Abstract
A tunable optical lens can tune or reconfigure the lens material itself such that it can eliminate the moving part of the lens, which brings broad technological impacts. Many tunable optical lenses have been implemented using electroactive polymers that can change the shape of the lens. However, the refractive index (RI) change of electroactive polymers has not been well investigated. This paper investigated the RI change of CNC-based transparent and electroactive polyurethane (CPPU) in the presence of an actuating electric field. The prepared CPPU was electrically poled to enhance its electro-optical performance, and the poling conditions in terms of frequency and electric field were optimized. The poled CPPU was characterized using a Fourier transform infrared spectroscopy and a refractometer. To investigate the RI change in the presence of an actuating electric field, the poled CPPU was constrained between two electrodes with a fixed distance. The RI linearly increased as the actuating electric field increased. The RI change mechanism and the optimized poling conditions are illustrated. The tunable RI is a promising property for implementing a tunable optical lens.
Highlights
A tunable optical lens can change the focal distance and refractive index, optical angle, and optical intensity by tuning or reconfiguring the lens material itself (Choi et al, 2017; Ghilardi et al, 2019)
The result might be due to wealthy OH groups in cellulose nanocrystal (CNC) act as hydrogen bonding sites to N-H groups, which are infiltrated between ordered urethane chains and played as an impurity for polyurethane crystal
The Fourier transform infrared spectroscopy (FTIR) results showed that CNC was well interacted with the amine group of polyurethane by hydrogen bonding, and urethane bonding was well-formed
Summary
A tunable optical lens can change the focal distance and refractive index, optical angle, and optical intensity by tuning or reconfiguring the lens material itself (Choi et al, 2017; Ghilardi et al, 2019). There are two distinct ideas to implement a tunable optical lens by changing the shape of the lens and tuning the refractive index (RI) of the lens material. There are many available EAPs for tunable optical lens applications such as thermo-responsive polymers (Kim J. et al, 2019), hydrogels (Jayaramudu et al, 2016, 2017), and dielectric elastomer (DE). In realizing the tunable optical lens, Refractive Index Change of CPPU lens material’s actuation performance against repetitive deformation and miniaturization should be carefully considered. Another consideration is the lens material should maintain its transparency from repeated light exposure and actuation. The choice of dielectric fillers for DE in tunable optical lens research is limited because they should be transparent
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
