RT&L FOCUS AREA(S): Warfighting Requirements (GWR) TECHNOLOGY AREA(S): Chemical/Biological Defense; Materials/Processes OBJECTIVE: Develop and scale textile coatings that repel both hydrophobic and hydrophilic liquids without the use of perfluoroalkyl or polyfluoroalkyl substances (PFAS) DESCRIPTION: Protective textiles for high-risk applications, such as Chemical/Biological Defense (CBD), first response, and healthcare must impart a high level of protection for the user. These textiles protect against a range of threats that can include toxic industrial chemicals (TICs), pharmaceuticals, blood, fuels, biological pathogens, and chemical warfare agents [1,2]. Per- and polyfluoroalkyl substances (PFAS) encompass a variety of compounds with Cn-F2n+1 bonds and are commonly used in repellent textile coatings. Long chains with carbon-fluorine bonds impart a high level of surface repellency against both water and oils by reducing surface energy [3]. Because of their repellent properties, uses for PFAS range from cookware to Chem-Bio (CB) protective clothing. However, increasing environmental and health concerns have led industry to remove PFAS from their processes. PFAS are known to persist in the environment, are challenging to remediate, and contribute to a variety of human health issues [4]. There are ongoing efforts to modify textile coatings, such as durable water repellent coatings (DWR) used on rain jackets and outdoor equipment [5,6], but the U.S. Department of Defense (DoD) is making efforts to remove all PFAS from military shoes and clothing/garments [6]. With the removal of PFAS as a component of repellent coatings, new textile coating technologies are needed that offer a high level of protection against both hydrophilic and hydrophobic compounds. Sprays, nanoparticles, other functionalized textile surfaces have been used to impart omniphobicity and lotus leaf properties with high contact angles against a variety of liquids, but more research is needed to develop and scale non-PFAS coatings that repel such a range of liquids [7-11]. There is a critical need to find coating technologies that can meet requirements without utilizing a carbon-fluorine bond. In order to replace or compete with PFAS textile coatings, new technologies must be: Omniphobic: Able to repel both hydrophilic and hydrophobic liquids, including water, oils, and toxic chemicals Scaleable: Able to scale coating manufacture to treat full textile rolls or garments Aqueous based solvent system: Textile manufacturers have strict limitations on flammable solvent use Material independent: Able to function on multiple textile types such as mixtures of natural, synthetic, stretch, and non-stretch fibers Durable: Coatings must have resistance to UV light, temperature cycling and the same if not better resistance to laundering and abrasion as currently used DWR technologies This SBIR topic solicits the following innovative technology requirements: T O oil rating (AATCC 118) 6A 8A after 1 laundering 6A 8A after 3 launderings 4A 8A spray rating (AATCC 22) 100 100 after 1 laundering 90 100 after 3 launderings 70 100 % change in textile air permeability (ASTM D737) 10 0 stretch (ASTM D2594) 10 0 weight (ASTM D 3770) 10 0 stiffness (ASTM D747) 10 0 burst strength (ASTM D 3787) 10 0 Tear strength (ASTM D 1424) 10 0 Flame resistance (ASTM F 1358) 0 0 Wicking 10 0 T = Target; O = Objective PHASE I: Phase I must demonstrate that a fluorine-free repellent coating can be applied to a fabric with no significant change to fabric properties. The table above details standard evaluations to assess performance, but other appropriate tests may be used as needed. For Phase I, the focus of material evaluation should be on repellency properties (oil rating, spray rating), weight changes, and loading of the active compound before and after coating. Phase II will address further textile properties, including laundering, but earlier material evaluations during Phase I are encouraged. An assessment of scaling capability for the repellent technology will be made, with special consideration for industry standard practices and limitations (i.e. solvent choice). Upon completion of Phase I, coated and uncoated textile swatches will be made available for independent evaluation. Two different types of coated textiles are required for Phase I (natural, synthetic, or a blend). PHASE II: Phase II will optimize and scale the repellent coating for both natural and synthetic textiles and blends thereof, including at least one fabric that has stretch. The objective is to scale the repellent coating so it may be used to treat 60 width fabric rolls. The coating must demonstrate no significant change to fabric properties, including flame resistance, stretch, burst and tear strength, drape and stiffness, wicking, air permeability, and color. The table above details standard evaluations to assess performance, but other appropriate tests may be used as needed. Phase II testing should also include durability assessments (stretch, burst, tear) before and after abrasion and laundering. Evaluations of omniphobicity must be performed along the length and width of the production to demonstrate uniformity. An assessment for manufacturing and commercializing the repellent technology will be made, including a complete cost assessment for the repellent coating production and application. Upon completion of Phase II, coated and uncoated textile rolls will be made available for independent evaluation. PHASE III: The coated textiles successfully demonstrated in Phase II will be integrated into Chemical/Biological/Radiological/Nuclear (CBRN) protective ensembles, Army Combat Uniforms (ACUs) and Flame Resistant Army Combat Uniforms (FRACUs). Textiles should be made in full width production; issues in garment manufacture that may arise should be addressed. PHASE III DUAL USE APPLICATIONS: Omniphobic coatings have wide applications to protect materials from corrosion and liquid. They are used in outerwear, sportswear, camping gear, civilian Personal Protective Equipment (PPE), construction, shipyards, etc. REFERENCES: 1. Mitchell, A., et al. (2015). "Role of healthcare apparel and other healthcare textiles in the transmission of pathogens: a review of the literature." J Hosp Infect 90(4): 285-292. 10.1016/j.jhin.2015.02.017 2. a) NFPA 1990 Standard on Protective Ensembles for Chemical/Biological Terrorism Incidents 2022 Edition, National Fire Protection Association (NFPA), Quincy, MA 02269, USA. https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=1990 . Note that the 2022 Edition of NFPA 1990 is a combination of Standards NFPA 1991, NFPA 1992, and 1994. b) NFPA 1994 Standard on Protective Ensembles for Chemical/Biological Terrorism Incidents 2001 Edition, National Fire Protection Association (NFPA), Quincy, MA 02269, USA. http://www.disaster-info.net/lideres/english/jamaica/bibliography/ChemicalAccidents/NFPA_1994_StandardonProtectiveEnsemblesforChemicalBiologicalTerrorismIncidents.pdf 3. Gluge, J., et al. (2020). "An overview of the uses of per- and polyfluoroalkyl substances (PFAS)." Environ Sci Process Impacts 22(12): 2345-2373.Schellenberger, S., et al. (2019). "Highly fluorinated chemicals in functional textiles can be replaced by re-evaluating liquid repellency and end-user requirements." Journal of Cleaner Production 217: 134-143. 10.1016/j.jclepro.2019.01.160. 10.1039/d0em00291g 4. Environmental Protection Agency. (December 21, 2021). Our Current Understanding of the Human Health and Environmental Risks of PFAS. EPA.gov. https://www.epa.gov/pfas/our-current-understanding-human-health-and-environmental-risks-pfas 5. Patagonia. (July 15, 2016). An Update on Our DWR Problem. Patagonia.com. https://www.patagonia.com/stories/our-dwr-problem-updated/story-17673.html 6. S.1605 - 117th Congress (2021-2022): National Defense Authorization Act for Fiscal Year 2022, Section 347. (2021, December 27). https://www.congress.gov/bill/117th-congress/senate-bill/1605/text 7. Cirisano, F. and M. Ferrari (2021). "Sustainable Materials for Liquid Repellent Coatings." Coatings 11(12): 1508. 10.3390/coatings11121508 8. Mohseni, M., et al. (2021). "Non-fluorinated sprayable fabric finish for durable and comfortable superhydrophobic textiles." Progress in Organic Coatings 157: 106319. 10.1016/j.porgcoat.2021.106319 9. Rashid, M. M., et al. (2021). "Recent advances in TiO2-functionalized textile surfaces." Surfaces and Interfaces 22: 100890. 10.1016/j.surfin.2020.100890 10. Kwon, J., et al. (2020). "Micro/Nanostructured Coating for Cotton Textiles That Repel Oil, Water, and Chemical Warfare Agents." Polymers (Basel) 12(8). 10.3390/polym12081826 11. Ye, Z., et al. (2021). "Textile coatings configured by double-nanoparticles to optimally couple superhydrophobic and antibacterial properties." Chemical Engineering Journal 420: 127680. 10.1016/j.cej.2020.127680 KEYWORDS: PFAS, Non-PFAS, liquid repellency, fabric coatings, textile, Individual Protection
