Small-Angle Neutron Scattering Study on Defect-Controlled Polymer Networks
Small-Angle Neutron Scattering Study on Defect-Controlled Polymer Networks
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DOI：
10.1021/ma402590n
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发表时间：
2014-02
期刊：
影响因子：
5.5
通讯作者：
Kengo Nishi;Hanako Asai;K. Fujii;Young-Soo Han;Tae-Hwan Kim;T. Sakai;M. Shibayama
中科院分区：
文献类型：
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作者：
Kengo Nishi;Hanako Asai;K. Fujii;Young-Soo Han;Tae-Hwan Kim;T. Sakai;M. Shibayama
小角中子散射（SANS）证实了四聚乙二醇凝胶具有明显低不均匀性的接近“理想”网络。在本研究中，我们系统地将两种缺陷引入到四聚乙二醇凝胶中，并研究了缺陷对结构的影响。首先，我们通过简单降低预聚物浓度制备了富含缺陷的网络，并通过时间分辨SANS观察了凝胶化过程中网络结构的演变。在这种情况下，在φ φ *区域，散射强度和相关长度都随着反应时间的增加而增加。其中，φ和φ *分别为观察时聚合物体积分数和链重叠浓度时聚合物体积分数。其次，我们通过调整反应概率p来制备“p调谐”的四聚乙二醇凝胶，并将其浸泡在水中以暴露其不均匀性。结果表明，制备凝胶的SANS谱无明显变化，而肿胀凝胶系统的SANS谱无明显变化。
Tetra-PEG gels are classified to near-“ideal” networks with significantly low inhomogeneities, which were confirmed by small-angle neutron scattering (SANS). In this study, we systematically introduced two types of defects into Tetra-PEG gels and investigated effects of defects on structure. First, we prepared defect-rich networks by simply reducing prepolymer concentration, and observed the evolution of network structure by time-resolved SANS during gelation process. In this case, both the scattering intensity and the correlation length increased with reaction time in the ϕ ϕ* region. Here, ϕ and ϕ* are the polymer volume fractions at observation and that at chain-overlap concentration, respectively. Second, we prepared “p-tuned” Tetra-PEG gels by tuning the reaction probability, p, and soaked them in water to expose the inhomogeneities. It was revealed that SANS profiles of as-prepared gels did not change noticeably, while those of swollen gels systema...