Tunable Artificial Iris Controlled By Photo/Thermal Exposure Based On Liquid Crystalline Elastomers

The iris, part of the eye structure, is an important tissue in organisms. Here, a tunable artificial iris showing widening and closing of the pupil in response to near-infrared (NIR) light is demonstrated. Liquid crystalline elastomers (LCEs) are synthesized via Michael addition and photopolymerization. To prepare an artificial iris, a predesigned stainless steel mold with a specific structure is created for the preparation of a single shaped LCE piece. Through the assembly of individual shaped LCE pieces, an artificial iris is fabricated. To enhance the photosensitivity, polydopamine (PDA) is coated on the surface of the fabricated iris. The PDA-coated artificial iris shows reversible pupil widening and closing via exposure to NIR light. The dependence of pupil size on NIR intensity shows a function similar to the human iris. As far as it is known, the fabricated artificial iris with 2D radial motion is the first example prepared from a liquid crystalline elastomer showing a tunable aperture size controlled by the surrounding light intensity. The synthesized artificial iris is expected to show potential for multiple applications in biomimicry and biomedical science.