Charles E. Sing

For More Information

• Research Synopsis
• Research Group Website

Education

• Postdoctorate, Northwestern University, 2012-2014
• Ph.D., Massachusetts Institute of Technology, 2012
• M.S., Case Western Reserve University, 2008
• B.S.E., Case Western Reserve University, 2008

Biography

Charles E. Sing studies charged polymers, polymer dynamics, and biophysics. His research group seeks to use coarse-grained models to understand the emergent physics of polymer or biophysical systems, and then use the resulting insights to guide the design of new materials. Current research efforts are focused on problems that are challenging because they span large length and time scales, and new theory or simulation methods are necessary to yield new fundamental physical principles. Dr. Sing has been recognized with a number of honors, including the ACS PMSE Young Investigator Award (2020) and AIChE 35 Under 35 (2020). He received his BSE/MS from Case Western Reserve University and his Ph.D from the Massachusetts Institute of Technology. He completed his postdoctoral work at Northwestern University’s International Institute for Nanotechnology. He joined the department in 2014.

Research Statement

Research Statement:

Our research uses simulation and theory to understand polymer materials such as those in modern-day consumer products, advanced responsive or adaptive materials, and in biological systems. Our primary goal is to inform how polymers can be engineered at the molecular level, taking inspiration from biology where complex structure and function arises from processes occurring on disparate length and time scales. We integrate statistical mechanical theory and coarse-grained models to understand polymer physical phenomena, addressing fundamental physical problems using a unique brand of molecular engineering that combines accurate physicochemical models with first principles theory, in close collaboration with experimentalists. See below for a non-comprehensive list of research areas.

Charge-Driven Polymer Assembly

We are interested in how molecular details such as primary polymer sequence, macromolecular architecture, and electrostatic environment govern the thermodynamics and self-assembly of charged polymers. Our work probes the connections between molecular structure and thermodynamic phase behavior in complex coacervates, a class of charged polymer materials, using theory and simulation. Coacervates are broadly useful in applications ranging from personal care products to stimuli-responsive materials, and as analogues for biomolecular condensates. In this last application, we have made fundamental advances by studying the effect of charge sequence on assembly properties, and we seek to lay the foundations for designing polymers with built-in self-assembly instructions.

Out-of-Equilibrium Polymer Dynamics

We are interested in how hydrodynamics, polymer architecture, and intermolecular interactions influence the dynamics of polymers in solution. We have developed new computational methods for simulating out-of-equilibrium semidilute polymer solutions, in order to demonstrate how polymer architecture and hydrodynamic interactions govern the dynamics and structure of polymers in strong flows. Our research has revealed the importance of architecture-hydrodynamic coupling in flowing polymer solutions, and the presence of large conformational fluctuations driven by polymer-induced local flows in non-dilute systems. Much of this work has been in collaboration with Professor Schroeder, and will provide insights important to the solution processing of polymers, such as in printing or coating processes.

Brush-like Polymer Assembly

We are interested in how molecular architecture governs molecular interactions and assembly in polymer solutions. Our work has established models of architecture-mediated interactions in the solution behavior of highly-branched polymers. This includes coarse-graining procedures that allow us to simplify the structure of these brush-like macromolecules, while retaining key physical attributes and interactions. We use these advances in coarse-grained polymer models to explore the interplay between polymer branching and conformation, molecular interactions, and self-assembly in dense solutions. We collaborate with Profs. Diao, Rogers, and Guironnet on understanding the design of these systems for printing materials that exhibit structural color that is tunable ‘on-the-fly’ via processing conditions.

Research Interests

• Polymer Physics, Statistical Mechanics, and Computer Simulation

Selected Articles in Journals

• Lytle, T.K.; Sing, C.E. "Transfer matrix theory of polymer complex coacervation." Soft Matter 2017 13 7001-7012.
•  Lytle, T.K.; Radhakrishna, M.; Sing, C.E. "High charge density coacervate assembly via hybrid Monte Carlo single chain in mean field theory." Macromolecules 2016 49 9693-9705.
•  Hsiao, K.W.; Schroeder, C.M.; Sing, C.E. "Ring polymer dynamics are governed by a coupling between architecture and hydrodynamic interactions." Macromolecules 2016 49 1961-1971.
•  Radhakrishna, M.; Sing, C.E. "Charge correlations for precise, coulombically driven self assembly." Macromol. Chem. Phys. 2016 217 126-136.
• Perry, S.L.; Sing, C.E. "PRISM-based Theory of Complex Coacervation: Excluded Volume versus Chain Correlation." Macromolecules 2015 48 5040-5053.
• Sing, C.E.; Zwanikken, J.W.; Olvera de la Cruz, M. "Theory of melt polyelectrolyte blends and block copolymers: Phase behavior, surface tension, and microphase periodicity." J. Chem. Phys. 2015 14 034902.
• Sing, C.E.; Olvera de la Cruz, M. "Polyelectrolyte blends and non-trivial behavior in effective Flory-Huggins parameters." ACS Macro Lett. 20143 698-702.
• Sing, C.E.; Zwanikken, J.W.; Olvera de la Cruz, M.; "Electrostatic control of block copolymer morphology." Nat. Mater. 2014 13 694-698.
• Mai, D.J.; Marciel, A.B.; Sing, C.E.; Schroeder, C.M. "Topology-Controlled Relaxation Dynamics of Single Branched Polymers." ACS Macro Lett. 2015 4 446-452.
• Sing, C.E.; Olvera de la Cruz, M.; Marko, J.F. "Multiple-binding-site mechanism explains concentration-dependent unbinding rates of DNA-binding proteins." Nuc. Acids Res. 2013 42 3783-3791.
• Sing, C.E.; Zwanikken, J.W.; Olvera de la Cruz, M.; "Interfacial behavior in polyelectrolyte blends: hybrid liquid-state integral equation and self-consistent field theory study." Phys. Rev. Lett. 2013 111 168303.
• Sing, C.E.; Zwanikken, J.W.; Olvera de la Cruz, M.; "Correlation-induced phase separation in polyelectrolyte blends." ACS Macro Letters. 2013 2 1042-1046.
• Sing, C.E.; Alexander-Katz, A.; "Von Willlebrand Adhesion to Surfaces at High Shear Rates is Controlled by Long-Lived Bonds." Biophys. J. 2013 105,1475-1481.
• Sing, C.E.; Zwanikken, J.W.; Olvera de la Cruz, M.; "Effect of Ion-Ion Correlations on Polyelectrolyte Gel Collapse and Reentrant Swelling." Macromolecules. 2013 46, 5053-5065.
• Sing, C.E.; Alexander-Katz, A.; “Force Spectroscopy of Self-Associating Homopolymers” Macromolecules 2012 45(16), 6704-6718.
• Sing, C.E.; Alexander-Katz, A.; “Designed Molecular Mechanics Using Self-associating Polymer Components” Soft Matter 2012 8, 11871-11879.
• Sing, C.E.; Einert, T.A.; Netz, R.R.; Alexander-Katz, A.; “Probing Structural Transitions in Polymer Globules by Force.” Phys. Rev. E 2011 83(4), 040801(R).
• Sing, C.E.; Alexander-Katz, A.; “Collapsed polymer behavior in combinations of shear and elongational flow fields.” J. Chem. Phys. 2011 135, 014902.
• Sing, C.E.; Alexander-Katz, A.; “Theory of tethered polymers in shear flow: the strong stretching limit.” Macromolecules 2011 44(22), 9020-9028.
• Sing, C.E.; Alexander-Katz, A.; “Giant non-monotonic stretching response of a self-associating polymer in shear flow” Phys. Rev. Lett. 2011 107, 198302.
• Sing, C.E.; Alexander-Katz, A.; “Equilibrium Structure and Dynamics of Self-Associating Single Polymers” Macromolecules 2011 44(17), 6962-6971.
• Sing, C.E.; Alexander-Katz, A.; “Non-monotonic lift forces on stretched polymers near surfaces.” EPL 2011 95, 48001.
• Einert, T.A.; Sing, C.E.; Alexander-Katz, A.; Netz, R.R.; “Internal Friction of Homo-polymeric Systems Studied by Diffusion and Non-equilibrium Unfolding of Globules.” Eur. Phys. J. E. 2011 34, 130.
• Sing, C.E.; Schmid, L.; Schneider, M.; Franke, T.; Alexander-Katz, A.; “Self-assembled colloidal walkers: from single chain motion to controlled surface-induced flows.” Proc. Natl. Acad. Sci. U.S.A. 2010 107(2), 535-540.
• Sing, C.E.; Alexander-Katz, A.; “Globule-stretch transitions of collapsed polymers in elongational flow fields.” Macromolecules 2010 43(7), 3532-3541.
• Sing, C.E.; Alexander-Katz, A.; “Elongational flow induces the unfolding of von Willebrand Factor at physiological flow rates.” Biophys. J.  2010 98(9), L35- L37.
• Sing, C.E.; Kunzelman, J.; Weder, C.; “Time-temperature indicators for high temperature applications.” J. Mat. Chem. 2009, 19(1), 104-110.
• Crenshaw, B.; Kunzelman, J.; Sing, C.E.; Ander, C.; Weder, C.; “Threshold Temperature Sensors with Tunable Properties.” Macromol. Chem. Phys. 2007, 208, 572-580.

Honors

• Helen Corley Petit Scholar (2020)
• AIChE 35 Under 35 (2020)
• ACS PMSE Young Investigator (2020)
• U.S. Frontiers of Engineering, NAE (2018)
• NSF CAREER Award (2017)
• Forbes 30 Under 30 for Science (2015)
• College of Engineering Academy of Excellence in Engineering Education, Collins Scholar (2014-2015)
• MIT DMSE Best PhD Thesis Award (2013)
• International Institute for Nanotechnology Postdoctoral Fellowship (2012)
• National Defense Science and Engineering Graduate Fellowship (2009-2012)
• MIT/Dupont Alliance Presidential Fellowship (2008)

Teaching Honors

• School of Chemical Sciences Excellence in Teaching Award (2017-2018)
• MIT DMSE Graduate Student Teaching Award (2012)