Porous Polystyrene Monoliths and Microparticles Prepared from Core Cross-linked Star (CCS) Polymers-Stabilized Emulsions

Abstract

A hydrophobic CCS polymer of poly(benzyl methacrylate) (PBzMA) was prepared in toluene by reversible addition-fragmentation chain transfer (RAFT)-mediated dispersion polymerization. The CCS polymer, with poly(benzyl methacrylate) as the arm and crosslinked N, N′-bis(acryloyl)cystamine (BAC) as the core, was confirmed by characterization with gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) spectroscopy. Three kinds of oils (toluene, anisole and styrene) were chosen to study the emulsification properties of PBzMA CCS polymer. The oils can be emulsified by CCS polymer to form water-in-oil (w/o) emulsions. Moreover, w/o high internal phase emulsions (HIPEs) can be obtained with the increase of toluene and styrene volume fractions from 75% to 80%. Porous polystyrene monolith and microparticles were prepared from the emulsion templates and characterized by the scanning electronic microscopy (SEM). With the internal phase volume fraction increased, open-pore porous monolith was obtained.

Rapid and Highly Controlled Generation of Monodisperse Multiple Emulsions via a One-Step Hybrid Microfluidic Device

“…Several different materials have been employed to constitute different phases of MEs to enhance emulsion stability and protect inner droplets against flocculation, creaming, or coalescence 20 . These materials include but not limited to liquid crystals 21–23 and lecithin 24 ; synthesized graphene oxide-polystyrene 25 ; glycerol to produce polyols-in-oil-in-water 26 ; natural glycyrrhizic nanofibrils assembling into a fibrillary hydrogel network to produce gelled MEs 20 ; bioactive materials dispersed in glycerol with the components of glycerol and organogel matrix of sitosterol-oryzanol in sunflower oil gels to produce oleogel capsules 27 ; graphene micro-aerogels embedded within soft MEs for electrochemical sensing 28 ; mix of oil, toluene, water and microparticles of poly benzyl methacrylate to produce porous polystyrene monoliths MEs 29 ; short-chain fatty acid within dietary fibers MEs 30 ; bacterial celluloses encapsulated within protein and polyglycerol polyricinoleate MEs 31 ; and eucalyptus oil, ubiquinone and fine water interfacing with hydroxy methyl cellulose and tannic acid to produce soft microcapsules of MEs 32 . Also, several emulsifiers 33 , silica nanoparticles 34–37 , colloidal materials 8,38,39 , pH stimuli-responsive polymers 40,41 , biomacromolecules 42 , surfactants 43,44 and physical parameters 45,46 have been incorporated to improve the MEs stability and performance 8,39,47–49 .…”

A new approach to produce polystyrene monoliths by gelation and capillary shrinkage

“…A bulk material rather than a powder is preferred for many material applications especially when used as a support or matrix, since it takes full advantage of the mechanical stability and easy reuse [1]. Polystyrene (PS) is a common polymer and has been widely used in many fields, such as plastic products, insulation materials, catalyst supports, chromatographic separation, gas or oil absorption [2][3][4][5][6][7][8]. Like many thermoplastics, extrusion, compression or injection molding is usually used for shaping PS in industry, but many attempts have been made to produce a functional polymeric monolith without complex shaping equipment and high energy consumption.…”

Magnetothermally Activated Nanometer-level Modular Functional Group Grafting of Nanoparticles

“…The core@shell MNPs are known to exhibit sufficient heating power to generate a polymeric shell on the surface of the nanoparticle, while suppressing bulk heating . AIBN with an activating temperature of 60 °C was used as an initiator for radical polymerization. − The mechanically stirred mixture was then subjected to an alternating magnetic field (AMF) of 40 mT at 500 kHz for 10 min. This resulted in the formation around each nanoparticle of an approximately 1 nm thick PVP coating layer with a highly monodispersed size distribution (σ ∼ 8%).…”