||The active scattering smart windows bring great convenience for life. By introducing flexibility, they will be more convenient to be used. Due to Roll-to-Roll production process, the fabrication of flexible substrate based devices is time-consuming and cheaper than the one of glass based devices. Additionally, free-cutting can be achieved by flexible substrates which can meet requirements for any sizes and shapes. Accordingly, active scattering smart windows are expected to be able to be common in our life. |
The main aim of this study is to develop a flexible smart window by virtue of a current bi-stable smart window cooperating with an encapsulation of polymer. At first, we developed a new method to control an encapsulation of polymer based on traditional thermal induced phase separation (TIPS). By virtue of the new method, structures of polymer could be manipulated by parameters including temperature, duration of phase separation, and concentration of polymers. Furthermore, the difference of encapsulated structures of polymers before and after the saturated precipitation of liquid crystal and the reasons were uncovered. Further, with different structures of encapsulated polymer, a dynamic scattering mode (DSM) was employed to exhibit the scattering state, and the influence of different structures of encapsulated polymer on the optical performance was investigated. We found that the amount of polymer walls and liquid crystals near polymer walls had a considerable influence on the optical performance. Moreover, if the concentration of polymer was too low, polymer walls would be broken in the process of TIPS. Free cutting of substrates became invalid due to the loss of closed encapsulation structures accordingly. Combining TIPS and photo-induced phase separation (PIPS), finally, we succeeded in fabricating closed encapsulation structure with polymers of low concentration.
Further, to investigate the vertical structures and the surface anchoring force of encapsulated polymers, we observed the arrangement of nematic liquid crystal (NLC) in encapsulated structures which was produced by TIPS. Finally, after the optimization of encapsulated structures and the optical performance in a glass cell, flexible substrates were introduced to fabricate a flexible smart window. Finally, we successfully maintain the optical performance in a flexible cell, and the flexibility was fully tested.