title: Environmentally responsive core/shell particles via electrohydrodynamic co-jetting of fully miscible polymer solutions.
abstract: Herein it is demonstrated that electrohydrodynamic co-jetting is not limited to Janus-type particles, but can also be used for the preparation of core/shell particles. Using side-by-side flow of miscible polymer solutions, electrohydrodynamic co-jetting offers an elegant and scalable route towards preparation of core/shell particles with otherwise difficult-to-prepare particle architectures, including particles with hydrophilic shell and core. Throughout this study, electrohydrodynamic co-jetting of aqueous solutions consisting of a mixture of PAAm-co-AA and PAA is used, and a range of different types of particles with distinct compartments are observed. Transition from Janus particles to core/shell particles appears to be caused by changes in the relative conductivity of the two jetting solutions. After crosslinking, the core/shell particles are stable in aqueous solution and exhibit reproducible swelling behavior while maintaining the original core/shell geometry. In addition, the pH-responsiveness of the particles is demonstrated by repeatedly switching the environmental pH between 1.3 and 12. Moreover, the core/shell particles show surprising uptake selectivity. For instance, a 450% increase in uptake of 6-carboxyfluorescein over rhodamine B base is found.
authors.affiliation: Departments of Chemical Engineering and Materials Science, The University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Abbass
authors.initials: A
authors.lastname: Kazemi
authors.forename: Joerg
authors.initials: J
authors.lastname: Lahann
mesh_terms: D004396:Coloring Agents; D004553:Electric Conductivity; D004777:Environment; D006863:Hydrogen-Ion Concentration; D018613:Microscopy, Confocal; D008863:Microspheres; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D011108:Polymers / Q000737:chemistry*; D012996:Solutions
chemical_list: D004396:Coloring Agents; D011108:Polymers; D012996:Solutions