Atomic layer deposition and abrupt wetting transitions on nonwoven polypropylene and woven cotton fabrics.
Atomic layer deposition (ALD) of aluminum oxide on nonwoven polypropylene and woven cotton fabric materials can be used to transform and control fiber surface wetting properties. Infrared analysis shows that ALD can produce a uniform coating throughout the nonwoven polypropylene fiber matrix, and the amount of coating can be controlled by the number of ALD cycles. Upon coating by ALD aluminum oxide, nonwetting hydrophobic polypropylene fibers transition to either a metastable hydrophobic or a fully wetting hydrophilic state, consistent with well-known Cassie-Baxter and Wenzel models of surface wetting of roughened surfaces. The observed nonwetting/wetting transition depends on ALD process variables such as the number of ALD coating cycles and deposition temperature. Cotton fabrics coated with ALD aluminum oxide at moderate temperatures were also observed to transition from a natural wetting state to a metastable hydrophobic state and back to wetting depending on the number of ALD cycles. The transitions on cotton appear to be less sensitive to deposition temperature. The results provide insight into the effect of ALD film growth mechanisms on hydrophobic and hydrophilic polymers and fibrous structures. The ability to adjust and control surface energy, surface reactivity, and wettability of polymer and natural fiber systems using atomic layer deposition may enable a wide range of new applications for functional fiber-based systems.
Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA.
G Kevin
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Hyde
Giovanna
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Scarel
Joseph C
JC
Spagnola
Qing
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Peng
Kyoungmi
K
Lee
Bo
B
Gong
Kim G
KG
Roberts
Kelly M
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Roth
Christopher A
CA
Hanson
Christina K
CK
Devine
S Michael
SM
Stewart
Daisuke
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Hojo
Jeong-Seok
JS
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Jesse S
JS
Jur
Gregory N
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Parsons
D000537:Aluminum Oxide / Q000737:chemistry; D032561:Cotton Fiber; D008422:Materials Testing; D010316:Particle Size; D011126:Polypropylenes / Q000737:chemistry*; D013499:Surface Properties; D017155:Wettability
D011126:Polypropylenes; D000537:Aluminum Oxide