3D touchless multiorder reflection structural color sensing display

Abstract

The development of a lightweight, low-power, user-interactive three-dimensional (3D) touchless display in which a human stimulus can be detected and simultaneously visualized in noncontact mode is of great interest. Here, we present a user-interactive 3D touchless sensing display based on multiorder reflection structural colors (SCs) of a thin, solid-state block copolymer (BCP) photonic crystal (PC). Full-visible-range SCs are developed in a BCP PC consisting of alternating lamellae, one of which contains a chemically cross-linked, interpenetrated hydrogel network. The absorption of a nonvolatile ionic liquid into the domains of the interpenetrated network allows for further manipulation of SC by using multiple-order photonic reflections, giving rise to unprecedented visible SCs arising from reflective color mixing. Furthermore, by using a hygroscopic ionic liquid ink, a printable 3D touchless interactive display is created where 3D position of a human finger is efficiently visualized in different SCs as a function of finger-to-display distance.

Visualization of nonsingular defect enabling rapid control of structural color

“…Effective Young’s modulus of top layer ( E eff ) after swelling-deswelling cycles from rule of mixture was obtained of approximately 3 GPa by the relation of E eff = V PS E PS + V P2VP E P2VP . The estimated E QP2VP-gel was approximately 40 MPa, which is in good agreement with the value of a typical elastomer ( 23 ). We also calculated the maximum height of a swollen screw dislocation upon EtOH swelling based on the scheme in fig.…”

“…The TEM projection of the 20-nm-thick section sample strongly resembles that of a nonsingular spiral structure like that of a biphasic helicoid, which serves as a continuous pathway for the diffusion of the swelling agent from the top to the bottom of the film ( Fig. 2A ) ( 5 , 6 , 23 , 24 ).…”

“…A highly swollen BCP PC film was prepared as a dry solid using an IHN in the pristine PS- b -QP2VP BCP PC film ( 23 ). PEGDA ( M n = 700) (~50 wt % in water) was blended with Triton X-100 at a concentration of 1 wt %.…”

“…In most prior work, a swelling agent preferentially absorbed by one of the two BCP domains was used to ensure the mechanical stability of a BCP PC upon swelling ( 5 – 8 ). A variety of domain swelling agents have been demonstrated, including solvents, ionic liquids, sol-gel precursors, and photocrosslinkable hydrogels, giving rise to visible range SCs of BCP PCs, which are readily changed upon subsequent stimulation ( 6 – 8 , 15 , 23 ).…”

Respiratory Monitoring by Ultrafast Humidity Sensors with Nanomaterials: A Review

“…Here, reflected light of each interface in the stack interferes coherently under conditions satisfying Bragg’s law for the stack: mλ = 2( n h d h + n l d l )sinθ, where n h , d h , n l , and d l are the refractive indices and thicknesses of the high- and low-index layers, respectively. Reports of such Bragg stacks composed of organic/inorganic hybrid materials [ 93 , 94 ], inorganic materials [ 95 , 96 , 97 ], and organic materials [ 98 ] have demonstrated controllable and bright structural colors. Kou et al [ 93 ] recently reported the performance of a colorimetric Bragg stack humidity sensor responding to human breath, shown in Figure 11 .…”