Individual DNA molecules in an ultradilute solution were observed with a fluorescence microscope as they flow between a scaled-down rotating roll and a stationary glass knife. The roll picks up a thin layer of liquid from a pool and drags it to the knife, establishing a bead delineated by two menisci. At low roll speed the flow is premetered and there is a large recirculation. The DNA experiences nearly rectilinear shear flow at the minimum gap position where there is a zero velocity surface. We report the mean and the distribution of fractional extension of DNA molecules and show that the mean fractional extension asymptotes to 0.5, in agreement with the results of Smith et al. [D. E. Smith et al., Science 283, 1724 (1999)]. Interestingly, no polymer distortion is observed at the two menisci. At high roll speed, capillarity is not strong enough to drive backflow; the big recirculation under the coverslip breaks into two smaller recirculations and two separation surfaces arise upstream and downstream of the location of the minimum gap. At the upstream separation surface, most DNA molecules are extended parallel to the knife as they traverse the field of view. We report the distribution of DNA extension and shape in this flow region. Slow, nodular recirculations are present under the upstream and downstream free surfaces. Notably, most DNA molecules stretch axially as they move in these slow recirculating regions.

1.
See EPAPS Document No. E-JORHD2-48-012404 for supplementary Figs. S1–S5.
This document may be retrieved via the EPAPS homepage (http://www.aip.org/pubservs/epaps.html) or from ftp.aip.org in the directory directory/epaps/. See the EPAPS homepage for more information.
2.
Adachi
,
K.
,
T.
Tamura
, and
R.
Nakamura
, “
Coating flow in a nip region and various critical phenomena
,”
AIChE J.
34
,
456
464
(
1988
).
3.
Astarita
,
G.
, “
Objective and generally applicable criteria for flow classification
,”
J. Non-Newtonian Fluid Mech.
6
,
69
76
(
1979
).
4.
Babcock
,
H. P.
,
R. E.
Teixeira
,
J. S.
Hur
,
E. S. G.
Shaqfeh
, and
S.
Chu
, “
Visualization of molecular fluctuations near the critical point of the coil-stretch transition in polymer elongation
,”
Macromolecules
36
,
4544
4548
(
2003
).
5.
Batchelor, G. K., An Introduction to Fluid Mechanics, 1st ed. (Cambridge University Press, New York, 1967).
6.
Bauman
,
T.
,
T.
Sullivan
, and
S.
Middleman
, “
Ribbing instability in coating flows—Effect of polymer additives
,”
Chem. Eng. Commun.
14
,
35
46
(
1982
).
7.
Carvalho, M. S., “Roll coating flows in rigid and deformable gaps,” Ph.D. thesis, University of Minnesota, Minneapolis, MN, 1996; available from UMI, Ann Arbor, MI, Order No. 9621887.
8.
Chopra
,
M.
,
L.
Li
,
H.
Hu
,
M. A.
Burns
, and
R. G.
Larson
, “
DNA molecular configurations in an evaporating droplet near a glass surface
,”
J. Rheol.
47
,
1111
1132
(
2003
).
9.
Coyle, D. J., “Knife and roll coating,” in Liquid Film Coating. Scientific Principles and their Technological Implications, edited by S. F. Kistler and P. M. Schweizer (Chapman and Hall, London, 1997), pp. 539–571.
10.
Coyle
,
D. J.
,
C. W.
Macosko
, and
L. E.
Scriven
, “
Film-splitting flows in forward roll coating
,”
J. Fluid Mech.
171
,
183
207
(
1986
).
11.
Coyle
,
D. J.
,
C. W.
Macosko
, and
L. E.
Scriven
, “
Stability of symmetric film-splitting between counterrotating cylinders
,”
J. Fluid Mech.
216
,
437
458
(
1990
).
12.
Dontula, P., “Polymer solutions in coating flows,” Ph.D. thesis, University of Minnesota, Minneapolis, MN, 1999; available from UMI, Ann Arbor, MI, Order No. 9937847.
13.
Flory, P. J., Principles of Polymer Chemistry, 1st ed. (Cornell University Press, Ithaca, NY, 1953).
14.
Fuller, G. G., Optical Rheometry of Complex Fluids (Oxford University Press, New York, 1995).
15.
Gaskell
,
P. H.
,
G. E.
Innes
, and
M. D.
Savage
, “
An experimental investigation of meniscus roll coating
,”
J. Fluid Mech.
355
,
17
44
(
1998
).
16.
Greener
,
Y.
, and
S.
Middleman
, “
A theory of roll coating of viscous and viscoelastic fluids
,”
Polym. Eng. Sci.
15
,
1
10
(
1975
).
17.
Greener
,
J.
,
T.
Sullivan
,
B.
Turner
, and
S.
Middleman
, “
Ribbing instability of a two-roll coater: Newtonian fluids
,”
Chem. Eng. Commun.
5
,
73
10
(
1980
).
18.
Haber
,
C.
,
S. A.
Ruiz
, and
D.
Wirtz
, “
Shape anisotropy of a single random-walk polymer
,”
Proc. Natl. Acad. Sci. U.S.A.
97
,
10792
10795
(
2000
).
19.
Hagerman
,
P. J.
, “
Flexibility of DNA
,”
Annu. Rev. Biophys. Biophys. Chem.
17
,
265
286
(
1988
).
20.
Harrison
,
G. M.
,
J.
Remmelgas
, and
L. G.
Leal
, “
The dynamics of ultradilute polymer solutions in transient flow: Comparison of dumbbell-based theory and experiment
,”
J. Rheol.
42
,
1039
1058
(
1998
).
21.
Haugland, R. P., Handbook of Fluorescent Probes and Research Chemicals, 6th ed. (Molecular Probes, Eugene, OR, 1996).
22.
Hur
,
J. S.
,
E. S. G.
Shaqfeh
, and
R. G.
Larson
, “
Brownian dynamics simulations of single DNA molecules in shear flow
,”
J. Rheol.
44
,
713
742
(
2000
).
23.
Hur
,
J. S.
,
E. S. G.
Shaqfeh
,
H. P.
Babcock
,
D. E.
Smith
, and
S.
Chu
, “
Dynamics of dilute and semidilute DNA solutions in the start-up of shear flow
,”
J. Rheol.
45
,
421
450
(
2001
).
24.
Janeschitz-Kriegl, H., Polymer Melt Rheology and Flow Birefringence (Springer, Berlin, 1983).
25.
Jendrejack
,
R. M.
,
J. J.
de Pablo
, and
M. D.
Graham
, “
Stochastic simulations of DNA in flow: Dynamics and the effects of hydrodynamic interaction
,”
J. Chem. Phys.
116
,
7752
7759
(
2002
).
26.
Jendrejack
,
R. M.
,
D. C.
Schwartz
,
J. J.
de Pablo
, and
M. D.
Graham
, “
Shear-induced migration in flowing polymer solutions: Simulation of long-chain DNA dynamics in microchannels
,”
J. Chem. Phys.
120
,
2513
2529
(
2004
).
27.
Jendrejack
,
R. M.
,
E. T.
Dimalanta
,
D. C.
Schwartz
,
M. D.
Graham
, and
J. J.
de Pablo
, “
DNA dynamics in a microchannel
,”
Phys. Rev. Lett.
91
,
038102
(
2003
).
28.
Kam
,
Z.
,
N.
Borochov
, and
H.
Eisenberg
, “
Dependence of laser light scattering of DNA on NaCl concentration
,”
Biopolymers
20
,
2671
2690
(
1981
).
29.
Larson
,
R. G.
,
H.
Hu
,
D. E.
Smith
, and
S.
Chu
, “
Brownian dynamics simulations of a DNA molecule in an extensional flow field
,”
J. Rheol.
43
,
267
304
(
1999
).
30.
Larson
,
R. G.
,
T. T.
Perkins
,
D. E.
Smith
, and
S.
Chu
, “
Hydrodynamics of a DNA molecule in a flow field
,”
Phys. Rev. E
55
,
1794
1797
(
1997
).
31.
Le Duc
,
P.
,
C.
Haber
,
G.
Bao
, and
D.
Wirtz
, “
Dynamics of individual flexible polymers in a shear flow
,”
Nature (London)
399
,
564
566
(
1999
).
32.
Morikawa
,
K.
, and
M.
Yanagida
, “
Visualization of individual DNA molecules in solution by light microscopy: DAPI staining method
,”
J. Biochem. (Tokyo)
89
,
693
696
(
1981
).
33.
Papanastasiou
,
T. C.
,
N.
Malamantaris
, and
K.
Ellwood
, “
A new outflow boundary condition
,”
Int. J. Numer. Methods Fluids
14
,
587
608
(
1992
).
34.
Pasquali, M., “Polymer molecules in free surface coating flows,” Ph.D. thesis, University of Minnesota, Minneapolis, MN, 2000; available from UMI, Ann Arbor, MI, Order No. 9963019.
35.
Pasquali
,
M.
, and
L. E.
Scriven
, “
Free surface flows of polymer solutions with models based on the conformation tensor
,”
J. Non-Newtonian Fluid Mech.
108
,
363
409
(
2002
).
36.
Perkins, T. T., “Exploring polymer dynamics with single DNA molecules,” Ph.D. thesis, Stanford University, Palo Alto, CA, 1997; available from UMI, Ann Arbor, MI, Order No. 9810187.
37.
Perkins
,
T. T.
,
D. E.
Smith
, and
S.
Chu
, “
Direct observation of tube-like motion of a single polymer chain
,”
Science
264
,
819
822
(
1994b
).
38.
Perkins
,
T. T.
,
D. E.
Smith
, and
S.
Chu
, “
Single polymer dynamics in an elongational flow
,”
Science
276
,
2016
2021
(
1997
).
39.
Perkins, T. T., D. E. Smith, and S. Chu, “Single polymers in elongational flows: Dynamic, steady-state and population averaged properties,” in Flexible Polymer Chain Dynamics in Elongational Flow: Theory and Experiment, edited by T. Q. Nguyen and H. H. Kausch (Springer, Berlin, 1999), pp. 283–334.
40.
Perkins
,
T. T.
,
S. R.
Quake
,
D. E.
Smith
, and
S.
Chu
, “
Relaxation of a single polymer molecule observed by optical microscopy
,”
Science
264
,
822
826
(
1994a
).
41.
Perkins
,
T. T.
,
D. E.
Smith
,
R. G.
Larson
, and
S.
Chu
, “
Stretching of a single tethered polymer in a uniform flow
,”
Science
268
,
83
87
(
1995
).
42.
Pitts
,
E.
, and
J.
Greiller
, “
The flow of thin liquid films between rollers
,”
J. Fluid Mech.
11
,
33
50
(
1961
).
43.
Savage
,
M. D.
, “
Cavitation in lubrication. Part 1. On boundary conditions and cavity–fluid interfaces
,”
J. Fluid Mech.
80
,
743
755
(
1977
).
44.
Savage
,
M. D.
, “
Mathematical model for the onset of ribbing
,”
AIChE J.
30
,
999
1002
(
1984
).
45.
Schunk
,
P. R.
, and
L. E.
Scriven
, “
Constitutive equation for modeling mixed extension and shear in polymer solution processing
,”
J. Rheol.
34
,
1085
1119
(
1990
).
46.
Shrewsbury, P. J., “Flow of complex biological macromolecules in microfluidic devices,” Ph.D. thesis, University of California, San Fransisco, CA and University of California, Berkeley, CA, 2000; available from UMI, Ann Arbor, MI, Order No. 9996538.
47.
Shrewsbury
,
P. J.
,
D.
Liepmann
, and
S. J.
Muller
, “
Concentration effects of a biopolymer in a microfluidic device
,”
Biomed. Microdevices
4
,
17
26
(
2002
).
48.
Shrewsbury
,
P. J.
,
S. J.
Muller
, and
D.
Liepmann
, “
Effect of flow on complex biological macromolecules in microfluidic devices
,”
Biomed. Microdevices
3
,
225
238
(
2001
).
49.
Smith, D. E., “Polymer physics experiments with single DNA molecules,” Ph.D. thesis, Stanford University, Palo Alto, CA, 1999; available from UMI, Ann Arbor, MI, Order No. 9943720.
50.
Smith
,
D. E.
, and
S.
Chu
, “
Response of flexible polymers to a sudden elongational flow
,”
Science
281
,
1335
1340
(
1998
).
51.
Smith
,
D. E.
,
H. P.
Babcock
, and
S.
Chu
, “
Single-polymer dynamics in steady shear flow
,”
Science
283
,
1724
1727
(
1999
).
52.
Torazzi, R., “Visualizzazione di singole molecole polimeriche in coating flows,” Master’s thesis (tesi di laurea), Università degli Studi di Bologna, Bologna, Italy, 1998.
53.
Wang
,
Y.
,
A.
Warshawsky
,
C.
Wang
,
N.
Kahana
,
C.
Chevallard
, and
V.
Steinberg
, “
Fluorescent ultrahigh-molecular-weight polyacrylamide probes for dynamic flow systems: Synthesis, conformational behavior and imaging
,”
Macromol. Chem. Phys.
203
,
1833
1843
(
2002
).
54.
Wilson
,
S. D. R.
, “
The drag-out problem in film coating theory
,”
J. Eng. Math.
16
,
209
221
(
1982
).
55.
Woo
,
N. J.
,
E. S. G.
Shaqfeh
, and
B.
Khomami
, “
The effect of confinement on dynamics and rheology of dilute deoxyribose nucleic acid solutions. II. Effective rheology and single chain dynamics
,”
J. Rheol.
48
,
299
318
(
2004a
).
56.
Woo
,
N. J.
,
E. S. G.
Shaqfeh
, and
B.
Khomami
, “
Effect of confinement on dynamics and rheology of dilute DNA solutions. I. Entropic spring force under confinement and a numerical algorithm
,”
J. Rheol.
48
,
281
298
(
2004b
).
57.
Yanagida
,
M.
,
I.
Hiroaka
, and
Y.
Katsura
, “
Dynamic behavior of DNA molecules in solution studied by fluorescence microscopy
,”
Cold Spring Harbor Symp. Quant. Biol.
47
,
177
187
(
1983
).
This content is only available via PDF.

Supplementary Material

You do not currently have access to this content.