Preparation and application of thermochromic and thermoregulation bi-functional microcapsules

Aiming at the current problems of low enthalpy value and low coverage rate of phase change solvent in thermochromic microcapsules， the bi-functional microcapsules with reversible thermochromic property， and heat storage and temperature regulation properties were prepared by in-situ polymerization using chromogenic agent 2′-chloro-6′-（diethylamino） fluorane， chromogenic agent bisphenol A， and phase change material hexadecanoic acid dodecanol ester as the composite core materials and melamine resin as the wall material. The surface morphology， thermal properties， and discoloration properties of the microcapsules were studied. The results show that when the mass ratio of 2′-chloro-6′-（diethylamino） fluorane， bisphenol A， and hexadecanoic acid dodecanol ester is 0.3∶4∶60 and the mass ratio of core to wall materials is 0.8∶1， the prepared microcapsules have smooth and spherical shape，the average particle size is about 3 μm，the encapsulation rate reaches 86.4%， the latent heat value is 138.3 J/g， showing good color recovery after 120 cycles of temperature rising and cooling. After this microcapsules are applied on cotton fabrics by screen printing， the latent heat value of the printed fabric can reach 9.74 J/g， and the fast reversible color change from red to white in the range of 25-40 ℃ can be achieved，exhibiting good heat storage temperature regulating property and thermal color changing response property.