Viscoelastic properties of ring-linear DNA blends exhibit non-monotonic dependence on blend composition

Abstract

Entangled ring polymers, along with blends of ring and linear polymers, continue to be a topic of great interest and debate due to the conflicting experimental results in the literature as well as the difficulty of producing entangled synthetic rings devoid of linear contaminants. Here, we create blended solutions of entangled ring and linear DNA with varying mass fractions of linear DNA. We use optical tweezers microrheology to measure the linear and nonlinear viscoelastic response of these blends. Our measurements reveal a strong non-monotonic dependence of linear viscoelastic properties on linear DNA fraction, with a pronounced maximum when the mass fraction of rings and linear chains are comparable, suggestive of pervasive threading of rings by linear chains. We observe a similar non-monotonicity in the nonlinear regime; however, a comparatively higher fraction of linear chains (0.5-0.7) is required for a substantial increase in resisitive force and slowing of relaxation dynamics to emerge. This nonlinear response also appears to be rate dependent, which we argue arises from force-induced de-threading of rings at high strain rates. Our results fill a longstanding gap in knowledge regarding the microrheology and nonlinear response of ring-linear polymer blends. Moreover, the uniquely strong mechanical response that ring-linear blends exhibit, along with the ability to finely tune these blends by varying the blend composition, provides new materials design principles.

arXiv comment16 pages, 4 Figures

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Cited by in corpus (6)

• Composite Entanglement Topology and Extensional Rheology of Symmetric Ring-Linear Polymer Blends
• Dynamics and Rheology of Ring-Linear Blend Semidilute Solutions in Extensional Flow: Single Molecule Experiments
• OpTiDDM (Optical Tweezers integrating Differential Dynamic Microscopy) maps the spatiotemporal propagation of nonlinear stresses in polymer blends and composites
• Active restructuring of cytoskeleton composites leads to increased mechanical stiffness, memory, and heterogeneity
• Polymer threadings and rigidity dictate the viscoelasticity and nonlinear relaxation dynamics of entangled ring-linear blends and their composites with rigid rod microtubules
• Topological digestion drives time-varying rheology of entangled DNA fluids