Modification of graft surface

Modification of Graft Surface for Clot (Thrombus) Prevention... 

Modification of Polymer Surfaces by Photoinduced Graft Copolymerization... 

Two methods for modification of polymer surfaces by photoinitiated graft copolymerization have been developed a discontinuous method (1) with vapor phase transfer of initiator and monomer and a continuous method (2) with presoaking of a film strip or a fiber bundle in a solution of initiator and monomer. Both methods have been applied to polyelefins and linear polyester. 

Catalytic activity in olefin polymerization is related to the presence of cationic metal-hydrocarbyl species [90], which can be obtained by (i) using oxide supports that have high Br0nsted and Lewis acidity, (ii) the addition of a co-catalyst to a neutral supported species or (iii) modification of the surface with Lewis acid cocatalysts prior to grafting of the metal-hydrocarbyl species (Scheme 11.8a-c) [91-97]. 

Fig. 2 4-(4-(Norborn-5-ene-2-ylmethylenoxy)phenylethynyl)tolane-4 -thiol used as anchor group in a grafting-from approach to the surface modification of Au surfaces...

Modification of Collagenous Surfaces by Grafting Polymeric Side Chains to Collagen and Soft and Hard Tissues... 

The chemical modification of oxide surfaces with trialkynylorganotins 1 is not restricted to silica substrates. Indeed, nanoporous and nanocrystalline F-doped and undoped tin dioxide powders, prepared by a sol-gel route, 26 can be chemically modified with organotins la and Ic-d to provide fluorous or dye-sensitized Sn02 nanohybrids.2 27,28 for silica, the amount of deposited organic group progressively rises to a plateau value as the concentration of 1 in the grafting solution is increased (Table 3.2.2).22... 

We have also provided evidence that the behavior of microorganisms in confined micro-environment is substantially different and that their desired metabolic activities can be maximized through the modification of the surface characteristics as well as the size of the pores. These characteristics can therefore be utilized in BI as well as in the enhancement of cell penetration and cell proliferation in tissue engineering and when such polymers are grafted. Micro-fabrication technique has also been used in the development of highly porous catalysts with arterial channels feeding nano-pores which provide an extended surface area. Such materials can be used as micro-reactors as well as catalysts. 

The previously discussed principles of grafting-to and grafting-from can also be applied for the modification of polymer surfaces with polymer brushes. However, the binding of linkers and polymerization initiators to polymer surfaces is not as straightforward as it is for oxidic inorganic materials. Thus, dedicated pretreatments are usually necessary. These may include rather harsh reaction conditions due to the chemical inertness of many polymers (see Chapter 3). Alternatively, radiation treatment of polymers (to form radicals) followed by exposure to air may be used to form peroxides and hydroperoxides, which can be directly used as initiators for thermally or ultraviolet-induced graft polymerizations [16,17] (see Chapter 2). 

Recently, we explored strategies for binding spiropyran moieties to structured brushes grafted from ETFE and Teflon (PTFE) surfaces in order to obtain light-sensitive structured polymer surfaces [18]. We focused on post-polymerization modification of grafted brush structures because this strategy increases the flexibility with respect to the optimization of the concentration of spiropyran moieties in the brushes. Moreover, the tedious synthesis and purification steps of spiropyran—monomer conjugates are circumvented. 

Duebner M, Spencer ND, Padeste C. Light-responsive polymer surfaces via postpolymerization modification of grafted polymer-brush structures. Langmuir 2014 30(49) ... 

In recent years, many kinds of temperature-responsive PNIPAAm and its copolymer hydrogels with other acrylic monomers have been synthesized [142]. Besides being used for hydrogels, NIPAAm monomer can be grafted on to polymer substrates by electron beam, irradiation or UV-initiated graft polymerization to achieve special modification of polymer surfaces. Thus NIPAAm has been grafted on porous polymer films such as LDPE, PP, or polyamide films in order to prepare novel films for pervaporation of liquid mixtures or separation membranes [150,151]. 

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