Stereocomplex Nanocomposite Switch Based on Dynamic Helical Polymer-Gold and Silver Nanoparticle Hybrid Materials

Controlled ON/OFFstereocomplexation of dynamic helical polymer-metalnanoparticle nanocomposites-poly(phenylacetylene)-MNP nanocomposites(M = Au or Ag)-is presented. These novel hybrid materials canbe found either as well-dispersed metal nanoparticles (MNPs) (stereocomplexOFF) or as fiber-like aggregates (stereocomplex ON) with the metalnanoparticles distributed along the material. A stereocomplex-MNPnanocomposite is formed by the interaction of two complementary andenantiomeric helical polymer-MNP nanocomposites [Poly-(R)-1-M(1)NPs/poly(S)-1-M(2)NPs (M-1 = M-2 or M-1 not equal M-2; M = Au, Ag)]. Interestingly, by usingdynamic helical polymers, i.e., poly(phenylacetylene)s (PPAs), ascoating agents of the metal nanoparticles, it is possible to tunethe secondary structure of the polymer-elongation and/or compression-afact that can trigger the formation/disruption of the stereocomplex.Moreover, the stereocomplexation of these nanocomposites can be controlledin a reversible way (ON/OFF) by playing with the supramolecular interactionsthat keep the two enantiomeric and complementary helices together,such as hydrogen bonds.

Automated summary

Controlled ON/OFF stereocomplexation of dynamic helical polymer-metal nanoparticle nanocomposites is achieved by using poly(phenylacetylene) (PPA) as the coating agent of metal nanoparticles. The materials can exist as dispersed metal nanoparticles (stereocomplex OFF) or fiber-like aggregates (stereocomplex ON), depending on the secondary structure of the polymer. The formation/disruption of the stereocomplex can be triggered by elongation and/or compression of the polymer, and the supramolecular interactions, such as hydrogen bonds, play a key role in the reversible control of stereocomplexation.