Providing the Warfighter with increased protection and awareness in the field can often come at the expense of comfort and mission effectiveness. Extra protection in the form of specialty uniforms and materiel add to the physical burden of the Soldier. A uniform comprised of a single multifunctional layer could address this problem because it could perform multiple functions without increasing the physical burden. Two critical functions to add to a Soldier’s uniform would be water repellency and decontamination. Certain enzymes have been shown to be effective and selective chemical decontamination agents (here we will use a model enzyme to simulate decontamination activity). A multifunctional coating that is predominantly hydrophobic would repel water, keeping the wearer dry and comfortable, and provide passive protection by allowing aqueous liquids to roll-off. However, enzymes often require aqueous environments for proper activity. This situation presents an opportunity to determine the surface composition needed to achieve the highest enzyme activity without degrading the water repellent properties. In nature, the skin of the Stenocara desert beetle effectively balances orthogonal hydrophobic and hydrophilic surface properties. No catalytic activity occurs on the beetle’s skin, but it does provide an example of a multifunctional system in nature balancing orthogonal functions.<br/><br/>In order to create a multifunctional surface that supports both enzyme activity and water repellency, we have taken a cue from the Stenocara beetle skin and fabricated an amphiphilic surface by using a binary self-assembled monolayer system. In collaboration with Boston University, we have used photolithography to pattern micron-sized hydrophilic domains amongst a hydrophobic background. Once patterned, we can covalently attach enzymes to the hydrophilic regions while the hydrophobic background provides the water repellency function. Using photolithography we can control the size and spacing of the hydrophilic domains to determine the effects this has on balancing these two functions. We will also show how using an engineered enzyme allows for site-selective immobilization which improves the overall efficiency of the enzyme activity. In this study I use contact angle goniometry, fluorescence enzyme assays and surface characterization techniques such as atomic force microscopy and infrared spectroscopy to find the surface composition that maximizes both functions simultaneously.

Balancing multiple orthogonal functions simultaneously on a single surface

255th National Meeting (2018)

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