Michael Burroughs

All Publications

• Flow-concentration coupling determines features of nonhomogeneous flow and shear banding in entangled polymer solutions JOURNAL OF RHEOLOGY Burroughs, M. C., Zhang, Y., Shetty, A., Bates, C. M., Helgeson, M. E., Leal, L. 2023; 67 (1): 219-239

  View details for DOI 10.1122/8.0000469

  View details for Web of Science ID 000886614800001

• Flow-Induced Concentration Nonuniformity and Shear Banding in Entangled Polymer Solutions PHYSICAL REVIEW LETTERS Burroughs, M. C., Zhang, Y., Shetty, A. M., Bates, C. M., Leal, L., Helgeson, M. E. 2021; 126 (20): 207801

  Abstract

  Recent models have predicted entangled polymer solutions could shear band due to unstable flow-induced demixing. This work provides the first experimental probe of the in situ concentration profile of entangled polymer solutions under shear. At shear rates above a critical value, we show that the concentration and velocity profiles can develop bands, in quantitative agreement with steady-state model predictions. These findings highlight the critical importance of flow-concentration coupling in entangled polymer solutions.

  View details for DOI 10.1103/PhysRevLett.126.207801

  View details for Web of Science ID 000652840600012

  View details for PubMedID 34110187

• Cellulose nanocrystals for gelation and percolation-induced reinforcement of a photocurable poly(vinyl alcohol) derivative SOFT MATTER Corder, R. D., Adhikari, P., Burroughs, M. C., Rojas, O. J., Khan, S. A. 2020; 16 (37): 8602-8611

  Abstract

  Nanomaterials are regularly added to crosslinkable polymers to enhance mechanical properties; however, important effects related to gelation behavior and crosslinking kinetics are often overlooked. In this study, we combine cellulose nanocrystals (CNCs) with a photoactive poly(vinyl alcohol) derivative, PVA-SbQ, to form photocrosslinked nanocomposite hydrogels. We investigate the rheology of PVA-SbQ with and without CNCs to decipher the role of each component in final property development and identify a critical CNC concentration (1.5 wt%) above which several changes in rheological behavior are observed. Neat PVA-SbQ solutions exhibit Newtonian flow behavior across all concentrations, while CNC dispersions are shear-thinning <6 wt% and gel at high concentrations. Combining semi-dilute entangled PVA-SbQ (6 wt%) with >1.5 wt% CNCs forms a percolated microstructure. In situ photocrosslinking experiments reveal how CNCs affect both the gelation kinetics and storage modulus (G') of the resulting hydrogels. The modulus crossover time increases after addition of up to 1.5 wt% CNCs, while no modulus crossover is observed >1.5 wt% CNCs. A sharp increase in G' is observed >1.5 wt% CNCs for fully-crosslinked networks due to favorable PVA-SbQ/CNC interactions. A percolation model is fitted to the G' data to confirm that mechanical percolation is maintained after photocrosslinking. A ∼120% increase in G' for 2.5 wt% CNCs (relative to neat PVA-SbQ) confirms that CNCs provide a reinforcing effect through the percolated microstructure formed from PVA-SbQ/CNC interactions. The results are testament to the ability of CNCs to significantly alter the storage moduli of crosslinked polymer gels at low loading fractions through percolation-induced reinforcement.

  View details for DOI 10.1039/d0sm01376e

  View details for Web of Science ID 000573714400003

  View details for PubMedID 32845269

• Coupled nonhomogeneous flows and flow-enhanced concentration fluctuations during startup shear of entangled polymer solutions PHYSICAL REVIEW FLUIDS Burroughs, M. C., Shetty, A. M., Leal, L., Helgeson, M. E. 2020; 5 (4)

  View details for DOI 10.1103/PhysRevFluids.5.043301

  View details for Web of Science ID 000528783500003

• Distinguishing shear banding from shear thinning in flows with a shear stress gradient RHEOLOGICA ACTA Cheng, P., Burroughs, M. C., Leal, L., Helgeson, M. E. 2017; 56 (12): 1007-1032

  View details for DOI 10.1007/s00397-017-1051-y

  View details for Web of Science ID 000415094000005

• Cooperative Assembly of Metal Nitrate and Citric Acid with Block Copolymers: Role of Carbonate Conversion Temperature on the Mesostructure of Ordered Porous Oxides JOURNAL OF PHYSICAL CHEMISTRY C Burroughs, M. C., Bhaway, S. M., Tangvijitsakul, P., Cavicchi, K. A., Soucek, M. D., Vogt, B. D. 2015; 119 (22): 12138-12148

  View details for DOI 10.1021/acs.jpcc.5b02177

  View details for Web of Science ID 000355891600005

• Cyclodextrin facilitated electrospun chitosan nanofibers RSC ADVANCES Burns, N. A., Burroughs, M. C., Gracz, H., Pritchard, C. Q., Brozena, A. H., Willoughby, J., Khan, S. A. 2015; 5 (10): 7131-7137

  View details for DOI 10.1039/c4ra09662b

  View details for Web of Science ID 000347609400015