Glass transition and relaxation processes of nanocomposite polymer electrolytes.
Glass transition and relaxation processes of nanocomposite polymer electrolytes.
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DOI：
10.1021/jp3036499
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发表时间：
2012-06
期刊：
影响因子：
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通讯作者：
B. K. Money;K. Hariharan;J. Swenson
中科院分区：
文献类型：
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作者：
B. K. Money;K. Hariharan;J. Swenson
研究了δ-Al（2）O（3）纳米填料对聚合物电解质（PEO）（4）：LiClO（4）的直流电导率、玻璃化转变和介电弛豫的影响。结果表明，体系中存在α、β和γ三个介电弛豫过程，但结构上的α弛豫过程隐藏在强电导贡献中，不能直接观测到.然而，通过比较增加的直流电导率（添加4 wt % δ-Al（2）O（3）约2个数量级）与量热玻璃化转变温度的降低，我们能够得出结论，直流电导率直接与隐藏的α弛豫耦合，甚至在纳米填料存在下（至少在浓度高达4wt%的δ-Al（2）O（3）纳米填料的情况下）。这种填料引起链段聚合物动力学的加速，即，α-弛豫可以通过聚合物-填料相互作用的非吸引性质来解释，这增强了填料表面附近的聚合物链段的“自由体积”和流动性。
This study focus on the effect of δ-Al(2)O(3) nanofillers on the dc-conductivity, glass transition, and dielectric relaxations in the polymer electrolyte (PEO)(4):LiClO(4). The results show that there are three dielectric relaxation processes, α, β, and γ, in the systems, although the structural α-relaxation is hidden in the strong conductivity contribution and could therefore not be directly observed. However, by comparing an enhanced dc-conductivity, by approximately 2 orders of magnitude with 4 wt % δ-Al(2)O(3) added, with a decrease in calorimetric glass transition temperature, we are able to conclude that the dc-conductivity is directly coupled to the hidden α-relaxation, even in the presence of nanofillers (at least in the case of δ-Al(2)O(3) nanofillers at concentrations up to 4 wt %). This filler induced speeding up of the segmental polymer dynamics, i.e., the α-relaxation, can be explained by the nonattractive nature of the polymer-filler interactions, which enhance the "free volume" and mobility of polymer segments in the vicinity of filler surfaces.