Schiavone Maria-Maddalena, Lamparelli David Hermann, Daniel Christophe, Golla Manuchar, Zhao Yue, Iwase Hiroki, Arima-Osonoi Hiroshi, Takata Shin-Ichi, Szentmiklosi Laszlo, Maroti Boglarka, Allgaier Jürgen, Radulescu Aurel
Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, Garching, 85747, Germany.
Dipartimento di Chimica e Biologia 'Adolfo Zambelli', Università di Salerno, Fisciano, I-84084, Italy.
J Appl Crystallogr. 2023 Jul 25;56(Pt 4):947-960. doi: 10.1107/S1600576723005496. eCollection 2023 Aug 1.
Semi-crystalline polymers exhibit microphase separation into crystalline and amorphous domains characterized by multiple structural levels with sizes ranging from ångströms to hundreds of nanometres. The combination of small-angle (SANS) and wide-angle (WANS) neutron scattering on the same beamline enables reliable characterization of such materials under application-relevant conditions, with the unique advantage of contrast variation by controlled labelling, allowing the structure of such multi-component systems to be resolved in detail. This paper reports a structural analysis performed on deuterated polymer membranes based on syndiotactic polystyrene (sPS) using an extended -range SANS and WANS combination, always with the same neutron scattering instrument, either a pinhole SANS diffractometer installed at a research reactor or a 'small- and wide-angle' time-of-flight diffractometer installed at a neutron spallation source. sPS is a semi-crystalline material that becomes hydrophilic and proton conducting when suitable functionalization is achieved by thin film sulfonation, and can form various co-crystalline complexes (clathrates) with small organic molecules stored in the crystalline phase as guests in the vacancies between the polymer helices. Therefore, this material is interesting not only for its conducting properties but also for its versatility as a model system to evaluate the usefulness of extended -range neutron scattering in such studies. Variation of neutron contrast was achieved in the amorphous hydrophilic phase by using HO or DO to hydrate the membranes and in the crystalline phase by loading the clathrates with deuterated or protonated guest molecules. The experimental approach, the advantages and limitations of the two types of instrumentation used in such analyses, and the main results obtained with respect to the structural characterization of sulfonated sPS membranes under different hydration and temperature conditions are reported, and the potential of this method for similar structural studies on other semi-crystalline polymeric materials is discussed.
半结晶聚合物呈现出微相分离，形成结晶域和非晶域，其特征在于具有多个结构层次，尺寸范围从埃到数百纳米。在同一束线上进行小角（SANS）和广角（WANS）中子散射相结合，能够在与应用相关的条件下可靠地表征此类材料，具有通过可控标记实现对比度变化的独特优势，从而能够详细解析此类多组分系统的结构。本文报道了基于间规聚苯乙烯（sPS）的氘代聚合物膜的结构分析，使用了扩展范围的SANS和WANS组合，且始终使用同一台中子散射仪器，即安装在研究堆上的针孔SANS衍射仪或安装在中子散裂源上的“小角和广角”飞行时间衍射仪。sPS是一种半结晶材料，当通过薄膜磺化实现适当的功能化时，它会变得亲水并具有质子传导性，并且可以与作为客体存储在聚合物螺旋之间空位的结晶相中的小有机分子形成各种共晶络合物（包合物）。因此，这种材料不仅因其导电性能而有趣，还因其作为模型系统的多功能性而有趣，可用于评估扩展范围中子散射在此类研究中的实用性。通过使用H₂O或D₂O使膜水合，在非晶亲水相中实现中子对比度的变化；通过用氘代或质子化的客体分子加载包合物，在结晶相中实现中子对比度的变化。报道了实验方法、此类分析中使用的两种仪器的优缺点，以及在不同水合和温度条件下磺化sPS膜结构表征所获得的主要结果，并讨论了该方法对其他半结晶聚合物材料进行类似结构研究的潜力。
