Surface modification techniques polymerization

Similar to static contact angles from the sessile droplet method, Wilhelmy dynamic contact angles are an excellent indication of the change in surface characteristics due to surface modification techniques such as plasma polymerization coating. The cosine of dynamic advancing contact angles from the first immersion, cos 0D,a,i of untreated, TMS-treated, and (TMS-I-02)-treated conventional... 

Attempts have been made to design packings with an expanded pH compatibility compared to silica, but with a hardness comparable to silica. Other inorganic carriers such as alumina, titania, and zirconia have been explored. Indeed, their hardness matches that of silica, and being impervious to small molecules, they also exhibit the same advantageous mass-transfer properties as silica. However, no simple surface modification techniques are available as yet that match the silanization chemistry used for silica. Therefore, polymeric coatings have been used, which then in turn exhibit inferior mass-transfer behavior. 

With the recent advances in the development of novel polymeric biomaterials along with surface modification techniques, significant research effort has been devoted toward fabrication of fully polymeric valves as an attractive alternative to mechanical and bioprosthetic valves [128]. Development of these types of valves is specifically appealing, since polymeric materials offer significant flexibility in terms of material properties and manufacturing process to achieve reduced thrombogenicity and improved durability and biocompatibility [127,128]. However, fully poly-... 

Bioactive molecules can be immobilized on polymeric surfaces by covalent chemical attachment or physical adsorption [251]. Solid polymer surfaces with reactive functional groups (OH, NH, COOH, SH, and CHCH ) present an opportunity for covEdent conjugation with biomolecules either directly or via a spacer linker [251]. Relatively inert polymers can also be treated with surface modification techniques to introduce reactive functional groups and allow chemical functionalization with desired biochemical moieties [251], Alternatively, biomolecules can also be physically immobilized on polymeric surfaces via van der Waal forces, affinity binding, or electrostatic interaction [251]. Notably, these biomolecules must be presented on the material surfaces with stabilized conformations and correct orientations to preserve their bioactivity [252-255]. 

FIGURE 23.2 Surface modification techniques of electrospun nanofibers, (a) Plasma treatment or wet chemical method, (b) Surface graft polymerization. (c) Coelectrospinning. Reprinted with permission from Ref. [43]. Copyright 2009. Elsevier. 

Plasma treatment is one of most common and suitable surface modification techniques for polymeric materials. This treatment can selectively introduce certain functional groups at a polymer sur ce with little damage to the bulk of the polymer. However, it is known that a plasma-treated polymer surface loses its properties gradually with aging. One reasonable explanation for this phenomenon is that the nctional groups, introduced by plasma treatment, rotate or move away from the surface into the bulk. Thus the changing surface properties may reflect... 

A wide array of surface modification techniques, ranging from simple to sophisticated, wet to dry, and vacuum to nonvacuum, are available for a host of polymeric materials. They include plasma surface treatment laser surface treatment corona, flame, UV, ozone, UV/ozone, photochemical, photografting, chemical grafting, and chemical methods of stuface modification and modification of polyamide surfaces by microorganisms [7]. 

Based on the membrane surface properties and the HA properties, various researchers have attempted to change the membrane surface characteristics by surface modification. Different techniques have been performed, such as ion beam irradiation, plasma treatment, redox-initiated graft polymerization, photochemical grafting, and interfacial polymerization (IP). In this chapter, two surface modification techniques, IP and photochemical grafting, are discussed by means of experimental examples. The surface characteristics of the unmodified membrane and the modified membranes are studied and their relationships with irreversible fouling and NF performance are reported. 

Recently, surface modification techniques for polymer chains have progressed a great deal with the development of a new polymer synthesis method. In particular, surface-initiated atom transfer radical polymerization (SI-ATRP) is one of the most effective modification methods for preparing a well-defined dense polymer brush structure, or polymer brush, on solid substrates. Thus, a self-oscillating polymer brush prepared by SI-ATRP can be expected to create a novel self-oscillating surface with autonomous function, which will lead to potential applications in transporting systems for nanomaterials of flow control in microfluidics. 

Tambe NM. Surface modification techniques for polymeric biomaterials for use as tissue engineering scaffolds. MS Thesis, North Carolina State University, Raleigh, USA, August 2011. 

Abstract Surface properties are a critical aspect of textiles for medical applications. This chapter discusses some popular surface modification techniques plasma activation, plasma polymerization, chemical grafting, and polymer encapsulation of nanoparticles. 

A comprehensive summary of the syntheses and applications of the ferrocene polymer brushes has been presented. Ferrocene-functionalized polymer brushes covalently bonded or physisorbed on solid substrate surfaces can be readily prepared via well-known surface modification techniques, such as surface-initiated polymerizations, reaction of the end-functional groups of polymer chains with substrate surfaces, and host-guest interaction. These electroactive polymer brushes have found applications in biosensors, anion-exchange chromatography, and redox-controlled modification of surface wetting properties. 

K. 2004. Novel surface modification techniques for polymer-based separation media Stimulus-responsive phenomena based on double polymeric selectors. ]mmwd olCh 1030 237-46. 

Figure 2 presents the most common plasma-based surface modification techniques for biomedical applications, described in more detail later plasma assisted chemical vapor deposition or PACVD (RF, MW), physical vapor deposition or PVD (sputtering, cathodic arc), plasma polymerization and grafting, plasma-based thermochemical treatments (e.g. plasma nitriding), ion implantation, plasma immersion ion implantation or PHI, and plasma spraying. Each technique has unique advantages and applications, and the choice of the more adequate technique often depends on the... 

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