Soft Matter ODES-Lab: Publications

Refereed Journal Publications

(*indicates corresponding author)

In preparation

41. Influence of Added Salt on Pinch-off Dynamics and Extensional Rheology Response of Polyelectrolytes Solutions Characterized using Dripping-onto-Substrate rheometry, L.N, Jimenez, J. Dinic and V.Sharma, in preparation.

40. Tears of Wine, P. Rathore, C. Xu and V. Sharma*, in preparation.

39. Lifespan of Viscoelastic Filaments, J. Dinic and V. Sharma*,  in preparation

38. Micellar Structure and Stratification in Free Standing Films of Aqueous Sodium Naphthenate Solutions, S. Guo, C. Ochoa, V. Sharma, and S. Srivastava*, in preparation.

37. Stratification and Micellar Interactions in Free Standing Films of Sodium Naphthenate Solutions, C. Ochoa, S. Guo, W. Yang. Y. Zhang, S. Srivastava and V. Sharma*, in preparation.

36. Micellar Structure/Interactions and Stratification in Free Standing Films of Micellar Ionic Surfactant Solutions, C. Ochoa, S. Guo, S.Yilixiati, Y. Zhang, S. Srivastava and V. Sharma*, in preparation.

Under review/ revision

35. Extensional Rheology of Polymeric Coating Fluids, C. Martinez, J. Dinic, M. Egeler#, D. Rich, P. Chevalier, J. DeGroot and V. Sharma*, under review (submitted Feb. 2019)

34. Domain Expansion Dynamics and Ridge Evolution in Stratifying Micellar Films: Theory, Y. Zhang and V. Sharma*, Under revision (submitted Jan 2019).

33. Nanoscopic Topography and Stratification in Micellar Films of Bile Salts, S.Yilixiati, C. A. Uribe Ortiz and V. Sharma*, Under revision (Submitted Dec 2018).

32. Macromolecular Dynamics, Extensional Rheology, Pinch-off Dynamics, and Printability of Aqueous Solutions of Flexible and Semi-Flexible Polymers, J. Dinic and V. Sharma*, Under Revision (Submitted Nov. 2018).

Published/ In press

31. Macromolecular Relaxation, Strain and Extensibility Determine Elastocapillary Thinning and Extensional Viscosity of Polymer Solutions, J. Dinic and V. Sharma*, Proceedings of the National Academy of Sciences, Accepted (2019).

30. Spinodal Stratification in Ultrathin Micellar Foam Films, S. Yilixiati, E. Wojcik#, Y. Zhang and V. Sharma*,  Molecular Systems Design & Engineering, In press (2019)

29. Bird of Transport, (Poem, published as an Editorial), Vivek Sharma*, Physics of Fluids, 2, 020902 (2019).

28. Effect of Salt Valency and Concentration on Shear and Extensional Rheology of Aqueous Polyelectrolyte Solutions for Enhanced Oil Recovery, A.V. Walter, L. N. Jimenez, J. Dinic, V. Sharma and K.A. Erk*, Rheological Acta (2018).



27. Computational Analysis of Self-Similar Capillary-Driven Thinning and Pinch-off Dynamics during Dripping using Volume-of-Fluids  Method, J. Dinic, and V. Sharma*, Physics of Fluids.,  (2019). ComputationalAnalysisofPinchOffFlow3DDripping

26. Extensional Relaxation Time, Pinch-off Dynamics and Printability of Semi-Dilute Polyelectrolyte Solutions, L. N. Jimenez, J. Dinic, N. Parsi and V. Sharma*, Macromolecules, 51, 5191-5208 (2018). ExtensionalRheologySaltfreeSemidilutePolyelectrolyteSolutions

25. Thickness-dependent Phase Transition Drives Nanoridge-to-Mesa Instability in Micellar Freestanding Films, Y. Zhang and V. Sharma*, Langmuir34 (26), 7922-7931(2018) PDF_Nanoridge-to-mesaInstabilityStratifiedFilms

Understanding fluxes and instabilities within freestanding ultrathin films is necessary for a better understanding of, and control over, the stability and lifetime of foams and emulsions. In micellar foam films, confinement-induced layering of micelles leads to stepwise thinning or stratification that occurs by the expansion of thinner, darker domains. Often, because of a nanoridge-to-mesa instability, one or more brighter white spots or “mesas” appear at the circular moving front between thinner domains and the thicker (less dark) surrounding film. Previous studies assume that the instability and the appearance of white spots are similar to the capillarity-driven Rayleigh instability that leads to the breakup of a coherent liquid jet. Using the IDIOM (interferometry digital imaging optical microscopy) protocols we recently developed, we characterize the nanoridge-to-mesa instability with exquisite spatiotemporal resolution (thickness <1 nm, time <1 ms). The instability could be classified as a Rayleigh instability if a similar sequence of thick and thin undulations is visualized around the expanding domains. However, quantitative analysis reveals that only mesas grow in size after the instability, whereas the rest of the nanoridge preserves its shape. By analogy to the phase separation into compositionally distinct regions, we show that the spontaneous nucleation of thicker mesas in stratifying films is a phase transition driven by the oscillatory nature of the free-energy functional.

24. “Passive Nonlinear Microrheology for Determining Extensional Rheology”, K. W. Hsiao, J. Dinic, Y. Ren, V. Sharma and C. M. Schroeder*, Phys. Fluids, 29, 121603 (2017). Microrheology PDF

23. “Influence of Salt on Supramolecular Oscillatory Structural Forces and Stratification in Micellar Foam Films, ”, S. Yilixiati, R. Rafiq, Y. Zhang and V. Sharma*, ACS Nano, 12,  1050-1061 (2018). Effect of Salt on Stratification PDF

Freestanding films of soft matter containing micelles, nanoparticles, polyelectrolyte−surfactant complexes, bilayers, and smectic liquid crystals exhibit stratification. Stepwise thinning and coexisting thick−thin regions associated with drainage via stratification are attributed to the confinement-induced structuring and layering of supramolecular structures, which contribute supramolecular oscillatory structural forces. In this contribution, we elucidate how the addition of salt affects stepwise thinning: step size, number of steps, as well as the shape and size of nanoscopic nonflat structures such as mesas in micellar foam films formed with aqueous solutions of anionic surfactant (sodium dodecyl sulfate (SDS)). The nanoscopic thickness variations and transitions are visualized and analyzed using IDIOM (Interferometry Digital Imaging Optical Microscopy) protocols with exquisite spatiotemporal resolution (thickness ∼1 nm, time <1 ms). In contrast to nanoparticle dispersions that show no influence of salt on step size, we find that the addition of salt to micellar freestanding films results in a decrease in step size as well as the number of stepwise transitions, in addition to changes in nucleation and growth of mesas, all driven by the corresponding change in supramolecular oscillatory structural forces.

22. “Pinch-off Dynamics and Extensional Relaxation Times of Intrinsically Semi-Dilute Polymer Solutions Characterized by Dripping-onto-Substrate (DoS) Rheometry”, J. Dinic, M. Biagioli and V. Sharma*, J. Polymer Sci. Polym. Phys., 55, 1692-1704 (2017). DOI: 10.1002/polb.24388 PDF
Stream-wise velocity-gradients associated with extensional flows arise in thinning liquid necks spontaneously formed during jetting, printing, coating, spraying, atomization, and microfluidic-based drop formation. In this contribution, we employ Dripping-onto-Substrate (DoS) rheometry protocols to measure the extensional rheology response of intrinsically semi-dilute polymer solutions by visualizing and analyzing capillary-driven thinning of a columnar neck formed between a nozzle and a sessile drop. We show that extensional viscosity that quantifies the resistance to stream-wise velocity gradients is orders of magnitude higher than the shear viscosity. Although shear flows only weakly perturb the chain dimensions, extensional flows can strongly stretch and orient the chains, thus influencing both intra- and inter-chain interactions. We find that the extensional relaxation times for intrinsically semi-dilute PEO solutions in a good solvent for five different molecular weights increase linearly with concentration, exhibiting a stronger concentration dependence than observed for dilute solutions, or anticipated by blob models, developed for relaxation of weakly perturbed chains in a good solvent.

21.“Nanoridge Formation and Dynamics of Stratification in Micellar Freestanding Films ”, Y. Zhang and V. Sharma*, Langmuir, 34(3),  1208-1217 (2018). Nanoridge PDF

Freestanding films (thickness <100 nm), stabilized by surfactants above the critical micelle concentration, exhibit stratification or stepwise thinning. Stratification proceeds by formation of thinner domains that grow at the expense of surrounding films. In this Article, we address several longstanding challenges related to the experimental characterization and theoretical description of thickness variations, forces, fluxes and flows underlying stratification. We show that nanoridges form and grow at the moving front around expanding domains, and we visualize their shape evolution using Interferometry Digital Imaging Optical Microscopy (IDIOM) protocols with an unprecedented spatiotemporal resolution (thickness <10 nm, time <1 ms). We develop a theoretical model for drainage via stratification under the influence of supramolecular oscillatory surface forces arising from the confinement-induced layering of micelles, and we show that the nanoridge growth and domain expansion dynamics can be modeled quantitatively.

20. “Pinch-off Dynamics and Dripping-onto-Substrate (DoS) Rheometry of Complex Fluids”, J. Dinic, L. N. Jimenez and V. Sharma*, Lab Chip, 17, 460-473, 2017. DoS Rheometry PDF
Characterization of pinch-off dynamics and the response to both shear and extensional flows that influence drop formation/deposition in microfluidic and printing applications requires bespoke instrumentation not available, or easily replicated, in most laboratories. Here we show that dripping-onto-substrate (DoS) rheometry protocols that involve visualization and analysis of capillary-driven thinning and pinch-off dynamics of a columnar neck formed between a nozzle and a sessile drop can be used for measuring shear viscosity, power law index, extensional viscosity, relaxation time and the most relevant processing timescale for printing. We showcase the versatility of DoS rheometry by characterizing and contrasting the pinch-off dynamics of a wide spectrum of simple and complex fluids: water, printing inks, semi-dilute polymer solutions, yield stress fluids, food materials and cosmetics. We show that DoS rheometry enables characterization of low viscosity printing inks and polymer solutions that are beyond the measurable range of commercially-available capillary break-up extensional rheometer (CaBER). We show that for high viscosity fluids, DoS rheometry can be implemented relatively inexpensively using an off-the-shelf digital camera, and for many complex fluids, similar power law scaling exponent describes both neck thinning dynamics and the shear thinning response.

19.“Nanoscopic Terraces, Mesas, and Ridges in Freely Standing Thin Films Sculpted by Supramolecular Oscillatory Surface Forces ”, Y. Zhang, S. Yilixiati, C. Pearsall and V. Sharma*ACS Nano10, 4678-4683 (2016). IDIOM PDF

Understanding and characterizing the spontaneous creation and evolution of nanoscopic topography of stratifying, freely standing thin liquid films have been long-standing challenges due to the absence of experimental techniques with the requisite spatial (thickness <10 nm) and temporal resolution (<1 ms). Using Interferometry Digital Imaging Optical Microscopy (IDIOM) protocols developed herein, we visualize and characterize size, shape, and evolution kinetics of nanoscopic mesas, terraces, and ridges.

18. “Extensional Relaxation Times of Dilute Polymer Solutions”, J. Dinic, Y. Zhang, L. N. Jimenez and V. Sharma*, ACS Macro Lett., DoS Rheometry-Dilute Solutions PDF

We show that visualization and analysis of capillary-driven thinning and pinch-off dynamics of the columnar neck in an asymmetric liquid bridge created by dripping-onto-substrate can be used for characterizing the extensional rheology of complex fluids. As the radius of the neck that connects a sessile drop to a nozzle is detected optically, and the extensional response for viscoelastic fluids is characterized by analyzing their elastocapillary self-thinning, we refer to this technique as optically-detected elastocapillary self-thinning dripping-onto-substrate (ODES-DOS) extensional rheometry.

17.“Domain expansion kinetics in stratifying foam films: Experiments”, Y. Zhang and V. Sharma*Soft Matter.11, 4408-4417 (2015). PDF_DomainExpansionKineticsExperiments

Domain and associated thickness variation in foam films made from sodium dodecyl sulfate (SDS) micellar solutions are examined using a Scheludko-type cell with a novel technique we call Interferometry Digital Imaging Optical Microscopy (IDIOM). We show that the domain expansion dynamics exhibit two distinct growth regimes with characteristic scaling laws.

16. “The Rheology of Aqueous Solutions of Ethyl Hydroxy-Ethyl Cellulose (EHEC) and its Hydrophobically Modified Analogue (hmEHEC): Extensional Flow Response in Capillary Breakup, Jetting (ROJER) and in a Cross-Slot Extensional Rheometer”, V. Sharma*, S.J. Haward, J. Serdy, B. Keshavarz, A. Söderlund, P.Threlfall-Holmes and G. H. McKinley, Soft Matter, 11, 3251-3270 (2015). ROJER PDF


    1. Studying the Effects of Elongational Properties on Atomization of Weakly Viscoelastic Solutions Using Rayleigh Ohnesorge Jetting Extensional Rheometry (ROJER),” B. Keshavarz, V. Sharma, E. C. Houze, M. R. Koerner, J. R. Moore, P. M. Cotts, P. Threlfall-Holmes and G. H. McKinley, JNNFM, 2015.

    2. “Bouligand structures underlie circularly polarized iridescence of scarab beetles: a closer view,” V. Sharma, M. Crne, J. O. Park and M. Srinivasarao, Materials Today: Proceedings, 1S, 161-171, (2014). Bouligand Patterns PDF 


Published before 2013

  1. “An intriguing empirical rule for estimating the first normal stress difference from steady shear viscosity data for polymer solutions and melts,” V. Sharma* and G. H. McKinley, Rheologica Acta, 51 (6), 487-495 (2012) Abnormal Rule PDF

  2. “Shear and extensional rheology of cellulose in ionic liquids”, S. J. Haward*, V. Sharma, G. H. McKinley and S. Rahatekar, Biomacromolecules, 13, 1688-1699 (2012). Cellulose/Ionic Liquids PDF

11.  “Rheology of Globular Proteins: Apparent yield stress, interfacial viscosity and high shear rate viscosity of Bovine Serum Albumin Solutions,” V. Sharma, A. Jaishankar, Y. Wang and G. H. McKinley*, Soft Matter, 7 (11), 5150-5160 (2011). Protein Rheology PDF

  1. “Mimicry of Papilio Palinurus Butterfly Optical Effects,” M. Crne, V. Sharma, J. Blair, J. O. Park, C. J. Summers and M. Srinivasarao*, EPL, 93 (1), 14001 (2011) PDF Papilio Biomimicry

  2. “Extensional opto-rheometry with biofluids and ultra-dilute polymer solutions”, S.J. Haward, V. Sharma and J. A. Odell, Soft Matter, 7 (21), 9908-9921 (2011). Cover Art PDF Extensional Opto-Rheometry

  3. “Apparent bulk yield stress, interfacial creep ringing and interfacial viscoelasticity of globular protein/surfactant mixtures,” A. Jaishankar, V. Sharma and G. H. McKinley, Soft Matter, 7 (17), 7623-7634 (2011). PDF Protein-Surfactant Interfacial Rheology & Creep Ringing

  4. “Characterization of ordered arrays of micropores in a polymer film,” L. Song, V. Sharma, J. O. Park and M. Srinivasarao, Soft Matter, 7, 1890-1896 (2011) PDF Ordered Arrays Breath Figure Templated Assembly

  5. “Effect of solvent choice on breath-figure-templated assembly of ‘holey’ polymer films,” V. Sharma, L. Song, R. L. Jones, P. R. Williams and M. Srinivasarao, EPL, 91, 38001 (2010). PDF

  6. “Dynamics of bead formation, filament thinning and breakup in weakly viscoelastic jets,” A. M. Ardekani, V. Sharma and G. H. McKinley, J. Fluid Mech., 665, 46-56 (2010) PDF

  1. “Structural Origin of Circularly Polarized Iridescence in Jeweled Beetles,” V. Sharma, M. Crne, J. O. Park and M. Srinivasarao, Science, 325, 449-452 (2009). Jewel Beetles PDF  

Research featured in

  1.  “Colloidal dispersion of gold nanorods: Historical background, optical properties, synthesis, separation and self-assembly,” Material Science and Engineering Reports, 65, 1-38 (2009). GoldReview PDF         

    (published with Cover Image for the issue).

2. “Shape Separation of gold nanorods using centrifugation,” V. Sharma, K. Park and M. Srinivasarao, Proceedings of National Academy of Sciences, 106(13), 4981-4985 (2009). Shape Separation PDF           (Press Coverage, Analytical Chemistry News)

1. “Chaotic mixing in microdroplets,” R.O. Grigoriev, M.F. Schatz and V. Sharma, Lab Chip, 6, 1369-1372 (2006). Chaotic Mixing/Optomicrofluidics PDF