Structure Dominates Localization of Tracers within Aging Nanoparticle Glasses
Structure Dominates Localization of Tracers within Aging Nanoparticle Glasses
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结构主导老化纳米粒子玻璃内示踪剂的定位
DOI：
10.1021/acs.jpclett.9b00309
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Conrad, Jacinta C.
中科院分区：
文献类型：
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作者：
Poling-Skutvik, Ryan;Roberts, Ryan C.;Slim, Ali H.;Narayanan, Suresh;Krishnamoorti, Ramanan;Palmer, Jeremy C.;Conrad, Jacinta C.
我们调查的运输和本地化的示踪剂探针在玻璃基质中的相对大小的函数，使用动态X射线散射实验和分子动力学模拟。示踪粒子的静态弛豫随等待时间的增加而变化。相应的弛豫时间在小周呈指数增长，然后在长周过渡到幂律行为。随着示踪剂尺寸的减小，老化行为减弱，并且颗粒在基体内变得不那么局域化，直到它们在临界尺寸比δ0 <$0.38处离域。本地化不随样品年龄变化，即使松弛慢约一个数量级，这表明矩阵结构控制示踪剂本地化。
We investigate the transport and localization of tracer probes in a glassy matrix as a function of relative size using dynamic X-ray scattering experiments and molecular dynamics simulations. The quiescent relaxations of tracer particles evolve with increasing waiting time,tw. The corresponding relaxation times increase exponentially at smalltwand then transition to a power-law behavior at longertw. As tracer size decreases, the aging behavior weakens and the particles become less localized within the matrix until they delocalize at a critical size ratio δ0≈ 0.38. Localization does not vary with sample age even as the relaxations slow by approximately an order of magnitude, suggesting that matrix structure controls tracer localization.