Nava Giovanni, Rossi Marina, Biffi Silvia, Sciortino Francesco, Bellini Tommaso
Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, via Fratelli Cervi 93, I-20090 Segrate, Milano, Italy.
Department of Physics and CNR-ISC, Sapienza Università di Roma, Piazzale Aldo Moro 2, I-00185 Roma, Italy.
Phys Rev Lett. 2017 Aug 18;119(7):078002. doi: 10.1103/PhysRevLett.119.078002. Epub 2017 Aug 16.
Transient molecular networks, a class of adaptive soft materials with remarkable application potential, display complex, and intriguing dynamic behavior. By performing dynamic light scattering on a wide angular range, we study the relaxation dynamics of a reversible network formed by DNA tetravalent nanoparticles, finding a slow relaxation mode that is wave vector independent at large q and crosses over to a standard q^{-2} viscoelastic relaxation at low q. Exploiting the controlled properties of our DNA network, we attribute this mode to fluctuations in local elasticity induced by connectivity rearrangement. We propose a simple beads and springs model that captures the basic features of this q^{0} behavior.
瞬态分子网络是一类具有显著应用潜力的自适应软材料，展现出复杂且引人入胜的动态行为。通过在宽角度范围内进行动态光散射，我们研究了由DNA四价纳米颗粒形成的可逆网络的弛豫动力学，发现一种慢弛豫模式，该模式在大q值时与波矢无关，并在低q值时转变为标准的q⁻²粘弹性弛豫。利用我们DNA网络的可控特性，我们将这种模式归因于连接性重排引起的局部弹性波动。我们提出了一个简单的珠簧模型，该模型捕捉了这种q⁰行为的基本特征。
