Helix-sense-selective polymerizations (HSSPs) have been attracting much attention for controlling the chirality of synthetic helical polymers. However, up to date HSSPs have provided only optically active helical polymer solutions and emulsions. The present contribution reports on the first HSSPs for directly constructing optically active physical gels (OAPGs) by using achiral substituted acetylene monomer with (R)- or (S)-1-phenyl­ethylamine as chiral additive. The one-handed helical conformations of the resulting polymers and the optical activity of the gels thereof were verified by CD and UV–vis absorption spectra. SEM images show that the OAPGs were constructed by helical nanofibers with remarkable one-handed screw sense. After complete removal of the chiral additive, the purified OAPGs and the polymers forming the gels still showed intense CD signals, demonstrating their excellent chiral memory ability. This significant advantage and the simple preparative methodology endow the OAPGs with great potentials as chiral functional materials.

Optically active polymer particles constitute a unique type of polymer particle. However, nearly all the particles of this kind so far reported in the literature were prepared from chiral monomers. On the other hand, helix-sense-selective polymerization (HSSP) techniques were majorly applied in solution polymerization systems for preparing helical polymers adopting predominant onehanded helicity. In the present study, we report the first HSSP in precipitation polymerization systems, by which optically active helical polymer particles were constructed from an achiral monomer. Achiral acetylenic monomer with bulky adamantyl group smoothly underwent helix-sense-selective precipitation polymerization (HSSPP) with (nbd)Rh + B − (C 6 H 5 ) 4 as catalyst in the presence of Boc-L-or Boc-D-alanine as chiral additive. The HSSPPs provided optically active polymer particles consisting of helical polymer forming predominantly one-handed screw sense. SEM images show that the resulting polymer particles were obtained in high yield (80 wt %, average diameter approximately 300 nm) with regular spherical morphology. CD spectra clearly demonstrated that HSSP occurred in the course of precipitation polymerizations. The induced helical structures with preferential screw sense exhibited relatively high thermostability. We further proposed a possible mechanism for the occurrence of HSSPPs and the formation of stable helical structures: Double hydrogen bonds formed between each chiral additive molecule and the neighboring two amide structures in the polymer pendant groups; the double hydrogen bonds played essential roles for controlling the screw sense of the helical polymer chains and the stability. Based on this mechanism, a "chiral-lock effect" was further put forward. The preparative strategy opens new routes for preparing optically active polymer particles and even novel superhelical architectures for significant uses as chiral stationary phase for HPLC, chiral catalysts, enantioselective recognition probes, etc.

How to prepare polymeric particles from acetylene and its derivatives, in particular in aqueous media, has remained as a challenging research topic for a rather long period. In recent years, this research area has achieved exciting progress and a variety of novel functional particles have been reported. However, there has not yet a review article exclusively summarizing the progress. This article presents an overview on the advanced particles with emphasis on the preparation and their applications. The state-of-the-art preparation methods fall into two major groups: emulsion, precipitation, suspension polymerization approaches by starting from monomers; and post-treatment of 10 pre-formed polymers (i.e. self-assembly). The polymer particles were investigated in such applications as circuits, sensors, drug release and chiral-related processes for instance asymmetric catalysis, enantioselective crystallization, enantioselective release, amongst many others. The review article is expected to stimulate more unprecedented functional particles derived from acetylene and its derivatives.

Polymer Janus particles (PJPs) have been extensively investigated due to their intriguing features which cannot be achieved in traditional counterparts. Chiral polymer particles also have constituted a unique research area in polymer science. However, how to construct PJPs derived from chiral polymers, especially chiral helical polymers, still remains a significant academic challenge. This contribution reports the first success in preparing optically active PJPs constructed by chiral helical substituted polyacetylene via emulsion polymerization combined with solvent evaporation to induce phase separation. In emulsion polymerization systems, polymethyl methacrylate worked as a template and separated from polyacetylene domains in the course of acetylenic monomers’ polymerization and evaporation of the solvent, by which optically active PJPs were formed. The major influencing factors were explored to elucidate their effects on the formation and morphology of PJPs. Mushroom- and bowl-like PJPs were obtained. Scanning electron microscopy (SEM) images ascertain nonspherical morphologies of the obtained PJPs. Circular dichroism and UV–vis absorption spectra demonstrate their optical activity, which originated in the predominantly one-handed helical polyacetylene chains constructing the PJPs. A formation mechanism was then proposed for understanding this unprecedented type of PJPs.

This article reports the first fluorescent microparticles (MPs, approximately 600 nm in diameter) constructed using helical substituted polyacetylene and prepared via a precipitation polymerization approach. The MPs judiciously combine this interesting helical conjugated acetylene, fluorescent material and polymeric particles in one entity. The monomer containing a dansyl group undergoes precipitation polymerization in butanone/n-heptane mixed solvent, with (nbd)Rh(+) B(-) (C6 H5 )4 as a catalyst. MPs with a regular morphology are formed in a high yield (>80 wt%). UV-vis spectroscopy demonstrates that the polymer chains making up the MPs adopt helical structures. The MPs show considerable fluorescence emission (λmax , 500 nm; excited at 340 nm). Based on SEM and fluorescence images, the formation mechanism of the MPs is proposed. This methodology opens up new ways to prepare functional microstructured materials derived from substituted polyacetylenes, and may also result in opportunities for new practical applications of polyacetylene and its derivatives.