Membrane surface modification

In order to achieve membrane surface modification by chemical reactions, the following approaches have been proposed [3] ... 

This type of surface modification, if adequate functional groups are used, can be useful in incorporating silica particles into polymeric matrices (e.g., into rubber for tires) or in increasing the hydrolytic stability of high-surface-area silica (e.g., that used for membranes). Surface modification of silica is a very important principle and is widely commercialized. 

Another alternative and less common approach for the membrane surface modification is the introduction of an active additive. The basis of this technique is the idea that those additives can move toward the top film surface during membrane formation and alter membrane surface chemistry, while keeping bulk properties unchanged. According to this method, only a very small quantity of the additives is enough to change the surface chemistry of the membranes [36], Blending is a conventional technique used for membrane surface modification, and recently, much attention... 

Wavhal DS and Fisher ER, Membrane surface modification by plasma-induced polymerization of acrylamide for improved surface properties and reduced protein fouling, Langmuir 2003,19, 79-85. 

Membrane Surface Modification and Fonling Resistance of Hydrophilic and Hydrophobic Membranes.368... 

J.E. Kilduff, S. Mattaraj, M. Zhou, G. Belfort, Kinetics of membrane flux decline the role of natural colloids and mitigation via membrane surface modification, J. Nanoparticle Res., 7 (2005) 525-544. 

Polymeric Membranes Surface Modification by Grafting to Method and Fabrication of Multilayered Assemblies... 

FIGURE 3.5 Membrane surface modification via O2 plasma treatment. (Reprinted from Desalination, 189, Tyszler, D., et al., 119-129, Copyright (2006), with permission from Elsevier.)... 

Khayet, M. 2004. Membrane surface modification and characterization by X-ray photoelectron spectroscopy, atomic force microscopy and contact angle measurements. 

Considering the obvious advantages of the membrane surface modification by SMM and the applicability of this principle in manufacturing hydrophobic/hydro-philic membranes for MD, we synthesized four different types of hydrophobic SMMs (nSMMl, nSMM2, nSMM3, and SMM41). These SMMs were then blended into PEI, which is a hydrophilic polymer, to produce novel hydrophobic/hydrophilic composite membranes by the phase inversion method. Finally, these membranes were tested for the desalination of a 0.5 M NaCl solution by DCMD. 

Khayet, M. and Matsuura, T. 2003a. Progress in membrane surface modification by surface modifying macromolecules using polyethersulfone, polyetherimide and polyvinylidene fluoride base polymers Applications in the separation processes ultrafiltration and per-vaporation. Fluid Particle Sep. J. 15(1) 9-21. 

Lopez-Perez, P.M., Marques, A.P., da SUva, R.M.P., Pashkuleva, I. and Reis, R.L. 2007. Effect of chitosan membrane surface modification via plasma induced polymerization on the adhesion of osteoblast-like cells. 

Tu, C.-Y, Wang, Y.-C., Li, C.-L., Lee, K.-R., Huan, J. and Lai, J.-Y. 2005. Expanded poly(tetrafluoroethylene) membrane surface modification using acetylene/nitrogen plasma treatment. 

The formation of ultrathin surface layers (10 nm thick or less), either through bottom-up approaches such as self-assembly or the application of surface coatings through synthetic chemistry on different types of surfaces, is one of the major research areas for membrane surface modification. The main reason for such interest is the number of applications requiring relatively defect-free surfaces with systematically engineered properties. Coatings are predominantly used to enhance the performance of nanofibrous scaffolds. 

Q Development of Membranes for Pervaporation by Membrane Surface Modification and Incorporation of Inorganic Particles... 

Chapter 7 examines the use of plasma treatment for the modification of polymeric membranes. Plasma treatment is carried out at the manbrane surface so that the beneficial properties of the bulk material remain unchanged. Surface properties such as roughness and functionality can be altered to improve the performance of the membrane. All these processes are very quick and the time taken for modification is usually a few seconds up to a few minutes. The method uses chemicals in the gaseous form and produces very small amounts of wastes. Among all techniques of membrane surface modification, plasma treatment seems to be the most versatile and environment-friendly. The authors of Chapter 7 discuss how these benefits impact on membrane modification strategies. 

It is often desirable to alter the surface properties of a membrane, for example to reduce adsorption or to introduce specific groups that can be used for affinity membranes. Surface modification can also be used as a method of changing the separation properties of a material. 

The use of synthetic materials in biomedical applications has increased dramatically dining the past few decades. Surface properties of polymers are of fundamental importance in many branches of industrial applications (e.g., separation of gasses, liquid mixtures, bonding, coating, adhesion, etc.). Performances of membranes also depend on the properties of their surfaces, since membrane performance is strongly influenced by the surface phenomena. Hence, it is very natural that much attention has been paid to the membrane surface modification. Surface contamination which may lead to deterioration in membrane performance is also known to be governed by the membrane surface properties. Detailed methods for modification of synthetic membranes are discussed by Khulbe et al. [63]... 

---