Preface

The field of biological and bio-inspired adhesive systems underwent enormous developments during the past 15–20 years. Starting from curiosity-driven science with questions like “Why does the gecko or the fly not fall from the wall?”, it developed into one of the most exciting interdisciplinary fields of research, where biologists, chemists, materials scientists, even theoretical physicists, and engineers meet together to unravel natures’ mystery of temporary, strong, and reliable adhesion. Although enormous efforts, to understand attachment principles of biological prototypes, such as geckos, spiders, flies, and beetles were recently undertaken, until now, only very few biomimetic materials, inspired by the feet of these animals, are commercialized. What could be the reasons for the shortage of such bio-inspired products? One potential reason could be that we are still limited in industrial processes capable of mass production of structures with such extreme complexity and small feature size. Another reason could be that we still have not properly understood functioning of biological prototypes. The latter reason might be due to the fact that we lack information about the way how the animals use their attachment systems in real environment. Also biologically inspired artificial attachment devices are usually tested on smooth flat substrates under laboratory conditions. This approach is perfectly fine as a first step of the biomimetic technical development, but not lead to the development of real-world applications. Additionally, if we want to fix things quasi-permanently on the wall, we should not necessarily consider gecko-inspired materials. Geckos and Co are fast-running animals with an attachment system optimized for short-term and highly dynamic adhesion. Therefore, these attachment systems mainly rely on elaborate nanoscopic thin film-like spatula-shaped contact elements. Instead, we should search for other specialized biological prototypes, for example, organisms, which utilize long-term adhesion. Their strong and, most important, passive attachment systems mainly rely