Self-made straw launched
Australian scientists have made a new material that, on contact with water, folds itself into a straw and starts sucking up liquid.
The bizarre new material – developed at ANU - could be used as a cheap and easy fluid distribution system for medical sample analysis, biological sensors or micro-robotics.
The material appears paper-like in its resting form, but when just a drop of water is applied, it responds by folding into a tube and forcing the water along the inside.
It unfurls on contact with ethanol.
The material is made of two thin nano-fibre layers sandwiched together.
The top functional layer, made of polycaprolactone nanofibres, is the water-responsive and energy-dense (superhydrophilic), allowing it to draw the material up around the water droplet.
The bottom layer is made of polyvinylchloride (PVC) micro-fibres which is strongly water repellent (superhydrophobic). This prevents the water from escaping once the material has rolled into a tube.
Researchers at ANU’s Nanotechnology Research Laboratory of the Research School of Engineering found that the channelled water could even navigate challenging shapes such as T-intersections, forks and curves.
The ability to control and direct the flow of tiny amounts of liquid will be useful where there are inherent dangers to humans, such as highly reactive environments or with bio sensors of infectious diseases.
The material is cheap and its designers say the manufacturing process is non-toxic and will scale well to industrial levels.