Nanofiber organic semiconductors: The effects of nanosize on the electrical charge transport and optical properties of bulk polyanilines

The electrical transport, optical, and microstructural properties of bulk polyaniline (PANI) and nano‐PANIs were investigated. A field emission scanning electron microscopy (SEM) image of bulk PANI showed macroscopic and aggregated granular particles. A SEM image of the nanostructured PANI showed the formation of one‐dimensional nano/microstructures. The formation of nanofibers was observed from the transmission electron microscopy image. The electrical conductivities of the bulk and nanostructured PANIs increased with increasing temperature, which indicated semiconductor behavior. The electrical conductivities of the bulk and nanostructured PANIs at room temperature were found to be 2.12 × 10^?5 and 1.80 × 10^?2 S/cm, respectively. The electrical conductivity of the nanostructured PANI was about 850 times higher than that of the bulk PANI. The obtained band gaps of the bulk and nanostructured PANIs were determined from diffuse reflectance measurements and were found to be 3.27 and 2.41 eV, respectively. The refractive index of the PANI samples changed from 1.3 to 1.61. The obtained results indicate that the electrical and optical properties of the PANI were inherently dependent on the nanostructure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of self‐doped poly(aniline‐co‐aminonaphthalene sulfonic acid) nanotubes

Self‐doped poly(aniline‐co‐aminonaphthalene sulfonic acid) (PANI‐ANSA) was synthesized by the copolymerization of 5‐aminonaphthalene‐2‐sulfonic acid (ANSA) and aniline. Scanning electron microscopy and transmission electron microscopy showed that the morphology of PANI‐ANSA synthesized at a high molar ratio of aniline to ANSA was nanotubular, but at a low molar ratio, only a granular morphology formed. A possible formation mechanism for nanotubes was proposed. PANI‐ANSA had better thermal stability than HCl‐doped polyaniline; the highest onset decomposition temperature was as high as 340°C because of ? SO₃H linked with the polymer backbone by a covalent bond. PANI‐ANSA was partially soluble in basic solutions, and its conductivity was between 10^?2 and 10^?4 S/cm, depending on the sulfonation degree. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1297–1301, 2003     

Synthesis and characterization of polyaniline/NiO nanocomposite

Spherical nickel oxide (NiO) nanoparticles were prepared by using nickel chloride as precursor in the ethylene glycol as solvent and urea as precipitant. The X‐ray diffraction study showed that NiO has single‐phase cubic structure with average crystallite size of 35 nm. The prepared NiO nanoparticles were incorporated into polyaniline (PANI) matrix during in situ chemical oxidative polymerization of aniline with different molar ratios of aniline: NiO (12 : 1, 6 : 1, and 3 : 1) at 5°C using (NH₄)₂S₂O₈ as oxidant in aqueous solution of sodium dodecylbenzene sulfonic acid, as surfactant and dopant under N₂ atmosphere. The synthesized composites have been characterized by means of X‐ray diffraction (XRD), thermogravimetric analysis, Fourier transform infrared (FTIR), scanning electron microscopy, TEM, and vibrating sample magnetometer for its structural, thermal, morphological, and magnetic investigation. The XRD and FTIR studies show that the NiO particles are in the composite. The room temperature conductivities of the synthesized PANI, PANI/NiO (12 : 1), (6 : 1), and (3 : 1) composites were found to be 3.26 × 10^?4, 1.88 × 10^?4, 1.5 × 10^?4, and 4.61 × 10^?4 S/cm, respectively. The coercivity (H_c) and remnant magnetization (M_r) of NiO, PANI/NiO NCs (12 : 1), (6 : 1), and (3 : 1) at 5 K was found to be 8.22 × 10^?2, 6.31 × 10^?2, 6.42 × 10^?2, 6.27 × 10^?2 T, and 6.64 × 10^?3, 1.83 × 10^?4, 3.07 × 10^?4, and 3.98 × 10^?4 emu/g, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Influence of the reaction temperature on polyaniline morphology and evaluation of their performance as supercapacitor electrode

The polyaniline (PANI) nanostructures of tubular, spherical, and granules morphologies were synthesized by chemical oxidation approach in different reaction temperatures and used as the active electrode materials of symmetric redox supercapacitors. X‐ray diffraction and scanning electron microscopy techniques are employed for characterization of these PANIs. With the initial and reaction temperature increase, the morphology of PANI turned from block to spherical and tubular. Electrochemical properties of these PANI electrodes are studied by cyclic voltammetry (CV), agalvanostatic charge–discharge test, and electrochemical impedance spectroscopy (EIS) in 1M H₂SO₄ aqueous solution. The highest electrochemical properties are obtained on the PANI with tubular morphology. The initial specific capacitance of tubular, spherical, and granules PANI are about 300, 300, and 290 F g^?1 at a constant current of 5 mA. Meanwhile, the retention of the tubular PANI capacitance after 500 charge–discharge cycles was 75%, whereas the spherical and granules PANI was only 35% and 57%. The results indicate that tubular PANI electrodes have potential applications as high‐performance supercapacitors electrode materials. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3753–3758, 2013     

Molecular composites obtained by polyaniline synthesis in the presence of p‐octasulfonated calixarene macrocycle

Polyaniline (PANI) molecular composites were synthesized by chemical oxidative polymerization of the aniline and aniline dimer, N‐phenyl‐1,4‐phenylendiamine, in the presence of a macrocycle, calix[8]arene p‐octasulfonic acid (C8S), using ammonium peroxidisulfate as oxidant. The macrocycle has acted both as acid dopant and surfactant to obtain processable PANI‐ES. The PANI/calix[8]arene p‐octasulfonic acid composite was also obtained by a simple doping of PANI emeraldine base form with calix[8]arene sulfonic acid. The structure of materials was confirmed by Fourier transform infrared, UV–vis and nuclear magnetic resonance spectroscopy. All synthesized composite materials are amorphous and soluble in chloroform, dimethylsulfoxide, NMP, showing excellent solution‐processing properties combined with electrical conductivity. Cyclic voltammetry evidenced a good electroactivity for the composite films. Dielectric properties (dielectric constant and dielectric losses) were determined and are comparable with those of other PANI/ionic acid polymer composites. Preliminary studies have evidenced a high dielectric constant (10⁴ at 100 Hz) and electrical conductivity of 6 × 10^?3 S/cm for PANI composites. From sulfur elemental analysis of the PANI/calixarene, it results that the content in macrocycle is ～30% (weight). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Investigation of the behavior of hydrogen‐bonded phenolic compounds and their determination by using poly(vinylferrocenium)–polyaniline composite film

The hydrogen bonding between phenolic compounds (phenol (Ph), catechol (Ct), resorcinol (Rs), and hydroquinone (Hq)) is investigated at pH 4. The oxidation behaviors of total phenolic compounds (TotPh) are different from their individual behaviors due to the existence of intermolecular hydrogen‐bonded oligomeric clusters. Theoretical calculations and voltammetric and spectroscopic evidences support the intermolecular hydrogen bonding. The interaction of the phenolic compounds with polyaniline (PANI) and poly(vinylferrocenium) (PVF⁺) films are also investigated electrochemically and spectroscopically. The phenolic molecules are immobilized in both polymers due to the construction of hydrogen bonds by PANI and the complexation with PVF⁺. In addition, Ct and Hq are catalytically oxidized by PANI. Determinations of Ct and TotPh are performed on PVF⁺–PANI composite ‐ coated Pt electrode using amperometric I–t method. Composite coating exhibits significant electrochemical activity toward Ct and TotPh, with high sensitivity and a wide linearity range. The steady‐state currents versus concentration of Ct and TotPh are found to be linear in the range of 1.35 × 10^?3?50.0 mM and 4.10 × 10^?4?560 mM for two linear regions, respectively. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43596.     

The unique morphology role of thorn surface in determining electrochemical performance of polyaniline nano‐fibers via one‐step method

Polyaniline nano‐fibers with thorn surface morphology (T‐PANI) were synthesized by one‐step polymerization with adding additional aniline at later stage of chemical oxidation synthesis. In order to investigate the morphology role in determining electrochemical performance, the nano‐fibers PANI without thorn (PANI) was synthesized by the same polymerization process but at different time to add additional aniline. Material structures were characterized by field emission scanning electron microscope and Brunauer‐Emmett‐Teller method, and electrochemical performance was tested through cyclic voltammograms, galvanostatic charge‐discharge and electrochemical impedance spectroscopy. The data showed that the specific capacitance of T‐PANI was 443 F g^?1 at 5 mA cm^?2, which was much more than that of PANI (338 F g^?1 at 5 mA cm^?2). The solution resistance, charge transfer resistance, and diffuse resistance of T‐PANI were also lower than these of PANI. The results indicate that the thorn surface structure plays an important role in determining the electrochemical performance of polyaniline, which attribute to the improvements in pore size, pore distribution, special surface area, and conductivity. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42266.     

Improvement of conductivity of electrochemically synthesized polyaniline

The electrochemical polymerization of aqueous solution of aniline and HCl was carried out in a single compartment electrochemical cell. After 2 h of the polymerization reaction, polarity of the electrodes was reversed and kept for 1 h. By this process the conductivity of the polyaniline (PAni) formed was found to increase dramatically from 1.1 × 10^?4 to 3.0 × 10^?1 S/cm. The PAni samples obtained both by reversing the polarity (“PANI‐R”) and without reversing the polarity (“PANI”) were characterized by the infrared spectroscopy (FT‐IR), thermogravimetric analysis (TGA), ultraviolet spectroscopy (UV), Hall effect experiment, X‐ray analysis (XRD) and scanning electron microscope (SEM). The results show that the increase in the conductivity of PAni through the reversion of polarity is due to the partial reduction of over oxidized sample giving more emeraldine base and hence more polaron formation with increased charge carrier density and its mobility. The degree of crystallinity and the crystallite size is decreased marginally and the d‐spacing is increased marginally due to this reduction. The PAni behaves like a p‐type semiconductor that means the majority current carriers are holes. A plausible reduction mechanism due to reversal of polarity during electrochemical polymerization is also proposed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Facile preparation of conductive paint made with polyaniline/dodecylbenzenesulfonic acid dispersion and poly(methyl methacrylate)

We investigated an easy way to prepare industrially a conductive paint made with polyaniline (PANI)/dodecylbenzenesulfonic acid (DBSA) dispersion and poly(methyl methacrylate) (PMMA) in organic media. First, water‐dispersible PANI doped with DBSA was chemically synthesized with aniline sulfate using ammonium persulfate in water, and the resulting PANI/DBSA was readily extracted from the reaction medium with a mixture of toluene and methyl ethyl ketone (MEK) (toluene:MEK = 1:1 (v/v)), which is useful for industrial applications. The obtained PANI/DBSA organic dispersion was mixed with PMMA organic solution to give the corresponding PANI/DBSA conductive paint containing PMMA. A film prepared with the resulting PANI/DBSA conductive paint was found to possess relatively good conductivity and low surface resistivity for a conductive paint utilized for an electrostatic discharge even at low PANI/DBSA content in the PANI/DBSA–PMMA composite film (the conductivity and the surface resistivity were 9.48 × 10^?4 S cm^?1 and 3.14 × 10⁶ Ω cm^?2, respectively, when the feed ratio of PANI/DBSA:PMMA was 1:39 (w/w)). Furthermore, it was found that the conductivity of the film composed of PANI/DBSA–PMMA composite can be readily and widely controlled by the PANI/DBSA content of the composite or by the amount of DBSA used during the PANI/DBSA synthesis. The highest conductivity of PANI/DBSA–PMMA composite film (7.84 × 10^?1 S cm^?1) was obtained when the feed ratio of PANI/DBSA:PMMA was 1:4 (w/w). Copyright © 2007 Society of Chemical Industry     

The Effect of External Mass Transfer Resistance during Drying of Fermented Sausage

The drying mechanism of fermented sausages (sucuks) that were cylindrical rod shaped, 40 cm long and 4 cm diameter, during ripening under natural convection conditions at different temperatures (15 to 30°C) was examined. To simulate the experimental drying curves, three empirical models and a diffusional model assuming negligible external mass transfer resistance were evaluated. The drying rate curves of sucuk samples were also simulated taking into account the influence of the external mass transfer resistance. The equation was solved using the trial-and-error solution algorithm developed in this study and the mass transfer coefficient, k _c , and effective moisture diffusivity, D _eff , were simultaneously determined (1.44 × 10^?8 to 1.93 × 10^?8 m/s and 4.30 × 10^?10 to 6.85 × 10^?10 m²/s, respectively). The proposed model considering the effect of external resistance allowed the accurate simulation of the experimental drying data of sucuks at different temperatures.     

Electrically conductive nanocomposites of polyaniline with poly(vinyl alcohol) and methylcellulose

Electrically conductive nanocomposites of HCl‐doped polyaniline (PANI–HCl) nanocolloid particles with water‐soluble and film‐forming polymers such as poly(vinyl alcohol) (PVA) and methylcellulose (MC) were prepared by the redispersion of preformed MC‐coated submicrometric PANI–HCl particles in PVA and MC solutions under sonication for 1 h and the casting of the films from the dispersions followed by drying. The submicrometric polyaniline (PANI) particles were prepared by the oxidative dispersion polymerization of aniline in an acidic (1.25M HCl) aqueous ethanol (30 : 70) medium with MC as a steric stabilizer. The particles contained 4.7 wt % MC and had a conductivity of 7.4 S/cm. They had an oblong shape of 203 nm (length) and 137 nm (breadth). Sonication broke the oblong‐shaped particles to sizes of ～10 nm in the PVA matrix and ～60 nm in the MC matrix. The electrical conductivity of these films was measured, and the percolation threshold was determined. The composites had the characteristics of a low percolation threshold at a volume fraction of PANI of 2.5 × 10^?2 in the PVA matrix and at a volume fraction of 3.7 × 10^?2 in the MC matrix. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Polyaniline-Coated Short Nylon Fiber/Natural Rubber Conducting Composite

Natural rubber-Polyaniline (PANI)-Polyaniline coated short nylon-6 fiber (PANI-N6) composites were prepared by mechanical mixing and its cure characteristics, filler dispersion, mechanical properties, conductivity and thermal stability were evaluated. PANI was synthesized by chemical oxidative polymerization of aniline in presence of hydrochloric acid. PANI-N6 was prepared by in situ polymerization of aniline in the presence of short nylon-6 fiber. The composite showed higher tensile strength, tear strength and modulus values and lower elongation at break. The DC electrical conductivity and the thermal stability of the composites increased with PANI and PANI-N6 concentration. The highest conductivity obtained was 1.99 × 10^?6 S/cm.     

Preparation and self‐assembly of polyaniline nanorods and their application as electroactive actuators

To improve the performance of ion‐exchange polymer–metal composite (IPMC) actuators, an electrical pathway material for enhancing the surface adhesion between the membrane and the metal electrodes of the IPMC was studied. As an efficient electrical pathway material, polyaniline nanorods (PANI‐NRs) doped with p‐toluene sulfonic acid (TSA) were synthesized with a template‐free method. The factors affecting polyaniline morphology were studied with various dopant concentrations and oxidant feeding rates. Highly conductive PANI‐NRs were formed when they were synthesized with ammonium persulfate at a 5.0 mL/min oxidant feeding rate and doped with 0.125M TSA. The conductivity of the PANI‐NRs was 1.15 × 10^?1 S/cm, and their diameters and lengths were 120–180 nm and 0.6–2 μm, respectively. To apply the membrane as an actuator, perfluorosulfonated ionomer (Nafion)/PANI‐NR blends were prepared by solution blending and casting. The actuating ability of the three‐layered membrane consisting of Nafion/PANI‐NR blends was then examined and compared with that of Nafion only. The actuating ability of the IPMC was improved when Nafion/PANI‐NRs were used as electrical pathways. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Photo‐induced protonation and conductivity of polyaniline/poly(ethylene glycol) and polyaniline/[poly(ethylene glycol)‐grafted polyaniline] composites

Composites of polyaniline in its emeraldine base form (PANI‐EB) and photo‐acid generators (PAG) show an increase in conductivity upon photo‐irradiation due to the protonation of PANI‐EB. Such materials may be utilized to fabricate conducting patterns by photo‐irradiation. However, the conductivity obtained by direct irradiation of PANI‐EB/PAG composites was normally quite low (<10^?3 S/cm) due to aggregation of highly loaded PAG. In this work, poly(ethylene glycol) (PEG), which is a proton transfer polymer, was added to PANI‐EB/PAG. Results showed that addition of low M_w (550) PEG significantly enhance the photo‐induced conductivity. Conductivities as high as 10^?1–10⁰ S/cm were observed after photo‐irradiation. This conductivity is comparable to that of PANI‐salt synthesized by oxidizing aniline in the presence of an acid. High M_w (8000) PEG is much less effective than PEG 550, which is attributed to its lower compatibility with PANI. PEG‐grafted PANI (N‐PEG‐PANI) was also studied as an additive. Composites of PANI‐EB and N‐PEG‐PANI showed conductivity as high as 10² S/cm after treatment with HCl vapor. The photo‐induced conductivity of the N‐PEG‐PANI/PANI‐EB/PAG composite reached 10^?2–10^?1 S/cm. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

In situ preparation of polyaniline within neutral,anionic, and cationic superporous cryogel networks as conductive,semi‐interpenetrating polymer network cryogel composite systems

Polyaniline [p(An)], one of the most known conducting polymers, was prepared within superporus nonionic polyacrylamide [p(AAm)], anionic poly(2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid sodium salt) [p(AMPS)], and cationic poly(3‐acrylamidopropyltrimethyl ammonium chloride) [p(APTMACl)] cryogels. After they were synthesized, washed, and dried, the neutral p(AAm), anionic p(AMPS), and cationic p(APTMACl) cryogels were soaked in an ammonium persulfate/aniline solution (1:1.25 ratio) in 1 M hydrochloric acid for the in situ oxidative polymerization of p(An) with the cryogel matrices as templates or reactors. The prepared p(AAm)/p(An), p(AMPS)/p(An), and p(APTMACl)/p(An) semi‐interpenetrating polymer network (semi‐IPN) conductive cryogel composites were characterized with scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and conductivity analysis. The SEM images revealed that the superporus cryogel networks were almost completely filled with p(An) conductive polymers (CPs). Among the cryogel–CP semi‐IPNs, we found that p(AAm)/p(An) semi‐IPN conductive cryogel composites provided the highest conductivity values of 1.4 × 10^?2 ± 4 × 10^?4 S/cm; this was a 6.4 × 10⁶ fold increase in the conductivity from the values of 2.2 × 10^?9 ± 1 × 10^?10 for p(AAm) cryogels. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44137.     

Preparation of polyaniline/vermiculite clay nanocomposites by in situ chemical oxidative grafting polymerization

BACKGROUND: Recently, conducting polymers have attracted much attention, since they have interesting physical properties and many potential applications, such as in conductive coating charge storage. Hence the synthesis of conducting polymer nanocomposites is also an area of increasing research activity. RESULTS: Vermiculites (VMTs) were successfully delaminated using an acid treatment. Polyaniline (PANI)/VMT nanocomposites were prepared by in situ chemical oxidative grafting polymerization. CONCLUSION: The chemical grafting of PANI/VMTs was confirmed by Fourier transform infrared and UV‐visible spectroscopy. The percentage of grafted PANI was 142.7 wt% as a mass ratio of the grafting PANI and charged nano‐VMTs, investigated using thermogravimetric analysis. In addition, characteristic agglomerate morphology of PANI was observed in the composites using scanning electron microscopy. Thermal analyses indicated that the introduction of VMT nanosheets had a beneficial effect on the thermal stability of PANI. The electrical conductivity of the nanocomposites was 3.9 × 10^?3 S cm^?1, a value typical for semiconductors. Copyright © 2009 Society of Chemical Industry     

Poloxamer and gelatin gel guided polyaniline nanofibers: synthesis and characterization

A rapid polymerization technique was successfully employed to synthesize interconnected polyaniline (PANI) nanofibers using chemical oxidative polymerization inside a soft template. The thermoreversible hydrogels of Lutrol F 127 and gelatin were used as templates where the interstices present in the hydrogel were responsible for the formation of PANI nanofibers with a diameter in the range ca 70?75 nm and ca 50?55 nm respectively and several micrometers in length. The doped emeraldine salt of PANI was confirmed by Fourier transform infrared spectroscopy and ultraviolet–visible spectroscopy. The crystallinity of as‐synthesized PANI nanofibers for both cases was verified by an X‐ray diffraction study while thermogravimetric analysis was performed to compare the relative stability of the synthesized PANI nanofibers. The electrical conductivities of polymerized PANI are of the order of 10^?3 S cm^?1 and are compared with those of template fabricated PANI. The Lutrol F 127 gel guided PANI nanofibers showed a rectifying property while the gelatin gel guided PANI provided a simple ohmic nature. © 2013 Society of Chemical Industry     

Synthesis and Characterization of Low-Cost Electroactive Hybrid Composites Derived From Polyaniline and NiS

The synthesis and characterization of conducting polyaniline (PANI) salt and nickel sulfide (NiS) hybrid composites are reported in this study. The PANI-NiS hybrid composites showed nearly two orders of magnitude higher than that of pure PANI. The specific conductivities of PANI and PANI-NiS hybrid composites (2% and 20% by weight) were found to be 5.1 × 10^?4, 1.6 × 10^?2, and 3.8 × 10^?2 S/cm. The polarity of Hall voltage of the hybrid composite was found to be negative indicating that the PANI-NiS composite is an n-type semiconductor. The composites pellets were characterized by XRD, SEM and FTIR and the results were compared.     

Electrically conductive polyaniline/polyimide microfiber membrane prepared via a combination of solution blowing and subsequent in situ polymerization growth

Dodecylbenzene sulfonic acid (DBSA) doped-polyaniline (PANI) coated conductive polyimide (PI) microfiber membrane was prepared by chemical oxidation polymerization. PI nanofiber membrane was prepared by solution blowing. Fourier transform infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) proved that the successful preparation of composite microfiber membrane with core-shell structures. At the same time, the PANI had an effect of protection on PI nanofiber, which was detected by thermal gravimetric analysis (TGA). The orthogonal experiments were designed to determine the optimal reaction conditions for the conductivity of PANI/PI microfiber membranes as following: ANI concentration (0.15 mol L^?1), APS concentration (0.1 mol L^?1) and DBSA concentration (0.3 mol L^?1). The conductivity of PANI/PI microfiber membranes could arrive to 3.83 × 10^?2 S cm^?1. Moreover, the PANI/PI microfiber membranes had a superior hexavalent chromium (Cr (VI)) adsorption performance. The factors affecting the performance of hexavalent chromium (Cr (VI)) removal from the aqueous solutions were investigated.     

Potential of integrating Na2SO4 · 10H2O pellets in solar drying system

In the current study, evolution of thermophysical properties of red chilli dried in a mixed mode solar dryer that integrates sodium sulfate decahydrate (Na₂SO₄?·?10H₂O) and sodium chloride (NaCl) as thermal storage were presented. Solar drying with Na₂SO₄?·?10H₂O reduced the drying time by 26.7 and 39%, compared to the drying time with or without NaCl. Dimensional shrinkage was gradual with a nonlinear exponential shape for the whole drying conditions. The evolution of the bulk and particle densities decreased while the porosity of the seed increased with time. The coefficient of heat and mass transfer varied from 0.0036???0.035?W/m²?K to 6.09?×?10^?9???6.2?×?10^?8?m/s, respectively. The thermal conductivity, specific heat capacity, and thermal diffusivity ranged from 0.0568 to 0.1093?W/m?K, 1,072 to 2218.7?J/kg?K, and 4.7?×?10^?5 to 5.13?×?10^?5?m²/s, respectively.