Gutierrez-Fernandez Edgar, Ezquerra Tiberio A, García-Gutiérrez Mari-Cruz
Instituto de Estructura de la Materia (IEM-CSIC), Serrano 121, 28006 Madrid, Spain.
Polymers (Basel). 2021 Dec 30;14(1):141. doi: 10.3390/polym14010141.
We reported on the interaction between poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and high-boiling-point additives in PEDOT:PSS aqueous dispersions and in the final polymer films with the aim of stablishing correlations between the structure of both inks and solid thin films. By Small-Angle X-ray Scattering (SAXS) using synchrotron radiation, it was found that the structural changes of dispersions of PEDOT:PSS with high-boiling-point additives can be explained as a two-step mechanism depending on the additive concentration. A compaction of PEDOT:PSS grains was observed at low concentrations while a swelling of the grains together with a phase segregation between PEDOT and PSS segments was evidenced at larger concentrations. Thin films' morphology and structure were investigated by atomic force microscopy (AFM) and synchrotron Grazing Incidence Wide-Angle X-ray Scattering (GIWAXS) respectively. Our two-step model provides an explanation for the small and sharp domains of PEDOT:PSS thin films observed for low-additive concentrations (first step) and larger domains and roughness found for higher-additive concentrations (second step). A reduction of the ratio of PSS in PEDOT:PSS thin films upon the presence of additives was also observed. This can be related to a thinning of the PSS shells of PEDOT:PSS grains in the dispersion. The results discussed in this work provide the basis for a controlled tuning of PEDOT:PSS thin films structure and the subsequent electrical properties.
我们报道了聚（3,4 - 亚乙基二氧噻吩）：聚苯乙烯磺酸盐（PEDOT:PSS）与PEDOT:PSS水分散体以及最终聚合物薄膜中的高沸点添加剂之间的相互作用，目的是建立两种油墨和固体薄膜结构之间的相关性。通过使用同步辐射的小角X射线散射（SAXS）发现，PEDOT:PSS与高沸点添加剂分散体的结构变化可以用一种取决于添加剂浓度的两步机制来解释。在低浓度下观察到PEDOT:PSS颗粒的压实，而在较高浓度下则证明颗粒膨胀以及PEDOT和PSS链段之间的相分离。分别通过原子力显微镜（AFM）和同步辐射掠入射广角X射线散射（GIWAXS）研究了薄膜的形态和结构。我们的两步模型解释了在低添加剂浓度下观察到的PEDOT:PSS薄膜的小而尖锐的区域（第一步）以及在高添加剂浓度下发现的较大区域和粗糙度（第二步）。还观察到在添加剂存在下PEDOT:PSS薄膜中PSS比例的降低。这可能与分散体中PEDOT:PSS颗粒的PSS壳变薄有关。这项工作中讨论的结果为可控调节PEDOT:PSS薄膜结构及其后续电学性能提供了基础。
