Taming Macromolecules by Light – Supramolecular Photoresponsive Materials at Three Different Length Scales

Assistant Professor Jaana Vapaavuori, Department of Chemistry and Materials Science, Aalto University, will be talking on the subject of:

Taming Macromolecules by Light – Supramolecular Photoresponsive Materials at Three Different Length Scales

as part of the Chemistry and Materials Science Seminar Series.

Abstract:

When noncovalently bound to macromolecules, photoisomerizing molecules can be harnessed for controlling the properties of materials at length scales spanning at least three orders of magnitude. In this presentation, I will discuss my recent work seeking fundamental understanding of how the nanometer-scale photoinduced changes in azobenzene and spiropyran derivatives can be translated into different applications involving polymers. First, starting from the length scale of 10-100 nm, the morphology of self-assembled diblock copolymers can be switched by supramolecularly attaching azobenzene molecules selectively to one of the blocks upon dip-coating nanostructured thin films. Similarly, the size of diblock copolymer micelles, consisting of a neutral and polyzwitterionic blocks, can be doubled upon photoisomerizing spiropyran guest into its merocyanine form. Second, I will discuss the supramolecular material design guidelines of how azobenzene motion is converted into all optical surface patterning resulting in micron-scale surface reliefs. Third, stimuli-induced changes visible at the macroscopic scales are discussed, by introducing supramolecular polymer-azobenzene humidity memories and light-switchable polymer wrinkles at the scale of approximately 10-100 μm. This presentation highlights that the key to achieving high-tech applications is to first understand the delicate balance of supramolecular interactions in soft condensed materials, and then develop methods for controlling them.

Brief bio:

Dr. Jaana Vapaavuori defended her doctoral thesis, “The Supramolecular Design of Efficient Photoresponsive Materials”, done under supervision of Dr. Arri Priimagi and Prof. Matti Kaivola, in the department of Applied Physics at Aalto University, Helsinki, Finland, in 2013. After having completed two prestigious postdoctoral fellowships (Postdoctoral Fellow of Academy of Finland and Banting Postdoctoral Fellow) at Tampere University of Technology and at University of Montreal, respectively, she started as an assistant professor at the Department of Chemistry at University of Montreal in 2018. She moved her research group to the Department of Chemistry and Materials Science at Aalto University in March 2019. Her current research interests involve developing new materials and supramolecular design concepts for stimuli-controllable nanostructures, all-optical surface patterning of polymers, and electrochemical devices.

The seminar is hosted by Dr. Pekka Peljo.