1300877238-UK_SOW.docx

STATEMENT OF WORK – 11/01/2019

Proposed Title: ‘Retention and Repellency in Coating Technologies’ PROPOSED START DATE Sept 15, 2020

4555 Overlook Ave., S. W.

College of Engineering

Washington, DC 20375

351 Ralph G. Anderson Building

PI: Brandy White, PhD

Lexington, KY 40506 Site PI: Jonathan Pham

(859) 257-3866 Jonathan.pham@uky.edu

Fin. POC: Paige Brown 859 257 3662 ukrfinvoices@uky.edu Alt. Fin. POC: Kim C. Carter ospa@uky.edu

(859) 257-9420

Statement of Work (SOW):

OBJECTIVE. Current chemical and biological agent resistant coatings fail to provide desired levels of contamination prevention, with penetration of threats into the coatings and, often, incomplete removal of those threats following decontamination. While these behaviors are well described for painted materials, there is a lack of understanding associated with the fundamental properties driving them. As a result, the design of coatings suitable to repelling chemical agents or to decreasing the logistics of decontamination presents a significant challenge. This work seeks to provide an understanding of the fundamental aspects of coating and thin film technologies focused on characteristics driving their repellency and retention behaviors when in contact with chemical and biological targets. Prior work, including much of the development and characterization work on these types of coatings and materials, has focused on wetting behaviors. The assumption behind this approach being that a lack of interactions with the surface will lead to reduced retention of threats. Recent work demonstrates the lack of correlation between these types of measurements. The proposed study seeks to address the lack of relevant information on and basic understanding of the principles driving retention of compounds by polymer materials to inform the development of coatings that will meet the needs of the CBD community.

Dr. Jonathan Pham received a PhD in Polymer Science and Engineering (2015) from the University of Massachusetts Amherst focusing on nanoparticle assembly, nano- and microscale mechanics, and surface tension driven bending deformations. During his graduate training, he was awarded a Chateaubriand fellowship to conduct research in the Physics and Mechanics of Heterogeneous Media laboratory at the ESPCI in Paris, France, where he focused on small scale fluid-structure interactions with microfluidics. In 2015, he was awarded a Humboldt postdoctoral fellowship to work at the Max Planck Institute for Polymer Research in Mainz, Germany. During this time, he focused several areas of soft interfaces including: biological cells interactions with soft, patterned surfaces; adhesion of small microparticles on soft polymeric materials; and the physics of how liquid and hydrogel droplets interact and impact surfaces. Jonathan Pham joined the University of Kentucky in 2017 as an assistant professor and leads the soft materials and interfaces group. Current projects are focused on liquid drop dynamics, friction, and adhesion related to polymeric surfaces on small length scales. To-date, he has authored 14 publications and has an H-index of 10.

General: The proposed work entails: This overall effort will synthesize and use a systematic series of polymer materials as a starting point for understanding the factors driving target penetration into and retention by polymer coatings. Here, the effort will be supported by traditional and novel imaging and characterization techniques in both static and dynamic approaches to provide additional insight into penetration points and contributing factors. The effort seeks to inform development of coating technologies offering reduced retention of chemical targets.

Task: Characterization of the Soft, Wet, & Sticky Traditional measurement techniques can overlook or ignore contributions of polymer behaviors, including the deformability of the materials and the mobility of free molecules within the polymer structures. The deformation of soft crosslinked polymers by the surface tension of water drops, similar to a liquid capillary meniscus has been demonstrated by this group. The fundamental impact of free molecules within polymer networks on droplet movement, migration of free molecules into and out of the materials, and on adhesion is not well understood. These are critical aspects for the development and design of repellent coatings and/or design of materials offering improved decontamination performance. Routes have been developed to provide soft polymer networks infused with controlled free molecules Cross-sectional images collected via confocal microscopy allow for quantification of the contact angles and hysteresis behaviors. Beyond contact angles and microscopic physics near the contact lines of soft polymeric systems, dynamics on the surfaces, including sliding and drop impact, will be investigated. The dynamics of free molecule contamination may offer insights into retention of certain chemical agents and/or routes for efficient surface decontamination.

Milestone/Metric: This task focuses on evaluation of a series of materials synthesized by the larger ongoing effort. Data collected under this task will provide feedback for the ongoing modeling effort as well as providing a systematic data set that can be utilized to inform directed coatings development.

Deliverable: This task will provide reports summarizing the performance and behaviors of the materials. These reports will serve to inform the ongoing modeling efforts. Comparisons of modeling output with these experimental results will be included.