Department of Mechanical, Industrial, and Manufacturing Engineering , University of Toledo , 2801 W. Bancroft Street , Toledo , Ohio 43606 , United States.
Department of Chemical Engineering , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States.
ACS Appl Mater Interfaces. 2019 Feb 20;11(7):7330-7337. doi: 10.1021/acsami.8b18523. Epub 2019 Feb 8.
Blockage of pipelines due to accretion of salt particles is detrimental in desalination and water-harvesting industries as they compromise productivity, while increasing maintenance costs. We present a micro-/nanoscale approach to study fundamentals of scale formation, deposition, and adhesion to engineered surfaces with a wide range of surface energies fabricated using the initiated chemical vapor deposition method. Silicon wafers and steel substrates are coated with poly(1 H,1 H,2 H,2 H-perfluorodecylacrylate) or pPFDA, poly(tetravinyl-tetramethylcyclotetrasilohexane) or pV4D4, poly(divinylbenzene) or pDVB, poly(1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasilohexane) or pV3D3, and cross-linked copolymers of poly(2-hydroxyethylmethacrylate) and poly(ethylene glycol) diacrylate or p(PHEMA- co-EGDA). Particles of salt (CaSO·2HO) are formed and shaped with a focused ion beam and adhered to a tipless cantilever beam using a micromanipulator setup to study their adhesion strength with a molecular force probe (MFP). Adhesion forces were measured on the substrates in wet and dry conditions to evaluate the effects of interfacial fluid layers and capillary bridges on net adhesion strength. The adhesion between salt particles and the pPFDA coatings decreased by 5.1 ± 1.15 nN in wet states, indicating the influence of capillary bridging between the particle and the liquid layer. In addition, scale nucleation and growth on various surfaces is examined using a quartz crystal microbalance (QCM), where supersaturated solution of CaSO·2HO is passed over bare and polymer-coated quartz substrates while mass gain is measured in real time. The salt accretion decreased by 2 folds on pPFDA-coated substrates when compared to that on p(HEMA- co-EGDA) coatings. Both MFP and QCM studies are essential in studying the impact of surface energy and roughness on the extent of scale formation and adhesion strength. This study can pave way for the design of scale-resistant surfaces with potential applications in water treatment, energy harvesting, and purification industries.
由于盐颗粒的堆积导致管道堵塞，在海水淡化和集水行业中是有害的，因为这会降低生产力，同时增加维护成本。我们提出了一种微/纳米级方法来研究使用引发化学气相沉积法制造的具有广泛表面能的工程表面上的结垢形成、沉积和附着的基本原理。硅片和钢基底用聚(1 H,1 H,2 H,2 H-全氟癸基丙烯酸酯)或 pPFDA、聚(四乙烯基四甲基环四硅氧烷)或 pV4D4、聚(二乙烯基苯)或 pDVB、聚(1,3,5,7-四乙烯基-1,3,5,7-四甲基环四硅氧烷)或 pV3D3 以及聚(2-羟乙基甲基丙烯酸酯)和聚(乙二醇)二丙烯酸酯的交联共聚物 p(PHEMA-co-EGDA)进行涂覆。使用聚焦离子束形成和塑造盐（CaSO·2HO）颗粒，并使用微操作器设置将其粘附到无尖端的悬臂梁上，使用分子力探针 (MFP) 研究其与基底的附着强度。在湿态和干态下测量基底上的附着 力，以评估界面流体层和毛细桥对净附着强度的影响。在湿态下，盐颗粒和 pPFDA 涂层之间的附着强度降低了 5.1±1.15 nN，表明颗粒和液体层之间存在毛细桥的影响。此外，使用石英晶体微天平 (QCM) 检查各种表面上的结垢成核和生长，其中将过饱和的 CaSO·2HO 溶液通过裸基底和聚合物涂覆的石英基底，同时实时测量质量增加。与 p(HEMA-co-EGDA)涂层相比，pPFDA 涂覆基底上的盐积存量减少了 2 倍。MFP 和 QCM 研究对于研究表面能和粗糙度对结垢程度和附着强度的影响至关重要。这项研究为设计具有抗结垢表面的潜力铺平了道路，这些表面具有在水处理、能源收集和净化工业中的潜在应用。
