Luo Yan, Wang Xiaoteng, Zhang Ren, Singh Maninderjeet, Ammar Ali, Cousins Diana, Hassan Mohammad K, Ponnamma Deepalekshmi, Adham Samer, Al-Maadeed Mariam Al Ali, Karim Alamgir
Department of Polymer Engineering, University of Akron, Akron, OH 44325, USA.
Soft Matter. 2020 Nov 4;16(42):9648-9654. doi: 10.1039/d0sm00526f.
The separation of oil from water and filtration of aqueous solutions and dispersions are critical issues in the processing of waste and contaminated water treatment. Membrane-based technology has been proven as an effective method for the separation of oil from water. In this research, novel vertical nanopores membrane, via oriented cylindrical block copolymer (BCP) films, suitable for oil/water filtration has been designed, fabricated and tested. We used a ∼100 nm thick model poly(styrene-block-methymethacrylate) (PS-b-PMMA) BCP as the active top nanofiltration layer, processed using a roll-to-roll (R2R) method of cold zone annealing (CZA) to obtain vertical orientation, followed by ultraviolet (UV) irradiation selective etch of PMMA cylinders to form vertically oriented nanopores as a novel feature compared to meandering nanopores in other reported BCP systems. The cylindrical nanochannels are hydrophilic, and have a uniform pore size (∼23 nm), a narrow pore size distribution and a high nanopore density (∼420 per sq. micron). The bottom supporting layer is a conventional microporous polyethersulfone (PES) membrane. The created asymmetric membrane is demonstrated to be effective for oil/water extraction with a modestly high throughput rate comparable to other RO/NF membranes. The molecular weight dependent filtration of a water soluble polymer, PEO, demonstrates the broader applications of such membranes.
油水分离以及水溶液和分散体的过滤是废水和污水处理过程中的关键问题。基于膜的技术已被证明是一种有效的油水分离方法。在本研究中，通过取向圆柱状嵌段共聚物（BCP）薄膜设计、制备并测试了适用于油/水过滤的新型垂直纳米孔膜。我们使用约100 nm厚的聚（苯乙烯-嵌段-甲基丙烯酸甲酯）（PS-b-PMMA）BCP模型作为活性顶部纳滤层，采用卷对卷（R2R）冷区退火（CZA）方法进行处理以获得垂直取向，随后对PMMA圆柱进行紫外（UV）辐照选择性蚀刻，从而形成垂直取向的纳米孔，这是与其他报道的BCP系统中蜿蜒状纳米孔相比的一个新特征。圆柱形纳米通道具有亲水性，孔径均匀（约23 nm），孔径分布窄且纳米孔密度高（约每平方微米420个）。底部支撑层是传统的微孔聚醚砜（PES）膜。所制备的不对称膜被证明对油/水萃取有效，通量率适中且较高，与其他反渗透/纳滤膜相当。对水溶性聚合物聚环氧乙烷（PEO）的分子量依赖性过滤证明了此类膜具有更广泛的应用。
