本研究用相转化法对聚偏氟乙烯（PVDF）超滤膜进行了乙烯-乙烯醇共聚物（EVOH）共混改性，系统考察PVDF/EVOH共混比和凝胶浴温度对共混膜性能的影响.并使用原子力显微镜（AFM）胶体探针定量测定了共混改性前后，亲/疏水性污染物与膜之间作用力的变化特点，结合宏观过滤实验解析添加EVOH对PVDF抗污染性能的影响.结果表明：PVDF/EVOH相容性最佳的共混比为9/1.与纯PVDF膜相比，PVDF/EVOH共混膜的亲水性明显提高.共混膜的亲水性及拉伸强度随着凝胶浴温度的增大而增大，但是纯水通量随着凝胶浴温度的增大而减小.主要是因为高凝胶浴条件下膜表面有致密的皮层形成。膜-污染物间作用力及污染试验表明，添加EVOH后有效降低了膜-污染物间的相互作用力及相应的膜污染速率，表明了EVOH的引入能有效改善了膜的抗污染性.

Polyvinylidene fluoride (PVDF)/ethylene vinyl alcohol copolymer (EVOH) blend membranes were prepared by phase inversion. The influence of PVDF/EVOH blend ratio and coagulation bath temperature on the properties of the blend membrane was investigated. Typical foulant probes were used to measure the change of foulant-membrane interaction force before and after the blend modification of PVDF membranes and analyze the antifouling characteristics of the modified membrane. Results show that the optimum blending weight ratio of PVDF/EVOH compatibility was 9/1. The PVDF/EVOH membrane presented more hydrophilic than the pure PVDF membrane. The hydrophilicity and mechanical strength of blend membrane obtained increased with an increase on the coagulation bath temperature during the preparation, whereas its pure water flux decreased. The main reason is that PVDF/EVOH blend membrane with a dense layer in the surface formed. It is also found that the interaction forces between PVDF/EVOH and foulant were much weaker than that those between the pure PVDF membrane and foulant. It suggests that the antifouling ability of PVDF membrane was effectively improved by blending EVOH.

[1] Gu M, Zhang J, Wang X L. Formation of polyvinylidene fluoride (PVDF) membranes via thermally induced phase separation[J]. Desalination, 2006, 192(1/3): 160-16.
[2] Li F, Hashim N A, Liu Y, et al. Progress in the production and modification of PVDF membranes[J]. Journal of Membrane Science, 2011, 375(1-2): 1-27.
[3] Venault A, Liu Y H, Wu J R, et al. Low-biofouling membranes prepared by liquid-induced phase separation of the PVDF/polystyrene-b-poly (ethylene glycol) methacrylate blend[J]. Journal of Membrane Science, 2014, 450: 340-350.
[4] Sigal G B, Mrksich M, Whitesides G M. Effect of surface wettability on the adsorption of proteins and detergents[J]. Journal of the American Chemical Society, 1998, 120(14): 3464-3473.
[5] Fang F, Szleifer I. Effect of molecular structure on the adsorption of protein on surfaces with grafted polymers[J]. Langmuir, 2002, 18: 5497-5510.
[6] Sadana A. Protein adsorption and inactivation on surfaces influence of heterogeneities[J]. Chemical reviews, 1992, 92: 1799.
[7] Wei Y, Chu H Q, Dong B Z, et al. Effect of TiO2 nanowire addition on PVDF ultra?ltration membrane performance[J]. Desalition, 2011, 272: 90-97.
[8] Zhang C H, Yang F L, Wang W J, et al. Preparation and characterization of hydrophilic modification of polypropylene non-woven fabric by dip-coating PVA (polyvinyl alcohol)[J]. Separation and Purification Technology, 2008, 61: 276-286.
[9] Philip S Y, James E K, Georges B. Fouling-resistant properties of a surface-modi?ed polyether sulfone ultra?ltration membrane grafted with polyethylene glycol-amide binary monomers[J]. Journal of membrane science, 2011, 377: 159-166.
[10] 蔡报祥,于水利,卢艳. PVDF纳米A1203共混超滤膜的制备及其性能[J]. 北京交通大学学报, 2007, 39(6): 879-882.
[11] 董声雄,龚琦,黄加乐,等.聚偏氟乙烯/聚醋酸乙烯酯共混小截留分子量超滤膜[J]. 化工学报, 2002, 53(11):1212-1214.
[12] Costas K S, Nikos K K. Compatibilization of polyethylene-co-vinyl alcohol (EVOH) and EVOH/HDPE blends with ionomers[J]. Structure and properties Polymer, 1998, 39(16): 3863-3870.
[13] Wang L, Miao R, Wang X, et al. Fouling behavior of typical organic foulants in polyvinylidene fluoride ultrafiltration membranes: characterization from microforces[J]. Environmental Science & Technology, 2013, 47(8): 3708-3714.
[14] Sang Y L, Wui S A, Menachem E. Fouling of reverse osmosis membranes by hydrophilic organic matter: implications for water reuse[J]. Desalination, 2006, 187: 313-321.
[15] Hiroshi T, Yoshimasa W. Organic Fouling and Chemical Cleaning of Nanofiltration Membranes: Measurements and Mechanisms[J]. Environmental Science & Technology, 2004, 38: 4683-4693.
[16] Hiroshil Y, Katsuki K, Takahayu O. Affinity of Functional Groups for Membrane Surfaces: Implications for Physically Irreversible Fouling[J]. Environmental Science & Technology, 2008, 42: 5310-5315.
[17]王冈全,王秀芬.聚合物改性[M]. 北京: 中国轻工业出版社, 2000: 43—47; 273—274．
[18] Juliana Aristéia de Lima, Maria Isabel Felisberti. Porous polymer structures obtained via the TIPS process from EVOH/PMMA/DMF solutions[J]. Journal of Membrane Science, 2009, 344: 237-243.
[19] Wavhal D S, FisherI E R. Hydrophilic modification of polyethersulfone membranes by low temperature plasma-induced graft polymerization[J]. Journal of membrane science, 2002, 209: 255-269.
[20] Wavhal D S, FisherI E R. Membrane surface modification by plasma-induced polymerization of acrylamide for improved surface properties and reduced protein foulin, Langmuir, 2003, 9: 79– 85.
[21] 孙晓晓,桓秀颖,王世哲,等.PP/UHMWPE及含有不同添加剂共混物的研究[J]. 合成技术及应用, 2011, 26(3).
[22] Bowen W R, Hilal N, Lovitt R W, Wright C J. A new technique for membrane characterisation: Direct measurement of the force of adhesion of a single particle using an atomic force microscope[J]. Journal of membrane science, 1998, 139: 269-274.
[23] Butt H J, Cappella B, Kappl M. Force measurements with the atomic force microscope: Technique, interpretation and applications[J]. Surf. Sci. Rep., 2005, 59: 1–152.