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.

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In the present study, special effort was focused on increasing permeability of matrimid membranes. For this objective, a bromination reaction was carried out. The reaction of bromine with polymer was investigated using Fourier transform infrared (FTIR) spectroscopy analysis. A combination of pristine and brominated matrimid was used to prepare modified membranes due to the fact that brominated matrimid membranes were too delicate. Employing a gas separation membrane unit, the permeability of pristine and modified membranes for pure gases (CO2 and CH4) was studied. Modified membranes were much more permeable and less selective than pristine membranes. In fact, the increase in permeability of modified membranes can be attributed to the rise in the fractional free volume of modified membranes. Thermal properties of modified and unmodified membranes were also studied by thermal gravimetric and differential scanning calorimetry analysis. As a result, thermal resistance of modified membranes decreased in a limited temperature range. Modified membranes indicated smaller values of tensile strength than pristine membranes which were assessed using tensile strength analysis. The parameters which can affect the pure gases permeation through membranes such as, bromine concentration in modified membranes and operating pressure were considered as variables and the experimental design was carried out.