MENLO PARK, California — Scientists at SRI International have figured out how to make a plastic film that can stick to walls when you apply a small electric current — then peel off effortlessly when you turn the current off.

Why? They’re not entirely sure yet, but it’s pretty cool technology.

A recent SRI project aims to use the film to stick extension ladders to walls, so they don’t fall over when you’re climbing up them.

I saw a demonstration of the technology recently at SRI’s labs here, not far from Stanford University, which spawned the think tank in 1946 and spun it off as an independent nonprofit in 1970. The organization has been home to an impressive range of breakthroughs, from Douglas Engelbart’s pioneering work on mouse-driven graphical user interfaces to surgical robots, and has spawned a number of commercially successful spinoffs.

The key to on-demand stickiness is a special polymer film with a very low power (but high voltage) circuit printed on it. Applying 7,500 volts at 50-100 microamperes of current makes the polymer sticky enough to support small loads. Turn the current off, and the stickiness, called electroadhesion, dissipates within a few seconds.

Wrap that film around a couple of rollers, tank tread-style, and you’ve got a wall-climbing robot.

The robot shown in the video below has a footprint of about 1.5 by 2 feet, which gives it enough stickiness to lift itself (the robot weighs about 4 pounds) plus a 4-pound payload. It’s controlled by wireless signals from a game controller, though the controls are pretty limited: It can go forward (up) or backward (down). And it’s quite sticky, even on uneven surfaces like a painted cinder-block wall.

The SRI scientist who developed this technology in 2008, Harsha Prahlad, sees it as potentially useful for wall-climbing surveillance robots, or robots that can climb buildings, bridges, or other structures to inspect them for damage in places that humans can’t easily reach.

Other applications include pick-and-place systems in warehouses: A robot arm with an electroadhesive “pad” could use it to pick up objects, then set them on conveyor belts or in boxes.

It would also make a slick wall-hanging system for photo frames or even tablets like the iPad: Turn on the adhesive pad, stick it to the wall and walk away, with no wall-disfiguring nails or screws required. With a small solar panel, you can get enough energy from ambient light to power the electroadhesive film all day, Prahlad says.

See below for a video of the wall-climbing robot in action.

Note: The two “tails” sticking down from the bottom of the robot are there to keep the robot from peeling off the wall. By giving the robot an angular “brace” it increases the horizontal component of the force, which the electroadhesive film is better able to resist. Prahlad says that geckos’ tails function in a similar way: “If you cut off the tail from a gecko it can no longer climb.”