This study proposes a novel skinny button with multimodal audio and haptic feedback to enhance the touch user interface of electronic devices. The active material in the film-type actuator is relaxor ferroelectric polymer (RFP) poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) [P(VDF-TrFE-CFE)] blended with poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)], which produces mechanical vibrations via the fretting vibration phenomenon. Normal pressure applied by a human fingertip on the film-type skinny button mechanically activates the locally concentrated electric field under the contact area, thereby producing a large electrostrictive strain in the blended RFP film. Multimodal audio and haptic feedback is obtained by simultaneously applying various electric signals to the pairs of ribbon-shaped top and bottom electrodes. The fretting vibration provides tactile feedback at frequencies of 50–300 Hz and audible sounds at higher frequencies of 500 Hz to 1 kHz through a simple on-off mechanism. The advantage of the proposed audio-tactile skinny button is that it restores the “click” sensation to the popular virtual touch buttons employed in contemporary electronic devices.

With the rise of portable and wearable electronics, a fast‐charging, long‐lasting power solution is needed; thus, there are attempts to harvest energy from the ambient environment. Mechanical energy harvesting through piezoelectric and triboelectric nanogenerators (PENG and TENG) is a promising approach due to their light weight, low cost, and high‐power density in comparison to other technologies. Both types of generators are capable of charging portable and smart devices on their own by converting mechanical energy into electricity. However, most previous methods have excessive input conditions, such as high rpm and input frequency, that can be only applied with other actuators. Here, a hand‐held gyroscopic generator is presented that uses the gyroscopic principle to reach a rotation rate above 8000 rpm with only hand input. The generator comprises a rotating flywheel inside a casing. Both the flywheel and casing have a TENG, and with a hybrid generator, electrical power is produced from rotation, vibration, and centrifugal force during operation. The device shows a consistent open‐circuit voltage (V OC) of 90 V and a closed‐circuit current (I CC) of 11 µA with a frequency of 200 Hz. As a stand‐alone device, this generator can power portable sensors and smartphones through hand rotation.

Tactile perception in large-area displays is currently attracting substantial research attention since, in conjunction with visible and auditory sensations, it provides more immersive and realistic interactions with displayed contents. Here, a new vibrotactile display based on the fretting phenomenon is developed for the first time to provide localized tactile feedback on a large-area display. Normal pressure by a human fingertip activates a locally concentrated electric field in a relaxor ferroelectric polymer (RFP) film under the contact area, which produces a localized electrostrictive strain. The synergistic interplay among the localized electric field, electrostrictive deformation of the RFP film, and contact area dramatically amplifies acoustic vibrations near the contact edge of a human fingertip. A blend of poly(vinylidene fluoride−trifluoroethylene−chlorofluoroethylene) terpolymer and poly(vinylidene fluoride−trifluoroethylene) (55:45) copolymer is proposed for the RFP to provide an enhanced actuation performance even at elevated temperatures. The fretting-vibrotactile mechanism has several interesting properties, such as tactile feedback on a stationary fingertip, pressure-responsive simple on−off mechanism, multitouch interaction, excellent transparency, and easy integration with capacitive or resistive touch sensors and friction-based haptic-feedback mechanisms. An array of RFP film vibrators can provide addressable content-related multiple tactile feedback on large-area displays by modulating the frequency, amplitude, and profile of the driving voltage signals.

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