Project 10
Bio-inspired Surfaces: Fabrication of Rose Pedals Using Glancing Angle Deposition (GLAD)
(Dr. Chuang Qu, KY Multiscale)
Natural micro/nano structures often serve as remarkable sources of inspiration for engineering innovations. For instance, examples such as cicada wings [1], lotus leaves [2], moth eyes [3], and rose petals [4] have led to significant advancements. Rose petals surfaces offer extraordinary wetting abilities called “parahydrophophobic”, meaning the surfaces are non-wetting yet adhesive. As shown in Fig.1, the rose petal surfaces are composed of hierarchical micro and nano structures, and this unique morphology caused the parahydrophobic property of the surfaces. In this research, the focus is on the recreation of synthetic rose petals.
Picture 1. Picture and SEM images of Rose Petals.
The challenge for recreating patterns from nature is the ability to create nanostructures, especially on curved surfaces, scalability of the surfaces, and cost-effectiveness of the processes. One technique that is suitable for generating nanostructures is glancing angle deposition (GLAD) [5], as shown in Fig. 2. It is a physical vapor deposition process, and the nanostructures can be generated from a single deposition. The mechanism of this technique is based on ballistic shadows from pre-determined or early-deposited nucleation sites, and the shadowing effect creates deposition-free area on the substrate for the separated nanofeatures. Hierarchical micro/nano structures have been demonstrated by GLAD with proper seeding schemes, such as line seeds [6] (Fig 2d) and sphere seeds [7] (Fig 2e). The strategy of combining GLAD with sphere seeds is a proper way of recreating the structures on rose pedals.
Picture 2. (a) Demonstration of the GLAD process, (b) natural seeds and subsequent tapered nanocolumn growth and extension during the GLAD process, (c) closeup of the tapered nanocolumns using natural seeds, (d) thin nanofins fabricated using GLAD and patterned line seeds, and (e) nanocolumns fabricated using GLAD with nanodispersed spheres (patterned nanosphere seeds).
In this project, the REU student will have the following tasks: 1) capturing and analyzing scanning electron microscope images of rose petal surfaces; 2) Design a fabrication process that incorporates both micro- and nanofabrication techniques for the creation of hierarchical structure; 3) accessing the class-100 cleanroom to synthesize the samples 4) characterizing the samples using SEM and a goniometer 5) exploring possibilities for scaling the process.
References
[1] Qu, C. et al. Bio-inspired antimicrobial surfaces fabricated by glancing angle deposition. Sci. Rep. 13, 207 (2023).
[2] Jiang, R. et al. Lotus-leaf-inspired hierarchical structured surface with non-fouling and mechanical bactericidal performances. Chem. Eng. J. 398, 125609 (2020).
[3] Ji, S., Park, J. & Lim, H. Improved antireflection properties of moth eye mimicking nanopillars on transparent glass: Flat antireflection and color tuning. Nanoscale 4, 4603–4610 (2012).
[4] Chakraborty, M., Weibel, J. A., Schaber, J. A. & Garimella, S. V. The Wetting State of Water on a Rose Petal. Adv Mater Interfaces 6, 1–7 (2019).
[5] Taschuk, M. T., Hawkeye, M. M. & Brett, M. J. Glancing Angle Deposition. Handbook of Deposition Technologies for Films and Coatings (Elsevier Ltd., 2010). doi:10.1016/B978-0-8155-2031-3.00013-2.
[6] Qu, C., Alphenaar, B., McNamara, S. & Walsh, K. Design of line seeds for glancing angle deposition. J. Vac. Sci. Technol. A 39, 043404 (2021).
[7] Qu, C., McNamara, S. & Walsh, K. Design of sphere seeds for glancing angle deposition. J. Vac. Sci. Technol. A 40, 033413 (2022).
