Paper TF-ThP15
Patterning of Nonwoven Fiber Mats by Atomic Layer Deposition

Thursday, October 31, 2013, 6:00 pm, Room Hall B

The ability to pattern substrates is an integral part of many industries, from integrated circuit manufacturing to newspaper printing. To apply features for flexible electronics, techniques such as screen printing, inkjet printing, or shadow masking are available. Alternatively, features can be created by a negative etch if the patterned areas can be sufficiently protected. However, these methods do not offer the ability to use patterning to produce conformally coated 3D structures on complex substrates. Nonwoven fiber mats are an example of a complex substrate, which offers highly tunable properties such as fiber chemistry, diameter and geometry, all of which can be produced in high volumes at very low cost.

In this work, we demonstrate a new method using Atomic Layer Deposition to selectively pattern features on nonwoven fiber mats, allowing for the creation of conformally coated 3D patterns. By compressing the sample between two patterning plates we are able to restrict precursor diffusion in the compressed region, but allow ALD to occur in the exposed portion of the sample, imparting the pattern on the substrate. By stacking multiple layers of substrate in the patterning plates, the 3D pattern that is created can easily be seen by deconstructing the layers or by cutting the sample to view a cross section of the feature. The impact of substrate chemistry (polypropylene, nylon, cotton) and structure (woven vs. nonwoven) as well as fiber diameter (microfibers vs. nanofibers) is examined. In addition the impact of deposition conditions (temperature, precursor exposure) and coating chemistry (Al₂O₃ and ZnO) is investigated. This technique will enable new applications for ALD coatings on flexible substrates; applications in gas and liquid sensors as well as flexible electronics will be discussed.