, described non-conductive nanoparticle and the mass ratio of nano silver wire are 2:1-1:8;
Further, the hydridization method of described nano silver wire and non-conductive nanoparticle is dropwise added drop-wise in certain density non-conductive nanoparticle dispersion liquid or by non-conductive nanoparticle dispersion liquid by certain density nano silver wire dispersion liquid to be dropwise added drop-wise in nano silver wire dispersion liquid in open container (as beaker, culture dish etc.), and drip careful vibration until hydridization success;
Further, the dispersion liquid of described nano silver wire and the dispersion agent of non-conductive nanoparticle dispersion liquid be following any one: deionized water, methyl alcohol, ethanol, Virahol, butanols, butyleneglycol, isoprene, acetone, tetrahydrofuran (THF), ethyl acetate, dimethyl sulfoxide (DMSO), methane amide, methylformamide, DMF and N-Methyl pyrrolidone; And nano silver wire and the concentration of non-conductive nanoparticle in dispersion liquid are 0.1-10mgmL
-1.
Further, the temperature range of described nano silver wire and the successful hydridization of non-conductive nanoparticle energy is-20oC ~ 80oC;
Further, the rotating speed of described whizzer is 1000 ~ 8000rpm;
Further, the described centrifuge time is 2 ~ 100 minutes;
Further, described macromolecule matrix is the one in epoxy resin prepolymer, water-and acrylate, urethane resin, terpolycyantoamino-formaldehyde resin, resol performed polymer, vinyl chloride-vinyl acetate copolymer resin;
Further, described hybrid accounts for the 2vol% ~ 20vol% of macromolecule matrix;
Further, the solvent of described adjustment viscosity is one or more in ethyl acetate, normal hexane, methyl alcohol, ethanol, deionized water, tetrahydrofuran (THF), methane amide, dimethyl formamide, and after regulating viscosity, electrically conductive ink viscosity should between 1 ~ 10Pas.
Compared with prior art, the present invention has following advantage and technique effect:
At guarantee electrically conductive ink high connductivity, (resistivity reaches 10
-4Ω cm) while, significantly can reduce the percolation threshold of matrix material, reduce the usage quantity of nano silver wire, improve the service efficiency of nano silver wire.In addition, due to the reduction of percolation threshold, electrically conductive ink has better flexibility solidify drying on substrate after, and this is significant to the exploitation of current flexible electronic circuit.
Embodiment
Below in conjunction with embodiment, the present invention is described in further detail, but embodiments of the present invention are not limited thereto.
embodiment 1:
At normal temperatures by 1mgmL
-1graphene oxide/deionized water dispersion liquid is slowly added drop-wise to 5mgmL
-1in nano silver wire/alcohol dispersion liquid, dropping limit, limit is stirred, vibration, and the mass ratio of nano silver wire and graphene oxide controls at 3:1; After nano silver wire and the co-precipitation of graphene oxide hydridization, it after centrifugal 40min, is discarded supernatant liquor and obtain gel nano silver wire/graphene oxide hybrid under 2000rpm rotating speed; The hybrid obtained and epoxy resin prepolymer are mixed (8vol% that hybrid accounts for epoxy resin prepolymer), then instill ethyl acetate adjustment viscosity to 5.0Pas, obtain low percolation threshold electrically conductive ink, now the volume specific resistance of electrically conductive ink is about 1.2 × 10
-4Ω cm.
embodiment 2:
By 0.5mgmL under 50oC
-1nano micro crystal cellulose/deionized water dispersion liquid is slowly added drop-wise to 2mgmL
-1in nano silver wire/acetone dispersion liquor, dropping limit, limit is stirred, vibration, and nano silver wire and nano micro crystal cellulose mass ratio control at 2:1; After nano silver wire and the co-precipitation of nano micro crystal cellulose hydridization, by its centrifugal 5min under 6000rpm rotating speed, discard supernatant liquor and obtain gel nano silver wire/nano micro crystal cellulose hybrid; The hybrid obtained and water-and acrylate (solid content 15wt%) are mixed (5vol% that hybrid accounts for water-and acrylate), instillation deionized water regulates electrically conductive ink viscosity to 2.0Pas, obtain low percolation threshold electrically conductive ink, now the volume specific resistance of electrically conductive ink is about 3.2 × 10
-4Ω cm.
embodiment 3:
By 0.1mgmL under 80oC
-1montmorillonite-based nano sheet/deionized water dispersion liquid is slowly added drop-wise to 10mgmL
-1in nano silver wire/alcohol dispersion liquid, dropping limit, limit is stirred, vibration, and the mass ratio of nano silver wire and montmorillonite-based nano sheet controls at 6:1; After nano silver wire and the co-precipitation of nano imvite nanometer sheet hydridization, by its centrifugal 20min under 4000rpm rotating speed, discard supernatant liquor and obtain gel nano silver wire/montmorillonite-based nano sheet hybrid; The hybrid obtained and resol performed polymer are mixed (3vol% that hybrid accounts for resol performed polymer), instillation tetrahydrofuran (THF) regulates electrically conductive ink viscosity to 4.0Pas, obtain low percolation threshold electrically conductive ink, now the volume specific resistance of electrically conductive ink is about 9.2 × 10
-4Ω cm.
embodiment 4:
By 2mgmL under-20oC
-1zinc oxide colloidal sol is slowly added drop-wise to 4mgmL
-1in nano silver wire/alcohol dispersion liquid, dropping limit, limit carefully vibrates, and the mass ratio of nano silver wire and zinc oxide nano-particle controls at 4:1; After nano silver wire and zinc oxide hybridization co-precipitation, by its centrifugal 2min under 8000rpm rotating speed, discard supernatant liquor and obtain gel nano silver wire/zinc oxide hybridization thing; The hybrid obtained and aqueous polyurethane are mixed (solid content 30wt%) mix (4vol% that hybrid accounts for aqueous polyurethane), instillation dehydrated alcohol regulates electrically conductive ink viscosity to 2.0Pas, obtain low percolation threshold electrically conductive ink, now the volume specific resistance of electrically conductive ink is about 6.2 × 10
-4Ω cm.