Observation of nanoscale behavior of light driven polymers using combination microscopy technology

Expanding our scientific understanding often boils down to observing what is happening as closely as possible. Now, researchers from Japan have observed the nanoscale behavior of azo polymer films and triggered them with lasers.

In a study published in Nano Express last month, researchers at Osaka University used a combination of cutting-edge scanning high-speed atomic force microscopy and optical microscopy to create films as polymer films changed.

Azo polymers are photoactive materials, which means they undergo changes when light shines on them. Specifically, light can alter their chemical structure, thereby altering the surface of thin films. This makes them very interested in applications such as optical data storage and providing light triggered motion.

The ability to use focused laser to initiate these changes during image capture is called in situ measurement.
"Usually, changes in polymer films are studied by processing them, such as by irradiating them with light and then measuring or observing them. However, the information provided is limited," explained Keishi Yang, the main author of the study. "The use of HS-AFM devices, including inverted optical microscopes with lasers, allows us to trigger changes in azo polymer films while observing them in real-time with high spatiotemporal resolution."

HS-AFM measurement can track the dynamic changes on the surface of polymer films in movies at a speed of two frames per second. It was also found that the direction of polarized light used has an impact on the final surface pattern.

Further research using in-situ methods is expected to thoroughly understand the mechanism of photo driven azo polymer deformation, thereby maximizing the potential of these materials.

"We have demonstrated our technique for observing polymer membrane deformation," said Takayuki Umakoshi, senior author of the study. However, in doing so, we have demonstrated the potential to combine cutting-edge scanning HS-AFM with laser sources for materials science and physical chemistry.

Materials and processes that respond to light are important in a wide range of fields in chemistry and biology, including sensing, imaging, and nanomedicine. In situ technology provides an opportunity to deepen understanding and maximize potential, and therefore has the potential to be applied to various optical devices.

Source: Laser Net