OpTiDDM (Optical Tweezers integrating Differential Dynamic Microscopy) maps the spatiotemporal propagation of nonlinear stresses in polymer blends and composites

Abstract

How local stresses propagate through polymeric fluids, and, more generally, how macromolecular dynamics give rise to viscoelasticity are open questions vital to wide-ranging scientific and industrial fields. Here, to unambiguously connect polymer dynamics to force response, and map stress propagation in macromolecular materials, we present a powerful approach-Optical Tweezers integrating Differential Dynamic Microscopy (OpTiDMM)-that simultaneously imposes local strains, measures resistive forces, and analyzes the motion of the surrounding polymers. Our measurements with blends of ring and linear polymers (DNA) and their composites with stiff polymers (microtubules) uncover a surprising resonant response, in which affine alignment, superdiffusivity, and elastic memory are maximized when the strain rate is comparable to the entanglement rate. Microtubules suppress this resonance, while substantially increasing elastic force and memory, due to varying degrees to which the polymers buildup, stretch and flow along the strain path, and configurationally dissipate stress. More broadly, the rich multi-scale coupling of mechanics and dynamics afforded by OpTiDDM, empowers its interdisciplinary use to elucidate non-trivial phenomena that sculpt stress propagation dynamics-critical to commercial applications and cell mechanics alike.

32 pages, 10 figures

References in corpus (7)

• Differential Dynamic Microscopy: Probing wave vector dependent dynamics with a microscope
• Differential dynamic microscopy for the characterization of polymer systems
• Direct measurement of the intermolecular forces confining a single molecule in an entangled polymer solution
• Emergence of Multiscale Dynamics in Colloidal Gels
• Optical tweezers microrheology maps the dynamics of strain-induced local inhomogeneities in entangled polymers
• Dynamics and Rheology of Ring-Linear Blend Semidilute Solutions in Extensional Flow: Single Molecule Experiments
• Ring DNA confers enhanced bulk elasticity and restricted macromolecular diffusion in DNA-dextran blends

Cited by in corpus (4)

• Polymer threadings and rigidity dictate the viscoelasticity and nonlinear relaxation dynamics of entangled ring-linear blends and their composites with rigid rod microtubules
• Femtosecond laser-assisted selective holding with ultra-low power for direct manipulation of biological specimens
• Convolutional neural networks applied to differential dynamic microscopy reduces noise when quantifying heterogeneous dynamics
• Fluctuations of driven probes reveal nonequilibrium transitions in complex fluids