Block copolymers lanthanide complexes

As described in Section 9.1.2.2.3, several lanthanocene alkyls are known to be ethylene polymerization catalysts.221,226-229 Both (188) and (190) have been reported to catalyze the block copolymerization of ethylene with MMA (as well as with other polar monomers including MA, EA and lactones).229 The reaction is only successful if the olefin is polymerized first reversing the order of monomer addition, i.e., polymerizing MMA first, then adding ethylene only affords PMMA homopolymer. In order to keep the PE block soluble the Mn of the prepolymer is restricted to <12,000. Several other lanthanide complexes have also been reported to catalyze the preparation of PE-b-PMMA,474 76 as well as the copolymer of MMA with higher olefins such as 1-hexene.477... 

Examples of such chemosensors have been outlined including oxygen (or air pressure), pH, humidity, hydrogen peroxide, copper, and temperature sensors. However, the encapsulation of lanthanide probes in sohd state matrices or polymer nano- or microparticles can contribute to reduce the impact of interfering agents. Many polymers provide a selective permeability and block certain species. A number of copolymers, particularly block copolymers, are available that on the one hand are well suited for the immobilization of lanthanide complexes, and on the other hand hinder the diffusion of certain interfering species into the layer. 

Figure 2. Block copolymer microphase separation with lanthanide complex at the block junction (lamellar morphology shown).

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