Attachment through the interlocking of surface features is found throughout nature, including in dragonflies, wasps, and goosegrass. Biological attachment systems have inspired commercial fasteners such as Velcro, which mimics the hooked spines of burdock seeds.

These “probabilistic” fasteners work because they are designed with complementary attachment features on their two surfaces which interlock. For instance, Velcro and 3M dual lock are hook and loop fasteners.

The essential problem with designing fasteners is that the interlocking features are rigid. This requires hard, stiff materials, which can cause damage to delicate surfaces (such as fabrics) when pulled apart, as well as producing an unpleasant ripping noise. Shapes other than hooks and loops have been explored, with researchers concluding that overhanging features are necessary for attachment strength.

Now, researchers at Wageningen University in the Netherlands have presented an alternative design for a fastener which can be made from softer and more flexible materials while providing sufficient interlocking force to hold strong. The proposed design has a tiny half-spherical “mushroom” design.

The researchers created this shape through moulding and 3D printing. This material was safely attached to three different fabrics with regular and irregular mesh sizes, and removed without causing damage.

“We wanted to prove that, if you go towards these less stiff features, they can be used to attach and detach to soft and delicate surfaces like fabrics, without damage,” said Dr Preeti Sharma, who led the Biointerphases study. “There is still a lot of research to be done, but the mushroom-shaped design worked quite well for soft mechanical fasteners.”

The design could lead to a more pleasant fastener for consumers as well as advances in the field of soft robotics. In this field – which involves building robots with designs mimicking soft-bodied creatures such as octopuses, rays, and worms – interfaces play an important role. For instance, the mushroom fastener design could be applied to help robots adhere to walls and ceilings like a gecko.

Sharma said that further research into the design is necessary before it is ready to be used in a commercially available product, such as experimenting with lengthening or shortening the mushroom shape to make it more effective.

Attachment through the interlocking of surface features is found throughout nature, including in dragonflies, wasps, and goosegrass. Biological attachment systems have inspired commercial fasteners such as Velcro, which mimics the hooked spines of burdock seeds.

These “probabilistic” fasteners work because they are designed with complementary attachment features on their two surfaces which interlock. For instance, Velcro and 3M dual lock are hook and loop fasteners.

The essential problem with designing fasteners is that the interlocking features are rigid. This requires hard, stiff materials, which can cause damage to delicate surfaces (such as fabrics) when pulled apart, as well as producing an unpleasant ripping noise. Shapes other than hooks and loops have been explored, with researchers concluding that overhanging features are necessary for attachment strength.

Now, researchers at Wageningen University in the Netherlands have presented an alternative design for a fastener which can be made from softer and more flexible materials while providing sufficient interlocking force to hold strong. The proposed design has a tiny half-spherical “mushroom” design.

The researchers created this shape through moulding and 3D printing. This material was safely attached to three different fabrics with regular and irregular mesh sizes, and removed without causing damage.

“We wanted to prove that, if you go towards these less stiff features, they can be used to attach and detach to soft and delicate surfaces like fabrics, without damage,” said Dr Preeti Sharma, who led the Biointerphases study. “There is still a lot of research to be done, but the mushroom-shaped design worked quite well for soft mechanical fasteners.”

The design could lead to a more pleasant fastener for consumers as well as advances in the field of soft robotics. In this field – which involves building robots with designs mimicking soft-bodied creatures such as octopuses, rays, and worms – interfaces play an important role. For instance, the mushroom fastener design could be applied to help robots adhere to walls and ceilings like a gecko.

Sharma said that further research into the design is necessary before it is ready to be used in a commercially available product, such as experimenting with lengthening or shortening the mushroom shape to make it more effective.