Military PPE

Harrick Plasma → Applications → Materials → Textiles → Military PPE

To provide adequate protection against biological and chemical warfare agents, military personal protective equipment ( Military PPE ) must filter and/or degrade the toxic agent to safe levels. These processes are achieved by surface engineering of filter materials or the use of specialized coatings to optimize textile chemistry.

Plasma treatment can tune the pore size of filter materials to allow good breathability without sacrificing safety. Plasma treatment also prepares flexible surfaces for subsequent spray-, dip-, or spin-coating by removing organic materials and introducing functional groups (-OH). These functional groups improve the adhesion of specialized coatings to the PPE material.

In this application note, you will learn how Harrick Plasma’s plasma cleaners have been used in research to develop more effective military PPE.

Development of Novel Filter Materials Using Plasma Treatment

Military respirators require excellent filtration of airborne nanoparticles under 100 nm in size to protect the wearer from biological and chemical threats. Despite their good filtration abilities, many respirators are bulky and trap water vapor. This restricts the wearer’s natural evaporative cooling process, leading to heat exhaustion.

Cheng et. al. relied on Harrick Plasma’s equipment to create lightweight, breathable filters with tunable pore sizes. First, Cheng grew graphene on a copper (Cu) foil and transferred the graphene to a polycarbonate support membrane. After sealing large tears in the graphene via interfacial polymerization (IP), Cheng introduced nanopores into the graphene by oxygen plasma treatment in Harrick Plasma’s Expanded Plasma Cleaner. The nanopore size grew larger with increasing plasma treatment time, indicating the tunability of pore sizes for different filtration needs. This graphene filter successfully filtered silica (SiO₂) nanoparticles of size ~5-20 nm while permitting up to 75% air permeability for excellent breathability.

Figure 1: Creating nanopores in graphene using plasma treatment. Adapted from Chen et. al.

Learn more about the benefits of plasma treatment for filter development and military PPE in the references below.

Photocatalytic Degradation of Volatile Organic Compounds (VOCs) on Plasma Treated Plastics

Military personnel facing exposure to volatile organic compounds (chemical agents) require wearable materials which can degrade the chemical agent to safe levels. One promising degradation method is photocatalysis, in which UV radiation breaks down the chemical agent in the presence of a catalyst. Titanium dioxide (TiO₂) is a promising catalyst due to its low cost, commercial availability, and non-toxicity.

Krogman et. al. used Harrick Plasma’s Basic Plasma Cleaner in a photocatalytic degradation study of chloroethyl ethyl sulfide (CEES), a sulfur mustard simulant compound. First, Krogman plasma treated plastic sheeting to clean and hydroxylate its surface. Next, the authors sprayed alternating layers of PDADMAC and colloidal titanium dioxide (TiO₂) onto the functionalized plastic. This layer-by-layer (LbL) coating relied on the previous plasma treatment step for good adhesion and durability. CEES reacted with the PDADMAC /TiO₂ coating under simulated sunlight, decreasing the CEES permeation of the plastic by 95%.

Figure 2: Use of plasma treatment prior to spray coating of a photocatalytic layer for chemical agent degradation. Adapted from Krogman et. al.

Learn more about the role of plasma treatment in chemical exposure for military PPE research below.