H. Daghigh Shirazi: Fabrication of bio-inspired films and surfaces

Content of the thesis: 

Plants exemplify nature’s ability to address challenges through efficient principles, such as water repellency and light management. This dissertation explores fabrication routes to harness such principles and fabricate multifunctional films and surfaces. To achieve this, three fabrication strategies are pursued: (1) preparing surface structures by using leaves as templates, (2) independently introducing micro- and nano-scale surface structures, and (3) spinning cellulose nanofibril (CNF) films.

The first approach focuses on replicating the surface structure of leek leaves to fabricate translucent superhydrophobic films. When integrated onto perovskite solar cells, these structures enhance efficiency and facilitate dust removal by enabling self-cleaning. The second approach combines optical patterning of azopolymers with thermal shrinkage of a mechanically mismatched bilayer to create hierarchical surface structures at two distinct length scales. As a result, this method allows the design of multiscale surface structures without relying on templates. The third approach introduces a CNF film-spinning method to achieve anisotropic humidity responsiveness and indicating a potential pathway toward continuous CNF film fabrication.

The insights from the developed routes highlight the potential of bio-inspiration in the fabrication of multifunctional materials. The results further demonstrate the simplicity yet effectiveness of the developed methods, lowering the barrier to practical application. As a result, these findings point to broader opportunities for incorporating bio-inspired design into emerging technologies.

Keywords: multifunctional materials, surface patterning, soft lithography, light management, cellulose, superhydrophobicity

Opponent: Prof. Emily Cranston, The University of British Columbia, Canada

Supervisor: Prof. Jaana Vapaavuori, Aalto University School of Chemical Engineering

Link to electronic thesis: LINK

Link to the remote defense: LINK