Thermal Tunning of Colloidal Array in Microcapsules from Crystalline to Glassy Packing
발표자
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초록
내용
Colloidal assembly photonic capsules with different optical responses depending on thermal history can be designed. Thermally responsive colloidal particles are formed by using hydrogel polymer with lower critical solution temperature (LCST), and these particles are encapsulated in capsules. Colloidal particles are gradually swollen as the temperature drops below LCST and effective volume fraction of the colloids in capsules increases, causing colloidal assembly. Herein, we control the crystallinity of colloids by modulating the rate of cooling. If the temperature decrease is slow enough, the colloid particles form a crystalline phase. If the cooling rate is too fast to prevent rearrangement, the colloids form glassy packing. Colloidal crystals have a high and narrow reflection peak while colloidal glasses have low and broad peak. Therefore, these capsules with unique optical responses can be a recorder of thermal history.