Designing and fabricating multifunctional microcapsules are of considerable interest to both academic and industrial research aspects. This work reports an innovative approach to fabricate composite capsules with high UV and ultrasound responsive functionalities that can be used as external triggers for controlled release, yet with enhanced mechanical strength that can make them survive in harsh environment. Needle-like TiO 2 nanoparticles (NPs) were produced in situ into layer-by-layer (LbL) polyelectrolyte (PE) shells through the hydrolysis of titanium butoxide (TIBO). These rigid TiO 2 NPs yielded the formed capsules with an excellent mechanical strength, showing a free standing structure. A possible mechanism is proposed for their special morphology formation of the TiO 2 NPs and their reinforce effects. Synergistically, their response to UV and ultrasound was visualized via SEM, with results showing an irreversible shell rapture upon exposure to either the UV or ultrasound irradiation. As expected, the release studies revealed that the dextran release from the TiO2/PE capsules was both UV-dependent and ultrasound-dependent. Besides, biocompatibility of the capsules with the incorporation of amorphous TiO 2 NPs was confirmed by MTT assay experiment. All of these evidences suggested a considerable potential medicine application of the TiO 2 /PE capsules for controlled drug delivery.

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The efficiency of the magnetic refrigeration process strongly depends on the heat transfer performance of the regenerator. As a potential way to improve the heat transfer performance of a regenerator, the design of sub-millimeter hydraulic diameter porous structures is realized by freeze-cast structures. Four freeze-cast regenerators with different pore widths are characterized experimentally and numerically. Empirical parameters are determined for the correlations of heat transfer and flow resistance via a 1D model. Thermal effectiveness and pressure drop are measured for thermal-hydraulic evaluations. Temperature span and specific cooling capacity are obtained to compare the magnetocaloric potential based on the material La0.66Ca0.27Sr0.06Mn1.05O3. The stability of freeze-cast regenerators is validated by comparing the performance during, before and after oscillatory flow and periodic magnetic field tests. Smaller pore design obtain the better heat transfer performance and required mechanical strength, while pore design with significant dendrites provides the worst tradeoff between heat transfer performance and flow resistance.