Chlorosilanes structural parameters

An alternative route for the preparation of styrenic macromonomers is the reaction of living chains with 4-(chlorodimethylsilyl)styrene (CDMSS) [192]. The key parameter for the successful synthesis of the macromonomers is the faster reaction of the living anionic chain with the chlorosilane group rather than with the double bond of the CDMSS. Anionic in situ copolymerization of the above macromonomers (without isolation) with conventional monomers leads, under appropriate conditions, to well-defined comb-like chains with a variety of structures. 

An alternative approach concerns the preparation of multilayer films in which each layer has different refractive indexes. Li et al. [107] fabricated multilayers with an increasing refractive index from the top to the bottom of the film. They prepared blends of BCP/homopolymers (PS-b-PMMA/PMMA). They used an octadecyltri-chlorosilane-modified glass substrate, and a mixture of solvents made the PMMA domains form a gradient distribution in the vertical direction of the entire micro-phase-separated film. This unique behavior allows, upon removal of PMMA, to obtain porous PS-based structures with variable porosity in the vertical direction (Fig. 6.17). Later, the authors investigated further the parameters [total degree of polymerization (AO, the volume fraction of the PMMA block (/pmma). the weight percentage of the homopolymer, and the solution concentration] that direct the structure formation and related them with the broadband antireflection properties [108]. 

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