Gecko-Like Dry Adhesive Surfaces and Their Applications: A Review

Gecko has the ability to climb flexibly on various natural surfaces because of its fine layered adhesion system of foot, which has motivated researchers to carry out a lot of researches on it. Significant progresses have been made in the gecko-like dry adhesive surfaces in the past 2 decades, such as the mechanical measurement of adhesive characteristics, the theoretical modeling of adhesive mechanism and the production of synthetic dry adhesive surfaces. Relevant application researches have been carried out as well. This paper focuses on the investigations made in recent years on the gecko-like dry adhesive surfaces, so as to lay the foundation for further research breakthroughs. First, the adhesion system of gecko’s foot and its excellent adhesive characteristics are reviewed, and the adhesive models describing the gecko adhesion are summarily reviewed according to the different contact modes. Then, some gecko-like dry adhesive surfaces with outstanding adhesive characteristics are presented. Next, some application researches based on the gecko-like dry adhesive surfaces are introduced. Finally, the full text is summarized and the problems to be solved on the gecko-like dry adhesive surfaces are prospected.

Wear Properties of Nanoclay Modified Basalt Fibre Composites Under Dry Adhesive Sliding, Two-body Abrasive and Slurry Pot Erosive

This paper reports the effect of 1.0 wt%, 3.0 wt% and 5.0 wt% nanoclay loadings on specific wear rate properties of basalt fibre reinforced polymer (BFRP) composites. The specific wear rate properties of the BFRP composites were analysed at three different wear conditions, i.e. dry adhesive sliding, two-body abrasion and slurry pot erosion in which the composites slide against smooth steel, rough silicon carbide and medium coarse sand mixture, respectively. The operating parameters for the wear tests were set at 30 N load, 300 rpm speed and 10 km distance. The results demonstrated that nanoclay incorporation enhanced the adhesive and erosive wear properties of BFRP composites up to 32% and 51%, respectively. In contrast, nanoclay incorporation deteriorated the abrasive wear properties of BFRP with increasing in nanoclay loading. The morphology of worn surfaces was evaluated using scanning electron microscopy (SEM) to study the wear behavior of the nanoclay modified BFRP composites. It concluded that nanoclay incorporation exhibited significant influence on wear properties of the polymer composites depending on the wear environment condition.

The effect of channel aspect ratio on air entrapment during imbibition in soil-on-a-chip micromodels with 2D and 2.5D pore structures

“Soil-on-a-chip” micromodels designed with X-ray CT images were fabricated by tabletop CNC machining and dry adhesive bonding. The competition between film flow and piston displacement causes the air entrapment differences in 2D and 2.5D micromodels.