A hand on the shoulder, a stroke on the arm, a hug: such touches can calm, comfort and generally convey a sense of safety, security and closeness. When the nerve cells in the skin transmit such stimuli, many areas of the brain become active in a flash and stimulate the body's own biochemistry. Hormones and other messenger substances are released, including oxytocin, which creates a sense of well-being and bonding. Video conferencing, on the other hand, tends to leave us cold; we hardly feel any sense of security or closeness - there is a lack of physical contact. But what happens when closeness is important, when children are seriously ill but their parents can't see them? When physical contact is not allowed due to a weakened immune system?

A research team at Saarland University, Saarland University of Applied Sciences (htw saar), the Center for Mechatronics and Automation Technology (ZeMA) and the German Research Center for Artificial Intelligence (DFKI) are working together across disciplines to ensure that children in isolation wards can feel the physical closeness of their parents even during virtual visits and can immerse themselves in this experience as realistically as possible. At the interface of engineering science, neurotechnology, medicine and computer science, the researchers are developing a virtual encounter in the "Multi-Immerse" project that is designed to appeal to all the senses. "Immerse" stands for "immersion", for intensive sensory perception. Using new technologies, young patients should be able to see, hear and feel their parents and siblings as realistically as possible and still feel their close proximity despite the physical separation.

The research group led by Professors Stefan Seelecke and Paul Motzki at Saarland University and the ZeMA in Saarbrücken is responsible for feeling and tactile perception: they are specialists in giving surfaces new abilities with the help of lightweight silicone films. The engineers are turning the films, which are just 50 micrometers thick, into a second skin: just as the skin is the human body's interface to the real outside world, the film is to become its interface to the virtual world. The aim is to create a new perception of the body in fictional reality.

Incorporated into a textile, the films are intended to transfer the touches to the child's skin that occur when the mother or father strokes a second smart textile elsewhere. "We use the films, known as dielectric elastomers, as sensors to detect the touch movements and also as actuators, i.e. drives, to transmit these movements," explains Stefan Seelecke, Professor of Intelligent Material Systems. As a sensor, the film recognizes how precisely the hand and fingers press, dent and stretch the film when it is stroked. This exact deformation caused by the touching movements is imitated by the film in a second textile on the child's skin in order to give the impression of being stroked on the arm, for example.

"The top and bottom of the film are printed with a conductive, highly stretchable electrode layer. When we apply an electrical voltage to this, the electrodes attract each other due to the electrostatic attraction and compress the film, which moves to the side, thereby increasing its surface area," explains Professor Paul Motzki, who holds the bridging professorship "Smart Material Systems for Innovative Production" between Saarland University and ZeMA. The electrical capacitance of the film changes with every slightest movement: a physical quantity that can be measured. When a finger strokes the film, it deforms it and each individual position can be assigned an exact measured value of the electrical capacitance: A certain number describes a very specific position of the film. A sequence of these individual measured values sets a sequence of movements in motion. The film is thus its own stretchable sensor and recognizes how it is deformed.

At HANNOVER MESSE 2024, the team will be demonstrating its technology with a kind of clock with a smart film attached to the back. "We can string together several of these smart components so that, for example, a long stroking movement can be transmitted. To do this, we network these components so that they communicate and cooperate with each other like a swarm," explains Paul Motzki.

The process is inexpensive, lightweight, noiseless and energy-efficient. The film technology can also make the gaming experience in computer games more intense through realistic body perception. In other projects, the engineers use their films to line work gloves for Industry 4.0 or create the impression of button edges so that buttons or sliders can be felt out of nowhere, making user interfaces more user-friendly.

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