(188r) Preparation and Characterization of PNIPAΜ/Alginate Microcapsules

Thermo-responsive microcapsules consisted of poly(N-isopropylacrylamide) (PNIAPM) and alginate were prepared using concentric two-fluid nozzle. In this method, PNIPAM and alginate were used as thermo-responsive polymer and structure support polymer, respectively. In the experiment, the shell material solution which contained NIPAM monomer, cross-linking agent and sodium alginate was pumped out from outer nozzle, and the core material solution which contained cocoa particles as marker was pumped out from inner nozzle of the centric two-fluid nozzle to form droplets of double layered structure. When the droplets were dripped into the gelator solution which contained polymerization initiator, accelerator and calcium chloride, shell material solution was transformed into the hydrogel and capsules were formed. The result showed that the obtained capsules had complex structure of PNIPAM gel and calcium alginate gel. The capsules demonstrated thermo-responsive volume change such that swollen at low temperature and shrunk at high temperature. The volume change of the capsules was affected by NIPAM monomer concentration and polymerization initiator concentration. The result suggests that the extent of the volume change can be controlled by changing NIPAM monomer and/or polymer initiator concentration.