Eddine Malak Alaa, Carvalho Alain, Schmutz Marc, Salez Thomas, de Chateauneuf-Randon Sixtine, Bresson Bruno, Belbekhouche Sabrina, Monteux Cécile
Laboratoire Sciences et Ingénierie de la Matière Molle, ESPCI Paris, 10 rue Vauquelin, 75231 Cedex 05 Paris, France.
Université Paris Est Creteil, CNRS, Institut Chimie et Matériaux Paris Est, UMR 7182, 2 Rue Henri Dunant, 94320 Thiais, France.
Langmuir. 2023 Oct 24;39(42):15085-15094. doi: 10.1021/acs.langmuir.3c02153. Epub 2023 Oct 12.
Hydrogels are promising systems for separation applications due to their structural characteristics (i.e., hydrophilicity and porosity). In our study, we investigate the permeation of suspensions of rigid latex particles of different sizes through free-standing hydrogel membranes prepared by photopolymerization of a mixture of poly(ethylene glycol) diacrylate (PEGDA) and large poly(ethylene glycol) (PEG) chains of 300,000 g·mol in the presence of a photoinitiator. Atomic force microscopy and cryoscanning electron microscopy (cryoSEM) were employed to characterize the structures of the hydrogel membranes. We find that the 20 nm particle permeation depends on both the PEGDA/PEG composition and the pressure applied during filtration. In contrast, we do not measure a significant permeation of the 100 nm and 1 μm particles, despite the presence of large cavities of 1 μm evidenced by the cryoSEM images. We suggest that the PEG chains induce local nanoscale defects in the cross-linking of PEGDA-rich walls separating the micrometer-sized cavities, which control the permeation of particles and water. Moreover, we discuss the decline of the permeation flux observed in the presence of latex particles compared to that of pure water. We suggest that a thin layer of particles forms on the surface of the hydrogels.
由于水凝胶的结构特性（即亲水性和孔隙率），它们是用于分离应用的有前景的体系。在我们的研究中，我们研究了不同尺寸的刚性乳胶颗粒悬浮液通过由聚（乙二醇）二丙烯酸酯（PEGDA）和300,000 g·mol的大聚（乙二醇）（PEG）链的混合物在光引发剂存在下光聚合制备的自支撑水凝胶膜的渗透情况。采用原子力显微镜和低温扫描电子显微镜（cryoSEM）来表征水凝胶膜的结构。我们发现20 nm颗粒的渗透取决于PEGDA/PEG组成以及过滤过程中施加的压力。相比之下，尽管cryoSEM图像显示存在1μm的大孔洞，但我们并未检测到100 nm和1μm颗粒的显著渗透。我们认为PEG链在分隔微米级孔洞的富含PEGDA的壁的交联中诱导局部纳米级缺陷，这些缺陷控制着颗粒和水的渗透。此外，我们讨论了与纯水相比，在存在乳胶颗粒时观察到的渗透通量的下降。我们认为在水凝胶表面形成了一层薄的颗粒层。
