Thermal Control of Confined Crystallization within P3EHT Block Copolymer Microdomains
Thermal Control of Confined Crystallization within P3EHT Block Copolymer Microdomains
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P3EHT 嵌段共聚物微域内限制结晶的热控制
DOI：
10.1021/acs.macromol.7b01616
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发表时间：
2017
期刊：
影响因子：
5.5
通讯作者：
Segalman, Rachel A.
中科院分区：
文献类型：
--
作者：
Davidson, Emily C.;Segalman, Rachel A.
共轭聚合物中微晶的局部纳米尺度组织通常对决定体系的电荷传输性质至关重要。嵌段共聚物的几何构型提供了可控的纳米结构，并在界面上形成了链的连接，是研究共轭聚合物微晶局部组织的理想平台。模型共轭聚合物聚(3-(2‘-乙基)己基噻吩基)(P3EHT)相对于被广泛研究的聚(3-己基噻吩基)(P3HT)具有较低的熔融温度，这使得它能够牢固地形成微相分离的微区，从而限制了后续的P3EHT微晶。重要的是，约束条件下的P3EHT结晶通过界面系留、力学性能和链拉伸与橡胶第二嵌段偶联。在这里，研究了热加工对两嵌段共聚物结构的影响，以阐明控制最终耦合的两嵌段共聚物和结晶结构的关键驱动力。令人惊讶的是，共轭结构域结晶的温度显著影响着两嵌段共聚物结构域的大小。随着结晶温度的升高，微区延伸量逐渐减少。这种与温度有关的磁区结构似乎与结晶过程有关；这些过程是从熔化过程中片层结构的精确变化中推断出来的。通过仔细跟踪熔化过程中磁区结构的变化，这项工作确定了三种不同的制度。我们提出了一个共轭块熔化过程的结构模型，它包括(I)排除链松弛，然后(Ii)熔融-再结晶过程中的链交错，最后(Iii)与初始结晶条件无关的完全熔化。这些结果表明，与温度相关的链扩散和成核相关的P3EHT结晶过程是导致意外的温度相关结晶行为的主要原因。他们还强调，不那么完美的共轭聚合物晶体实际上可能与糟糕的交错结构有关。此外，这项工作证明了利用具有橡胶第二嵌段的两嵌段共聚物结构来精确跟踪微晶结构的变化。
The local, nanoscale organization of crystallites in conjugated polymers is often critical to determining the charge transport properties of the system. Block copolymer geometries, which offer controlled nanostructures with tethering of chains at interfaces, are an ideal platform to study the local organization of conjugated polymer crystallites. The model conjugated polymer poly(3-(2′-ethyl)hexylthiophene) (P3EHT) features a depressed melting temperature relative to the widely studied poly(3-hexylthiophene) (P3HT), which allows it to robustly form microphase-separated domains that confine the subsequent P3EHT crystallites. Importantly, P3EHT crystallization in confinement is coupled to a rubbery second block via interfacial tethering, mechanical properties, and chain stretching. Here, the impact of thermal processing on the diblock copolymer structure is examined to elucidate the key driving forces controlling the final coupled diblock copolymer and crystalline structures. Surprisingly, the diblock copolymer domain size is significantly impacted by the temperature at which the conjugated domain is crystallized. Decreasing amounts of domain extension are observed with increasing crystallization temperatures. This temperature-dependent domain structure appears to be correlated with the crystallization processes; these processes are inferred from precise changes in the lamellar structure across melting. By carefully tracking the changes in domain structure across melting, this work identifies three distinct regimes. We suggest a structural model of the conjugated block melting processes consisting of (I) excluded-chain relaxation, followed by (II) chain interdigitation during melt-recrystallization, and finally (III) complete melting that is independent of the initial crystallization conditions. These results suggest that P3EHT crystallization processes associated with temperature-dependent chain diffusion and nucleation are primarily responsible for the unexpected temperature-dependent crystallization behavior. They also emphasize that less perfect conjugated polymer crystals may actually be associated with a poorly interdigitated structure. Furthermore, this work demonstrates the utility of leveraging a diblock copolymer structure with a rubbery second block in order to precisely track changes in the crystallite structure.
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DOI：
--
发表时间：
1991
期刊：
影响因子：
--
作者：
K. Douzinas;R. Cohen;A. Halasa
通讯作者：
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影响因子：
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作者：
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通讯作者：
DeLongchamp, Dean M.
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影响因子：
5.5
作者：
W. Mulhearn;R. Register
通讯作者：
R. Register
圆柱形 P3EHT 嵌段共聚物微域内的限域结晶
影响因子：
5.5
作者：
Davidson, Emily C.;Segalman, Rachel A.
通讯作者：
Segalman, Rachel A.
形成聚(3-(2-乙基)己基噻吩)(P3EHT)嵌段共聚物的片层中的限制结晶
DOI：
10.1002/polb.23904
发表时间：
2016
期刊：
Journal of Polymer Science Part B
影响因子：
--
作者：
E. Davidson;B. Beckingham;Victor Ho;R. Segalman
通讯作者：
R. Segalman