Thesis Details


Thesis Title: Durable Nanolayer Graft Polymerization of Textile Finishes: Waterproof and Antimicrobial Breathable Fabrics Via Plasma Treatment for Single Sided Treatments
Thesis Author: Rachel Lee-Tuck Davis
Abstract: Traditionally, chemical finishes are applied to textiles through a wet process which involved solvents, drying, and curing. One way that energy costs can be reduced while increasing quality of the product is through the use of plasma treatments to impart textile chemical finishes to fabrics. The purpose of this research was to use a nonthermal, atmospheric plasma treatment to impart a textile finish to a fabric surface that is both water repellent and antimicrobial. The water repellent treatment was single sided, so that the fabric is hydrophobic on the exterior of the garment while hydrophilic against the wearer’s skin, allowing the fabric to be breathable and more comfortable. The results of this research will benefit the textile industry by demonstrating a process that enables the production of high quality products at a lower cost of energy using a more environmentally friendly process. In this work, cotton/polyester blend fabric was treated with a water repellent treatment through activating the surface with plasma, depositing a vaporized fluorocarbon based monomer, (TG-10, UnidyneTM), then curing the finish with a second plasma exposure. The purpose of the first plasma exposure is to generate active free radicals on the surface which can react with the monomer, initiating free radical polymerization. The polymerization is completed through a second pass through the plasma, which allows the monomer to continue reacting to form a crosslinked network polymer nanolayer that is covalently bonded (grafted) to the fabric surface. The treated fabric samples were then evaluated for water repellency and durability to laundering. Once parameters were optimized to maximize the water repellent properties of the fabric, samples that showed the most effective water repellent treatment system were further treated with an antimicrobial agent. The antimicrobial treatment consisted of padding the fabric with a solution of diallyldimethylammonium chloride (DADMAC), a quaternary ammonium salt. Samples were padded with baths of different concentrations of DADMAC. The samples were then dried in an oven at low temperature (50°C), to prevent thermal curing, and then treated with a second plasma exposure of 10 or 20 seconds. The plasma treatment induced free radical polymerization of the DADMAC, causing a polymerized network to form on the fabric that should provide durable antimicrobial properties to the fabric. These antimicrobial properties were tested on K. pneumoniae and S. aureus. The results found that the water repellent treatment via plasma induced graft polymerization was successful in lowering the surface energy so that the fabric is more hydrophobic. Medium levels of monomer flow and plasma exposure time resulted in the most repellent samples. The treatment was durable to laundering, although some functionality of the water repellent was lost. This may be due to surface abrasion or the fluorocarbon chains re-orienting themselves on the surface of the fabric during laundering. The durability of the finish may be increased through a plasma pre-activation treatment, thereby generating free radicals on the fabric surface so that the monomers can react with the surface more efficiently. The results of the antimicrobial tests has shown that the treated fabric reduced the activity of both gram positive and gram negative bacteria by more than 99.994%, demonstrating that the antimicrobial agent can function effectively in combination with the water repellent. Future studies are suggested to include applying the antimicrobial agent before the water repellent finish, or dual applications with a single polymerization step. These procedural changes may increase the durability of the finishes, and may also increase the effectiveness of the water repellent on the antimicrobial treated fabric. In addition, crosslinking agents may be added to increase durability of the fluorocarbon finish.