Nanostructure Scaling in Semi‐Dilute Triblock Copolymer Gels
Nanostructure Scaling in Semi‐Dilute Triblock Copolymer Gels
复制标题
半稀三嵌段共聚物凝胶中的纳米结构缩放
DOI：
10.1002/macp.202300093
复制
发表时间：
2023
影响因子：
2.5
通讯作者：
O'Shea, Emma K.
中科院分区：
文献类型：
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作者：
Mineart, Kenneth P.;Vallely, Matthew J.;O'Shea, Emma K.
有相当多的工作描述了基于嵌段聚合度和共聚物浓度的两嵌段共聚物在稀溶液和半稀溶液中胶束尺寸的缩放。然而，半稀ABA三嵌段共聚物凝胶缺乏类似的信息，这种凝胶是由ABA三嵌段共聚物溶解在中间嵌段选择性(B选择性)溶剂中组成的。本研究使用小角X射线散射来提取许多三嵌段共聚物凝胶的胶束尺寸，这些凝胶的共聚物特性(因此嵌段长度)和共聚物浓度不同，以及含有两种不同比例的两种独特的三嵌段共聚物的凝胶。对胶束结构数据的分析随后转化为胶束核半径的通用标度表达式-Ra≈NA0.53Nb−0.14ϕABA0.16，其中NAa和Nb分别是端嵌段和中段的聚合度，ϕABA是三嵌段共聚物在凝胶中的体积分数-以及胶束间距-Laa≈NA0.09NB0.29ϕABA0.35。每个标度表达式都很好地描述了实验数据的完整收集。此外，这些标度表达式部分符合半稀两嵌段共聚物溶液理论的预期。
There is a considerable body of work that describes the scaling of diblock copolymer micelle dimensions in dilute and semi‐dilute solution based upon block degrees of polymerization and copolymer concentration. However, there is a lack of analogous information for semi‐dilute ABA triblock copolymer gels, which consist of ABA triblock copolymer dissolved in midblock‐selective (B‐selective) solvent. The present study uses small angle X‐ray scattering to extract micelle dimensions for numerous triblock copolymer gels that vary in copolymer identity (and hence block lengths) and copolymer concentration, as well as gels that contain various ratios of two unique triblock copolymers. Analysis of micelle structural data subsequently translates to universal scaling expressions for the micelle core radius –rA≈NA0.53NB−0.14ϕABA0.16whereNAandNBare the endblock and midblock degrees of polymerization, respectively, andϕABAis the volume fraction of triblock copolymer in the gel – and for the intermicelle spacing –lAA≈NA0.09NB0.29ϕABA−0.35. Each scaling expression describes the full collection of experimental data very well. Additionally, these scaling expressions are partially in line with expectations from semi‐dilute diblock copolymer solution theory.