Polymer Stereocomplexation as a Scalable Platform for Nanoparticle Assembly

DNA-mediated assembly of inorganic particles has demonstrated to be a powerful approach for preparing nanomaterials with a range of interesting optical and electrical properties. Building on this inspiration, we describe a generalizable gram-scale method to assemble nanoparticles through the formation of poly(methyl methacrylate) (PMMA) triple-helices. In this work, alkene-terminated syndiotactic (st-) and isotactic (it-) PMMA polymers were prepared and subsequently functionalized to afford nanoparticle ligands. Nanoparticles with complementary st- and it-PMMA ligands could then be spontaneously assembled upon mixing at room temperature. This process was robust and fully reversible through multiple heating and cooling cycles. The versatility of PMMA stereocomplexation was highlighted by assembling hybrid structures composed of nanoparticles of different compositions (e.g., Au and quantum dots) and shapes (e.g., spheres and rods). These initial demonstrations of nanoparticle self-assembly from inexpensive PMMA-based materials present an attractive alternative to DNA-based nanomaterials.

Conjugate substitution and addition of α-substituted acrylate: a highly efficient, facile, convenient, and versatile approach to fabricate degradable polymers by dynamic covalent chemistry

Degradable poly(conjugated ester)s with various backbones were synthesized via conjugate substitution (S_N2′) polymerization of bis[α-(chloromethyl)acrylate] and nucleophilic monomers under ambient conditions.

Synthesis of Isotactic-block-Syndiotactic Poly(methyl Methacrylate) via Stereospecific Living Anionic Polymerizations in Combination with Metal-Halogen Exchange, Halogenation, and Click Reactions

Isotactic (it-) and syndiotactic (st-) poly(methyl methacrylate)s (PMMAs) form unique crystalline stereocomplexes, which are attractive from both fundamental and application viewpoints. This study is directed at the efficient synthesis of it- and st-stereoblock (it-b-st-) PMMAs via stereospecific living anionic polymerizations in combination with metal-halogen exchange, halogenation, and click reactions. The azide-capped it-PMMA was prepared by living anionic polymerization of MMA, which was initiated with t-BuMgBr in toluene at ⁻78 °C, and was followed by termination using CCl₄ as the halogenating agent in the presence of a strong Lewis base and subsequent azidation with NaN₃. The alkyne-capped st-PMMA was obtained by living anionic polymerization of MMA, which was initiated via an in situ metal-halogen exchange reaction between 1,1-diphenylhexyl lithium and an α-bromoester bearing a pendent silyl-protected alkyne group. Finally, copper-catalyzed alkyne-azide cycloaddition (CuAAC) between these complimentary pairs of polymers resulted in a high yield of it-b-st-PMMAs, with controlled molecular weights and narrow molecular weight distributions. The stereocomplexation was evaluated in CH₃CN and was affected by the block lengths and ratios.

Anionic polymerization of ethyl acrylate initiated by tetrabutylammonium azide: direct synthesis of end-clickable polyacrylate

Tetrabutylammonium azide, a weak nucleophile, was found to initiate the living anionic polymerization of ethyl acrylate in the presence of alkylaluminum bisphenoxides as monomer activators to afford clickable azide-end polymers.

Polymerization of α-(halomethyl)acrylates through sequential nucleophilic attack of dithiols using a combination of addition–elimination and click reactions

Polycondensation involving sequential nucleophilic attacks of a dithiol on an α-(bromomethyl)acrylate efficiently yielded a polysulfide.

Structure-controlled polymers prepared by pseudo-living addition-condensation polymerization and their application to light harvesting

An A,B-block amphiphilic polymer and a branched polymer were prepared by using a new type of pseudo-living addition-condensation polymerization. The first polymer showed an interphase photoinduced energy transfer in a micellar system, while the second type showed efficient light-harvesting ability.

Stereoregular poly(methyl methacrylate) with double-clickable ω-end: synthesis and click reaction

Stereoregular PMMAs carrying an orthogonally double-clickable end, for thiol–ene and azide–alkyne cycloadditions, were prepared via termination with propargyl α-(chloromethyl)acrylate.

α-(Aminomethyl)acrylate: polymerization and spontaneous post-polymerization modification of β-amino acid ester for a pH/temperature-responsive material

Radical polymerizations of α-(aminomethyl)acrylates involved spontaneous post-polymerization modification triggered by breaking of the hydrogen bond and afforded pH/temperature responsive polymers.