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

Wei-Cheng Chen,Lizong Dai,Tao Chen,Shiao-Wei Kuo,Yu-Hsuan Tsao,Chih-Feng Wang,Chih-Feng Huang

doi:10.3390/polym12020465

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.

Highlights

The self-assembled nanostructures that form from immiscible diblock copolymers (BCPs) have received much attention because of their potential applications in, for example, nano-patterning, drug delivery, and photonic crystals [1,2,3,4,5]
Positioning hydrogen bond donor or acceptor units into the block segments can alleviate macrophase separation in diblock copolymer mixtures; many experimental and theoretical studies have been undertaken into the preparation of such block copolymer/homopolymer and block copolymer mixtures [10,11,12,13,14,15,16,17,18]
The incorporation of inorganic nanoparticles into self-assembled BCPs in the form of block copolymer/nanoparticle (BCP/NP) composites, with the blends stabilized through specific interactions, has potential applications in nanodevices, photonics, and sensors [19,20,21,22,23]

Summary

Introduction

The self-assembled nanostructures (e.g., cylindrical, lamellar, spherical, and double-gyroid structures) that form from immiscible diblock copolymers (BCPs) have received much attention because of their potential applications in, for example, nano-patterning, drug delivery, and photonic crystals [1,2,3,4,5]. The incorporation of inorganic nanoparticles into self-assembled BCPs in the form of block copolymer/nanoparticle (BCP/NP) composites, with the blends stabilized through specific interactions, has potential applications in nanodevices, photonics, and sensors [19,20,21,22,23]. Functionalized POSS NPs have been prepared with one, two, or eight functionalized units; we have discussed their effects on the self-assembled structures of BCP hybrid complexes in several previous reports [30,31,32]. The number of phenolic functionalities of a POSS NP strongly affects the self-assembled structures formed when blended with poly (styrene–b–4-vinylpyridine) (PS-b-P4VP)

Methods

Results

Conclusion