Stereoregular Polymerization within Template Nanospaces

Abstract

ABSTRACT:Highly efficient stereoregular polymerizations within template nanospaces using free radical initiators, based on stereocomplexes formed between isotactic and syndiotactic methacrylate polymers are reviewed. Ultrathin films composed of double-stranded helical or van der Waals contacted stereocomplex nanostructures were successfully prepared by the layer-by-layer assembly method, and fundamental aspects of film preparation were summarized. Template nanospaces were prepared by the selective solvent extraction of a single component from stereocomplex films composed of it-poly(methyl methacrylate) and st-poly(methacrylic acid). The resulting porous films with designed nanospaces were used for template polymerizations. Methacrylate polymers with high iso-and syndiotacticities were synthesized within nanospaces. Structural information not only of template stereoregularity but also of template chain length was efficiently transferred to synthesized polymers.

Stereospecific Living Radical Polymerization: Dual Control of Chain Length and Tacticity for Precision Polymer Synthesis

“…More recently, an excellent study on stereocomplex-induced template polymerization was reported by Akashi and Serizawa et al, in which macromolecularly porous ultrathin films fabricated by layer-by-layer assembly were used as the template for the highly efficient stereoregular template polymerization of MMA or MAA. [206][207][208] Highly stereospecific propagation could occur in the pores, which were prepared by the alternative layer-by-layer assembly of isotactic poly(MMA) and syndiotactic poly(MAA), followed by the extraction of one component from the thin film ( Figure 10). In addition to the stereoregularity, the molecular weights of the resulting polymers were also well controlled, which were based on a double-or triple-stranded helical stereocomplex formed between the isotactic and syndiotactic polymers (1:2 in length/length), though the molecular weight distributions became broader.…”

Effects of Ionization on Tacticity and Propagation Kinetics in Methacrylic Acid Polymerization

“…However, many of these approaches are difficult and expensive to implement, while others have a relatively narrow scope or are simply unable to replicate the high stereoselectivity that can be achieved in contemporary anionic and coordination polymerization. Some of the most effective (and elegant) strategies, such as stereoregular templating (2)(3)(4), are impractical and could not be readily applied to grams scale polymer synthesis. The strategy that is best able to balance the competing demands of effectiveness and practicality is monomer modification to incorporate bulky (5)(6)(7)(8), chiral (9,10) and ionic auxiliaries (11)(12)(13)(14)(15)(16)(17)(18)(19)(20).…”

Stereospecific living radical polymerization for simultaneous control of molecular weight and tacticity

“…Another solution is the use of a specific confined reaction space that can isolate and fix the growing radical species for the stereospecific chain growth without suffering from the bimolecular radical-radical termination. 57,58 No one could predict the recent and significant developments in radical polymerizations 10 years ago, but now one can hope for future wide developments not only in more controlled radical polymerizations in terms of molecular weights, stereoregularity, and monomer sequence, but in material design based on the well-constructed polymer structures.…”