Jouault Nicolas, Jestin Jacques
Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire PHENIX, Case 51, 4 place Jussieu, F-75005 Paris, France.
Laboratoire Léon Brillouin (LLB), CEA Saclay, 91191 Gif-Sur-Yvette, France.
ACS Macro Lett. 2016 Oct 18;5(10):1095-1099. doi: 10.1021/acsmacrolett.6b00500. Epub 2016 Sep 15.
In this Letter we applied for the first time a small-angle neutron scattering (SANS) extrapolation method to study the influence of nanoparticles (NPs) on polymer chain conformation in polymer nanocomposites (PNCs). This new approach is based on a perfect NP matching thanks to a statistical hydrogenated (H)/ deuterated (D) polymer matrix in which a certain amount of labeled chain (H) is added. The extrapolation to zero H content gives the intrachain structure factor, (), and the interchain correlations, (), the latter not being accessible under the zero average contrast (ZAC) condition preferentially used in the previous studies. We validate the method on well-known silica/polystyrene (PS) PNCs and compare the results with our previous ZAC measurements. The analysis of both () and () shows (i) no significant modifications of the radius of gyration of the chain and of the interchain interaction induced by the presence of NPs and more interestingly (ii) the existence of chain domains with lower densities included inside NP clusters as the result of excluded volume effects that create an extra scattering at low . The extrapolation method unambiguously shows that the unexpected behavior observed at low comes from the chains and not from the unmatched NPs.
在本信函中，我们首次应用小角中子散射（SANS）外推法来研究纳米颗粒（NPs）对聚合物纳米复合材料（PNCs）中聚合物链构象的影响。这种新方法基于一种完美的NP匹配，这得益于一种统计氢化（H）/氘化（D）聚合物基体，其中添加了一定量的标记链（H）。外推至零H含量可得到链内结构因子S_c(q)和链间相关性S_i(q)，而后者在先前研究中优先使用的零平均对比度（ZAC）条件下是无法获得的。我们在著名的二氧化硅/聚苯乙烯（PS）PNCs上验证了该方法，并将结果与我们之前的ZAC测量结果进行了比较。对S_c(q)和S_i(q)的分析表明：（i）NPs的存在对链的回转半径和链间相互作用没有显著影响，更有趣的是（ii）由于排除体积效应，在NP簇内部存在密度较低的链域，这在低q值处产生了额外的散射。外推法明确表明，在低q值处观察到的意外行为来自链，而非不匹配的NPs。
