Stanford Advisors

Contact

  • Academic
    jakesong@stanford.edu
    University - Scholar Department: Mechanical Engineering Position: Postdoctoral Scholar

Additional Info

  • Mail Code: 3030

All Publications

  • Non-linear rheology of melted cheddar cheese JOURNAL OF FOOD ENGINEERING Song, J. 2025; 391

    View details for DOI 10.1016/j.jfoodeng.2024.112450

    View details for Web of Science ID 001424252800001

  • Valence can control the nonexponential viscoelastic relaxation of multivalent reversible gels. Science advances Le Roy, H., Song, J., Lundberg, D., Zhukhovitskiy, A. V., Johnson, J. A., McKinley, G. H., Holten-Andersen, N., Lenz, M. 2024; 10 (20): eadl5056

    Abstract

    Gels made of telechelic polymers connected by reversible cross-linkers are a versatile design platform for biocompatible viscoelastic materials. Their linear response to a step strain displays a fast, near-exponential relaxation when using low-valence cross-linkers, while larger supramolecular cross-linkers bring about much slower dynamics involving a wide distribution of timescales whose physical origin is still debated. Here, we propose a model where the relaxation of polymer gels in the dilute regime originates from elementary events in which the bonds connecting two neighboring cross-linkers all disconnect. Larger cross-linkers allow for a greater average number of bonds connecting them but also generate more heterogeneity. We characterize the resulting distribution of relaxation timescales analytically and accurately reproduce stress relaxation measurements on metal-coordinated hydrogels with a variety of cross-linker sizes including ions, metal-organic cages, and nanoparticles. Our approach is simple enough to be extended to any cross-linker size and could thus be harnessed for the rational design of complex viscoelastic materials.

    View details for DOI 10.1126/sciadv.adl5056

    View details for PubMedID 38748785

    View details for PubMedCentralID PMC11095449

  • Soft Viscoelastic Magnetic Hydrogels from the In Situ Mineralization of Iron Oxide in Metal-Coordinate Polymer Networks ACS APPLIED MATERIALS & INTERFACES Song, J., Kim, S., Saouaf, O., Owens, C., McKinley, G. H., Holten-Andersen, N. 2023; 15 (45): 52874-52882

    Abstract

    The design of soft magnetic hydrogels with high concentrations of magnetic particles is complicated by weak retention of the iron oxide particles in the hydrogel scaffold. Here, we propose a design strategy that circumvents this problem through the in situ mineralization of iron oxide nanoparticles within polymer hydrogels functionalized with strongly iron-coordinating nitrocatechol groups. The mineralization process facilitates the synthesis of a high concentration of large iron oxide nanoparticles (up to 57 wt % dry mass per single cycle) in a simple one-step process under ambient conditions. The resulting hydrogels are soft (kPa range) and viscoelastic and exhibit strong magnetic actuation. This strategy offers a pathway for the energy-efficient design of soft, mechanically robust, and magneto-responsive hydrogels for biomedical applications.

    View details for DOI 10.1021/acsami.3c08145

    View details for Web of Science ID 001105576100001

    View details for PubMedID 37916735

    View details for PubMedCentralID PMC10658456

  • Non-Maxwellian viscoelastic stress relaxations in soft matter. Soft matter Song, J., Holten-Andersen, N., McKinley, G. H. 2023

    Abstract

    Viscoelastic stress relaxation is a basic characteristic of soft matter systems such as colloids, gels, and biological networks. Although the Maxwell model of linear viscoelasticity provides a classical description of stress relaxation, it is often not sufficient for capturing the complex relaxation dynamics of soft matter. In this Tutorial, we introduce and discuss the physics of non-Maxwellian linear stress relaxation as observed in soft materials, the ascribed origins of this effect in different systems, and appropriate models that can be used to capture this relaxation behavior. We provide a basic toolkit that can assist the understanding and modeling of the mechanical relaxation of soft materials for diverse applications.

    View details for DOI 10.1039/d3sm00736g

    View details for PubMedID 37846782

  • Non-Maxwellian viscoelastic stress relaxations in soft matter SOFT MATTER Song, J., Holten-Andersen, N., Mckinley, G. H. 2023

    View details for DOI 10.1039/d3sm00736

    View details for Web of Science ID 001083444500001