No abstract

A route of synthesizing triblock terpolymers in a one-pot, "one-step" polymerization approach is presented. The combination of two distinct polymerization techniques through orthogonal catalyst/initiator functionalities attached to a polymeric linker furnishes novel pathways to ABC-terpolymers. Both polymerizations have to be compatible regarding mechanisms, chosen monomers, and solvents. Here, an α,ω-heterobifunctional poly(ethylene glycol) serves as poly-meric catalyst/initiator to obtain triblock terpolymers of poly(norbornene)-b-poly(ethylene glycol)-b-poly(L-lactic acid) PNB-PEG-PLLA via simultaneous ring opening metathesis poly-merization and ring opening polymerization in a fast one-pot polymerization. Structural characterization of the polymers is provided via (1)H-, DOSY-, and (1)H,(1)H-COSY-NMR, while solution and thin film self-assembly are investigated by dynamic light scattering and atomic force microscopy.

Porous hollow silica particles (HSPs) are presented as new templates to control the product morphology in metallocene-catalyzed olefin polymerization. By selectively immobilizing catalysts inside the micrometer-sized porous hollow silica particles, the high hydraulic forces resulting from polymer growth within the confined geometries of the HSPs cause its supporting shell to break up from the inside. As the shape of the support is replicated during olefin polymerization, perfectly spherical product particles with very narrow size distribution can be achieved by using HSPs exhibiting a monomodal size distribution. Furthermore, the size of the obtained product particles can be controlled not only by the polymerization time but also by the size of the support material.

Front Cover: Hollow silica particles (HSPs) act as supports for metallocene catalysts to enable ethylene polymerization within their confined geometries. Selective catalyst immobilization inside these uniform HSPs allows for controlled polymer growth and results in spherical polyethylene particles with monomodal size distribution. The fragmented silica shell on the outside, caused by hydraulic forces from polymer growth, can be evidenced microscopically. Further details can be found in the article by I. Freudensprung, D. Joe, S. Nietzel, D. Vollmer, M. Klapper,* and K. Müllen on page 1651.