Fabrication of Hollow Polystyrene Nanospheres in Microemulsion Polymerization Using Triblock Copolymers

Abstract

A ternary microemulsion polymerization was successfully used to prepare nanosized hollow polystyrene (PS) microlatexes with triblock copolymers of poly(oxyethyene)−poly(oxypropylene)−poly(oxyethylene)[(EO) x (PO) y (EO) x ]. Micelle formation using triblock copolymers is a useful nanoreactor in order to make polymer nanoparticles in oil/water (o/w) microemulsions. Poly(methyl methacrylate)/cross-linked polystyrene core/shell nanospheres have been fabricated by o/w microemulsion. PS hollow nanospheres were obtained using the polymer core etching technique. Water-soluble and oil-soluble initiators were used for the polymerization at 70 °C with moderate stirring and via modified buret feeding. After extraction of the surfactant matrix, the polymer particles contract considerably without the change of their spherical shape. The hollow sphere morphology and hollow image of the polymer particles were confirmed by field emission scanning electron microscope and transmission electron microscope. PS hollow spheres were fabricated with diameters in the range of ca. 15−30 nm, and the shell thickness was ca. 2−5 nm. The size of the hollow nanoparticle is dependent on the surfactant concentration and the weight ratio of [surfactant]/[monomer].

Self‐Assembled Nanoreactors

“…Jang and Ha have used poly-(oxyethylene)-b-poly(oxypropylene)-b-poly(oxyethylene) to make hollow polystyrene nanospheres. 255 Mini-emulsion polymerization has also proven to be a valuable tool for the fabrication of polymeric capsules. 256 Mini-emulsions are stable emulsions consisting of droplets of 50-500 nm in diameter created by shearing a mixture of oil, water, surfactant, and a highly hydrophobic compound.…”

Direct Preparation of Hollow Nanospheres with Kraft Lignin: A Facile Strategy for Effective Utilization of Biomass Waste

“…Because they can encapsulate guest molecules in their interior, hollow spheres have great potential for applications such as drug storage and delivery (Kataoka et al 2012), separation (Wang et al 1998), adsorbents, microreactors (Vriezema et al 2005), catalysts (Lu et al 2015), supercapacitors (Liu et al 2014), and medical examination and diagnosis (Salata 2004). Methods for the fabrication of hollow spheres have been extensively reported, including template synthesis (Liu and Basu 2009), self-assembly (Breitenkamp and Emrick 2003), emulsion polymerization (Jang and Ha 2002), core removal of dendrimers (Zimmerman et al 2002), and direct polymerization reaction (Kim et al 2010); however, the most commonly used raw materials are synthetic polymers.…”

Selective Fabrication of Poly(3,4‐ethylenedioxythiophene) Nanocapsules and Mesocellular Foams Using Surfactant‐Mediated Interfacial Polymerization

“…No products are obtained with Pluronic P123 (a poly(ethylene oxide) (PEO)/poly(propylene oxide) (PPO) block copolymer, PEO 20 PPO 70 PEO 20 , a non-ionic surfactant) because electrostatic interactions are absent and diffusional degradation of the micelles might occur upon the sudden addition of cyclohexane, in which the solubility of Pluronic P123 is very limited (less than 10 -3 wt.-%). [11] PEDOT nanoparticles with diameters of 30-100 nm were exclusively produced with sodium dodecyl sulfate (SDS, an anionic surfactant). [12] In this case, it is believed that the polymerization occurs inside the micelles; the initiator tends to be located within the micelles due to its affinity for the surfactant spacer groups.…”