Main Chain–Type Block Copolymers through Atom Transfer Radical Polymerization from Double-Decker–Shaped Polyhedral Oligomeric Silsesquioxane Hybrids

Abstract

In this study, we synthesized two main chain–type block copolymers featuring hydrogen bond donor and acceptor segments through atom transfer radical polymerization (ATRP) using a bifunctionalized polyhedral oligomeric silsesquioxane (POSS) nanoparticle as the initiator. Hydrosilylation of vinylbenzyl chloride at the two corners of a double-decker silsesquioxane (DDSQ) provided the bifunctionalized benzyl chloride initiator VBC-DDSQ-VBC, which we applied as a platform to prepare a main chain–type polystyrene homopolymer (PS-DDSQ-PS), the diblock copolymer poly(styrene–b–4-vinylpyridine) (P4VP-b-PS-DDSQ-PS-b-P4VP), and the diblock copolymer poly(styrene–b–tert-butoxystyrene) (PtBuOS-b-PS-DDSQ-PS-b-PtBuOS) through sequential ATRP. Selective hydrolysis of the tert-butoxyl units of PtBuOS-b-PS-DDSQ-PS-b-PtBuOS yielded the strongly hydrogen bonding diblock copolymer poly (styrene-b-vinylphenol) (PVPh-b-PS-DDSQ-PS-b-PVPh). We used Fourier transfer infrared spectroscopy, nuclear magnetic resonance spectroscopy, size exclusion chromatography, differential scanning calorimetry, mass-analyzed laser desorption ionization mass spectrometry, and transmission electron microscopy to investigate the chemical structures, thermal behavior, and self-assembled nanostructures formed by these main chain–type block copolymers based on DDSQ.

Multifunctional Polyhedral Oligomeric Silsesquioxane (POSS) Based Hybrid Porous Materials for CO2 Uptake and Iodine Adsorption

“…Polyhedral oligomeric silsesquioxanes (POSSs) are a kind of nanostructured compound with a diameter in the range of 1–3 nm, an empirical formula ( R 8 Si 8 O 12 ), a well-defined structure, and a controlled porosity [ 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 ]. Recently, using an inorganic POSS as a building block for preparation, hybrid porous materials have attracted much attention because of their excellent thermal and mechanical proprieties, water retardance, and chemical stability [ 62 , 63 , 64 , 65 , 66 ].…”

Unconventional Conjugation via vinylMeSi(O−)2 Siloxane Bridges May Imbue Semiconducting Properties in [vinyl(Me)SiO(PhSiO1.5)8OSi(Me)vinyl-Ar] Double-Decker Copolymers

“…Polysilsesquioxanes, [RSiO 1.5 ] n , have received extensive attention because of their high thermal stability coupled with facile chemical modification that offers potential utility in multiple applications ranging from low- k interlayer dielectrics, to nanoimprint lithography, to mechanically hard, thermally stable, scratch resistant transparent coatings. − The majority of these applications rely on 3D networks often generated by hydrolysis of mixtures of RSi­(OEt) 3 /R′Si­(OEt) 3 , for example, wherein the intermediates are coated or cast onto substrates and then heated to promote cross-linking through condensation coincident with elimination of water. − Alternately, one can functionalize [RSiO 1.5 ] 8,10,12 cages with reactive groups and copolymerize them by reaction with di-, tri-, and so on functional organic groups to produce 3D structures that often offer gel-like properties. ,, …”

“…Linear format polysilsesquioxanes can also be synthesized. The most common forms consist of traditional polymer backbones wherein the SQ is a pendant group. ,, A much rarer form begins with SQ’s functionalized ≥2 times such that the functional groups can be copolymerized with difunctional organic monomers. ,− Recently, the discovery of a way to make difunctional phenylsilsesquioxanes, often called double-decker (DD) cages, has led to a significant number of contributions wherein the SQ cage is part of the polymer backbone and to materials with many of the above-mentioned properties but that are now relatively easily processed; see Figure . ,− …”

Polyphenylsilsesquioxanes. New structures–new properties

“…Such functional p-PPSQ are widely used in polymer chemistry and in materials science. [92][93][94][95][96][97][98][99][100][101]…”