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Comparison of Electrorheological Characteristics Obtained in Two Geometrical Arrangements:
Parallel Plates and Concentric Cylinders
Petra Peer1, a), Petr Filip1, b), Martin Stenicka2, c) and Vladimir Pavlinek2, d)
1Institute of Hydrodynamics, Acad. Sci. Czech Rep., Pod Patankou 5, 166 12 Prague, Czech Republic 2Centre of Polymer Systems, University Institute, Tomas Bata University in Zlín,
Nad Ovčírnou 3685, 760 01 Zlín, Czech Republic
a)Corresponding author: [email protected] b)[email protected]
c)[email protected] d)[email protected]
Abstract. The electrorheological characteristics of suspensions of PANI powders suspended in silicone oil measured by a rotational rheometer Physica MCR 501 (Anton Paar Co.) are compared for two different geometrical arrangements – parallel plates and concentric cylinders. The individual differences in the results of the measured parameters are discussed.
INTRODUCTION
The general validity and reproducibility of rheological measurements in various laboratories is neither simple nor obvious in spite of the permanent development of new sophisticated rheometers. There is a coincidence of ‘classical’ rheological characteristics (such as, e.g., shear viscosity) measured for common classical materials. However, for more complicated characteristics and materials the results are quite often different. This can be documented from the examples of M1 and A1 projects carried out in a considerable number of prominent laboratories round the world (Sridhar [1], Hudson and Jones [2]). The non-coincidence of elongational viscosity is remarkable. As the materials used were identical, it proves that other complementary attributes connected with rheological measurements substantially participate in the proper analysis of the studied materials. Generally, among other things, it is possible to mention the process of the preparation of the measured samples, the adequacy of their volume for an applied geometrical arrangement, the materials of which contact surfaces are made, the stability of rheometers, etc. The same problems concern not only measuring the rheological characteristics of the same material in different laboratories, but also measuring the same material at the same laboratory using different rheometers (Rides et al. [3]) or the same rheometer but with various geometrical arrangements (Modigell and Pape [4]).
The literature describing and analysing this discrepancy is very scarce and does not correspond to the significance of the problem, which is further emphasized with the onset of a new generation of so-called smart materials such as those now appearing in magneto- or electro-rheology.
Electrorheological (ER) fluids quickly and reversibly change their structure under the application of an external electric field. The formation of a chain-like structure occurs due to particle polarisation in the direction of an electric field. A number of studies of this mechanism have been summarized in several review papers (Block and Kelly [5], Jordan and Shaw [6], Block et al. [7], Parthasarathy and Klingenberg [8], See [9], Hao [10,11], Sheng and Wen [12]). Most commercially available rheometers can be equipped with ER cells making full use of the functionality of the host instruments. In principle, these devices differ according to the geometry applied – with either parallel plates or concentric cylinders.
Novel Trends in Rheology VIAIP Conf. Proc. 1662, 040005-1–040005-8; doi: 10.1063/1.4918893
© 2015 AIP Publishing LLC 978-0-7354-1306-1/$30.00
040005-1
In the protational parallel plmaking a u
An eleg.mol-1) wconcentrativacuum ova scanning
The DCdeterminedPANI samp
A rotatarrangemenused were the inner aselected teplate for thwire adhersupply off.The intens(F.u.G. Elethe conditi
To prevFig. 2.
present study, trheometer are ates or concen
unique interpre
ctrorheologicawith silicone oions. PANI poven to a constan electron microC conductivityd by a four-poples attained 7
tional rheometents, parallel plas follows: P-P
and outer diamemperature (allhe parallel plaring to an uppe. The rheometeity of the electektronik GmbHon that the elecvent the vibrati
the experimentused, were co
ntric cylindersetation of the rh
al suspension woil (Lukosiol Mwder was grount weight. Figuoscope VEGA
y of PANI baseoint method in.72 x 10-9 S.cm
F
er Physica MClates and concPTD200/E para
meter 16.6 mm l measurementte arrangemener shaft compler itself was fultric field was vH, Rosenheim,ctric current diions caused by
tal data (flow compared. The . As documen
heological char
EXPE
M
was prepared bM200, Chemiund, sieved to oure 1 illustrates3 (Tescan, Cz
e particles pres a van der Pau
m-1.
FIGURE 1. SEM
CR 501 (Antoncentric cylindeallel plates of dand 18 mm, r
ts were carriednt and the cup leted a circuit lly isolated fro
varied through , Germany). Itid not exceed 1y the surroundin
characteristics)only change
nted below, evracterisation of
ERIMENTA
Material
by mixing PAical Works Koobtain particle s the morpholoech Republic).ssed into pelleuw setup (Stej
M pictures of PA
Device
Paar Co.) equers, was emplodiameter 50 mmrespectively. Ed out at 20°C)
in the concentloop, and openm an electric can external DC
t provided an e1 mA (otherwisng influences,
) when the samwas in the ap
ven in this casf the chosen m
AL
ANI powder (Solin, Czech Rsizes smaller t
ogy and wide d. ets (13 mm in jskal and Gilb
ANI powder.
uipped with twoyed. The dimm, C-PTD200/
Each geometry was controlled
ntric cylinder gning the hood current by an inC high voltageelectric field sse voltage was the rheometer
me electro-rheopplied geometrse it is necessaterial.
Sigma Aldrich,Republic) in 5than 45 μm, an
distribution of P
diameter, 1 mbert [13]). The
wo ER cells in dmensions of the
/E a bob and cwas covered wd by Peltier el
geometry were automatically
nsulator insertee power supplystrength up to proportionallywas accommo
ological materirical arrangemsary to be care
, USA, base, 55, 10, and 15 nd dried at 80°PANI particles
mm in thicknese conductivity
different geome measuring syup arrangemenwith a hood, alements. The bgrounded. A switched the
ed in the uppery unit HCP 14-12.5 kV.mm-1
y reduced). odated as sketc
ial and ments –
eful in
50,000 wt.%
°C in a s using
s) was of the
metrical ystems nt with and the bottom spring power
r shaft. -12500
under
ched in
040005-2
FIGURE
For a mfor PP geo
Due to measurememeasureme
A basicmeasuremebetween thshaft). Theapparent. Thood. As ethe range 1
E 2. Sketch of th
more adequate cmetry adjustedthe presence
ents merely in ent of a studied
FIGUR
c introductory ent is documenhe spring wire e 'non-homogeTherefore, all mexpected, the m1-100 s-1.
he rheometer supbo
comparison, ind). Prior to the of friction betwair (see Figs.
d material. In th
RE 3. Measurem
Measureme
comparison onted in Fig. 5. and shaft), an
eneous' influenmeasurements measurements
pport (each ‘leg’oard, 70 tennis b
R
n all the measurmeasurementsween the sprin3 and 4). Thenhe following, a
ment of shear visc
ents of Silic
of both geomeMeasurements
nd at the bottomnce of the sprcarried out in of the shear vi
’ consists of a steballs, and iron bo
RESULTS
rements a gap both experime
ng wire and upn this value haall the measure
cosity in differen
cone Oil with
tries was carris on the top wm with an opering wire on the absence ofiscosity of the
eel box, sieved soard (75 kg)).
of 0.7 mm waental geometriepper shaft, it wad to be subtraced data were pr
nt geometries wi
h No Electr
ied out with awere carried ouen hood (no cothe viscosity f electric field
e Newtonian si
sand (0.6 ≈ 0.8 m
s held out (for es were calibra
was first necesscted from the rocessed in this
ith the 'empty' ce
ric Field
a carrier liquidut with a closedontact between
values for smstrength were
ilicone oil wer
mm, 400 kg), pla
CC geometry ated. sary to carry odata obtained s way.
ell.
d - silicone oild hood (with c
n the spring wimall shear rate
taken with thee almost ident
astic
given,
out the during
l. This contact ire and es was e open tical in
040005-3
Stsh
Asw
Frsw
FIGURE 4.
FIGURE 5
teady hear
Amplitude weep
requency weep
Measurement o
5. Flow curve of
TABLE
Shear rate Duration Voltage Shear rate Strain Duration Voltage Shear rate Frequency Duration Voltage
of storage and lo
f the silicone oil
E 1. Measureme
Mixing 10 s-1 30 s 0 V 10 s-1 30 s 0 V 10 s-1 30 s 0 V
oss moduli in dif
l (E = 0 kV.mm-
ent parameters in
Pause 0 s-1 30 s 0 V 0 s-1 30 s 0 V 0 s-1 30 s 0 V
fferent geometrie
1), left: open hoo
n individual mod
0 s-1 60 s xxx V 0 s-1 60 s xxx V 0 s-1 60 s xxx V
es with the 'emp
od, right: closed
des.
Measurement 0.01 - 100 s-1 (00.01 - 100 s-1 (x
0.0001 – 0.01[-]0.0001 – 0.01[-] 0.1-10 Hz / 0.000.1-10 Hz / 0.00
pty' cell.
d hood.
0 V) xxx V)
] / 5 Hz (0 V) ] / 3 Hz (xxx V)
01 [-] (0 V) 006 [-] (xxx V)
040005-4
Electrousing botheach measuand frequeindividual point in thsweep andprolonged
For sheviscosity oparticles. Fshear rate 0become lefrequency suspension
orheological chh ER cells. Theurement. Cons
ency sweep). Tvalues of volta
he steady shead frequency swwith lower val
ear mode, Figsof oil) for both Figure 9 presen0.23 s-1. This lss significant. for both geom
ns with 5 and 1
FIGURE 6. R
FIGURE 7. Re
Rheolog
haracteristics oe samples werequently, comphe courses of tage as indicate
ar flow measurweep) was mealues of the stud. 6-8 compare geometries (PPnts a mutual colower shear ratThe comparis
metries is prese5 wt.% concen
Relative viscosity
elative viscosity
gical Measur
of the suspense stirred mechparisons were the measuremeed in the figurerements as weasured at leastdied characteristhe behaviour
P 50 and CC 1omparison of fte value was chson concerningented for 10 wntration is analo
y in dependence
in dependence o
rements of E
ion (shear vishanically and thmade for threeents (time interes), range of mell as in the smt three times. stics. of relative vis7) consequentlflow behaviouhosen intentiong the dependenwt.% concentraogous.
on shear rate of
on shear rate of P
ER Suspens
scosity, storagethen placed in e different modrvals, electric f
measured pointmall-strain oscThe time of m
scosity (ratio oly for 5, 10, an
ur for the abovnally, as for hignce of viscoelaation in Figs. 1
f PANI suspensio
PANI suspensio
sions
e and loss moan ultrasonic
des (steady shefield strength (ts) are summarcillatory tests measurement w
f the viscosity nd 15 wt.% conve-stated concegher values theastic moduli o10 and 11. Th
on (5 wt.% conc
on (10 wt.% conc
oduli) were obbath for 30 s ar, amplitude s
(xxx V stands frised in Tab. 1(dynamic amp
was correspon
of suspensionncentrations of entrations at coe studied diffe
on strain and ahe flow behavi
entration).
centration).
btained before sweep, for the . Each plitude
ndingly
n to the f PANI onstant erences angular iour of
040005-5
FIGURE 9
The exThis fact isusing extru
There i- different - different - differenc- more com- anti-shoc- different - possible
in combi- the way o- different
FIGURE 8. Re
9. Flow behavio
xperimental dats not surprisingusion rheometeis a series of regeneration of flow condition
ce in contact sumplicated (trimck balancing ingeneration of appearance of nation with poof calculating rsedimentation
elative viscosity
our of different c
ta obtained forg: cf. e.g. Rideers (the same measons for this dflow; ns for suspendeurface; mming) placemn the laboratoryan electric fielwall slip (Mod
ossible sedimenrheological cha
n times of ER fl
y in dependence o
concentrations ofat fixed s
DIS
r the two geomes et al. [3], whmanufacturer) indeviation:
ed particles;
ent of suspensiy (significant fod (radial vs. pldigell and Papentation); aracteristics frofluids in differe
on shear rate of
f PANI powder shear rate (0.23
SCUSSION
metrical arrangho compared shncluding an in
ion into paralleor lower valueslan-parallel, seee [4], Barnes [1
om raw data geent geometries.
PANI suspensio
in silicone oil ins-1).
ements exhibithear viscosity
nstrumented inj
el plate geomets of independee Fig. 12); 14]) (+ differen
enerated by eith
on (15 wt.% conc
n dependence on
t some degree results obtaineection mouldin
try; ent variables);
nt manifestatio
her geometry;
centration).
n electric field str
of non-coincied at high sheang machine.
on in either geo
rength
dence. ar rates
ometry
040005-6
FI
FIG
F
IGURE 10. Sto
GURE 11. Stora
FIGURE 12. Ra
orage and loss m
age and loss mod
adial and plan-pa
moduli in depend
duli in dependen
arallel orientatio
dence on strain o
nce on frequency
on of an electric f
of PANI suspens
y of PANI suspen
field generated i
sion (10 wt.% co
nsion (10 wt.% c
in the individual
oncentration).
concentration).
l geometries.
040005-7
ACKNOWLEDGMENTS
The authors wish to acknowledge the RVO: 67985874.
REFERENCES
1. T. Sridhar, J. Non-Newtonian Fluid Mech. 35, 85-92 (1990). 2. N. E. Hudson and T. E. R. Jones, J. Non-Newtonian Fluid Mech. 46, 69-88 (1993). 3. M. Rides, A. L. Kelly and C. R. G. Allen, Polym. Test. 30, 916-924 (2011). 4. M. Modigell and L. Pape, Solid State Phenomena 141-143, 307-312 (2008). 5. H. Block and J. P. Kelly, J. Phys. D: Appl. Phys. 21, 1661-1667 (1988). 6. T. C. Jordan and M. T. Shaw, IEEE Trans. Electr. Insul. 24, 849-878 (1989). 7. H. Block and J. P. Kelly, A. Qin and T. Watson, Langmuir 6, 6-14 (1990). 8. M. Parthasarathy and D. J. Klingenberg, Mater. Sci. Eng. R 17, 57-103 (1996). 9. H. See, Korea-Austr. Rheol. J. 11, 169-195 (1999). 10. T. Hao, Adv. Mater. 13, 1847-1857 (2001). 11. T. Hao, Adv. Colloid Interface Sci. 97, 1-35 (2002). 12. P. Sheng and W. Wen, Ann. Rev. Fluid Mech. 44, 143-174 (2012). 13. J. Stejskal and R. G. Gilbert, Pure Appl. Chem. 74, 857-867 (2002). 14. H. A. Barnes, J. Non-Newtonian Fluid Mech. 56, 221-251 (1995).
040005-8