Dissolvable Nanofabrication Method Inspired by Cicada Wings

Innovation: Academia

University of Illinois Urbana-Champaign

2020

Image: Katja Schulz / Wikimedia Commons / CC BY - Creative Commons Attribution alone

Modify Material Characteristics

The materials found in living systems are variable, yet often made from the same basic building blocks. For example, all insect exoskeletons consist of a material called chitin. Because material resources are limited, each material within or used by a given living system must frequently serve multiple purposes. Therefore, living systems have strategies to modify materials’ softness, flexibility, and other characteristics. To ensure survival, the benefits of these modifications must outweigh the living system’s energy and material expenditure to generate them. For example, spiders store the liquid components of spider silk in a gland, converting them into silk thread when needed. Some threads have different characteristics, such as elasticity and UV reflectance, than others.

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Modify Size/Shape/Mass/Volume

Many living systems alter their physical properties, such as size, shape, mass, or volume. These modifications occur in response to the living system’s needs and/or changing environmental conditions. For example, they may do this to move more efficiently, escape predators, recover from damage, or for many other reasons. These modifications require appropriate response rates and levels. Modifying any of these properties requires materials to enable such changes, cues to make the changes, and mechanisms to control them. An example is the porcupine fish, which protects itself from predators by taking sips of water or air to inflate its body and to erect spines embedded in its skin.

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Protect From Excess Liquids

While water is essential to life, too much water or other liquids can overwhelm living systems. Excess liquids can, for example, decrease a living system’s access to oxygen, promote excessive bacterial or fungal growth, or strip away soil and nutrients. To prevent the accumulation of excess liquids, living systems must control the movement of liquids across their boundaries or surfaces. They do so using waterproofing materials or structures, slowing flow, and/or facilitating flow to move the liquid away. Plant leaves, for example, commonly have waxy surfaces comprised of water-repelling chemicals to keep water from engorging the leaves or facilitating bacterial and fungal growth.

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Nanofabrication method from University of Illinois Urbana-Champaign uses a dissolvable template to create nanostructures without causing damage.

Benefits

Scalable
Inexpensive
Replicable

Applications

Contact lenses
Textiles
Medical devices
Solar Energy

UN Sustainable Development Goals Addressed

Goal 9: Industry Innovation & Infrastructure
Goal 12: Responsible Production & Consumption

Bioutilization

Biological material

The Challenge

Large volume manufacturing is susceptible to small variations in the product. In order to function properly, nanostructures need to be accurately made at a large scale. Current techniques are unable to make these intricate structures, leading to slower production and high costs. Nanoimprinting lithography is an effective method for imprinting fine structures, but it can be labor-intensive and expensive. Some techniques use toxic materials or high temperatures that are not compatible with biological samples such as plants or insects.

Innovation Details

The nanofabrication method uses nanoimprinting lithography, which is a process capable of replicating nanostructures as small as 100 nm. It uses a piece of biological material, for example a cicada wing, as a template. Nail polish is then applied to wing, which is allowed to dry at room temperature. Once dry, the template can be coated with a or metal and then dissolved away, leaving only the replica metal or polymer. This allows for the replication of fine nanostructures using only simple materials, at a larger scale than previous technologies.

Biological Model

The wings of cicadas shed dirt and water via nanoscale protrusions, measuring only 300 nanometers. The protrusions keep water off the wing and the air pockets that surround the protrusions buoy the droplets.

References

Journal article

Dissolvable Template Nanoimprint Lithography: A Facile and Versatile Nanoscale Replication Technique

Nano Letters

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