Surface-initiated ROMP

Recently, Caster et al. described the surface modification of multifilament fibers such as nylon or Kevlar [70]. Coating techniques using preformed ROMP-based polymers and process contact metathesis polymerization (CMP), initially described by Grubbs et al. [71], were both used. The latter involves a procedure where the initiator is physisorbed onto the surface of a substrate and fed with a ROMP-active monomer that finally encapsulates the substrate. These modified fibers showed improved adhesion to natural rubber elastomers. 

In the case of capillary columns, in the initial step of preparation the surface is modified with bicyclo[2.2.1]hept-2-en-5-ylmethyldi-chlorosilane. This acts as an anchor for subsequent ROMP polymerization. Some functional monomers used for monolith grafting are shown in Figure 1.13. 

The multifunctional initiator approach was also used for the synthesis of stars by ROMP. Carbosilane dendrimers bearing mthenium complexes on their surface (Scheme 59) were prepared and used to synthesize 4- and 8-arm polynorbomene stars. End-group analysis by NMR revealed that well-defined stmctures were obtained. 

In direct write lithography, a tip can be used to pattern a surface and prepare polymeric nanostructures. Polymerization is initiated by the tip and a pattern is formed. Polymer brush nanostructures can be synthesized using ring opening metathesis polymerization (ROMP). Edge distances of less than 100 nm are possible, and control over feature size, shape, and interfeature distance is achievable. 

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