One‐Step Synthesis of Biphasic, Cavity‐forming Polymer Particles via Dispersion Copolymerization of Styrene and Sulfobetaine Methacrylate. Issue 7 (15th February 2023)

• Record Type: Journal Article
• Authors: Hamilton, Heather S.C.; Meissner, Cornelia; Emrick, Todd; Bradley, Laura C.
• Is Part Of: Macromolecular rapid communications. Volume 44:Issue 7(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-02-15
• Subjects: dispersion copolymerization -- heterogeneous polymerization -- polymer colloids -- polyzwitterions; Macromolecules -- Periodicals; Polymers -- Periodicals; Chemistry -- Periodicals; 547.705
• DOI: 10.1002/marc.202200873
• Languages: English
• ISSNs: 1022-1336

Abstract

Abstract: A one‐step dispersion copolymerization technique is demonstrated to fabricate biphasic particles as an approach to streamline the production of particles with complex morphology. The model system studies a monomer feed of hydrophobic styrene and hydrophilic, zwitterionic sulfobetaine methacrylate (SBMA) in a water/isopropanol cosolvent mixture. The resulting particles have a core–shell morphology that can be transformed, simply by washing the particles with water, into particles with a single surface opening connected to an interior cavity. Results indicate that particle morphology is dependent on the presence of nanoscopic SBMA‐rich aggregates in the initial reaction mixture to act as nucleation sites, forming an SBMA‐rich core encased in a styrene‐rich shell. Systematic study of the morphology evolution reveals that the difference in monomer solubility profile can be exploited to control compositional drift of the particle composition during copolymerization yielding copolymer with sufficiently different composition to form phase‐separated particle morphology. When SBMA is replaced with various ionic comonomers, the cavity‐forming morphology is observed when reaction conditions result in low solubility of the comonomer in the cosolvent mixture. Based on these results, design guidelines are developed that may be applied to a variety of systems requiring complex and responsive particles made from chemically distinct comonomer pairings. Abstract : Biphasic cavity‐forming zwitterionic colloids are synthesized using a one‐step technique developed from dispersion copolymerization principles. The sub‐micron‐sized biphasic particles have a core–shell morphology that can be easily transformed by extraction of the hydrophilic zwitterionic core, using only water, to yield cavity‐containing particles. Monomer solubility in the reaction medium is shown to be a key parameter governing morphology formation.