Plasma Technology for Medical Textile Applications

Plasma Technology Applications In Medical Textiles

Dr.G.ThilagavathiDept of Textile TechnologyPSG College of TechnologyCoimbatore

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What is a Plasma ?

• States of Matter

– Solid, Liquid, Gas, Plasma

What is a Plasma ?

• A plasma is a gas containing charged and neutral species

• Generated by application of an electric field

• It requires energy to sustain a plasma

• More than 90% of the apparent universe is in the plasma state

Some more Plasmas

Low pressure (Vacuum)

Atmospheric pressure

TechnologicalPlasmas

Glow DischargeGlow Discharge

Corona dischargeCorona discharge

Atmospheric pressure plasmas

Atmospheric pressure plasma jetAtmospheric pressure plasma jet

Dielectric Barrier DischargeDielectric Barrier Discharge

Corona Discharge

• Generated between two electrodes of different sizes

• Corona- series of rapid, non-uniform, non-arcing discharges

• Plasma density drops off rapidly with increasing distance from the electrode

Dielectric Barrier Discharge

• Between two flat electrodes covered by dielectric plate

• Dielectric plate terminate the arcs rapidly that form between the electrodes

Glow Discharge Plasma

• Obtained at low pressures, typically < 10 mbar

• Generated by antennas, fed with electromagnetic fields at freq of 40 kHz

Atmospheric pressure plasma Jet (APPJ)

• Generated between concentric electrodes and blown as a jet continuously

Low pressure (Vacuum) Plasmas

Microwave driven

Inductively coupled

Capacitively coupled

Vacuum Plasma

• Created under vacuum pressure

• Closed system

• Can be barrier discharge, Jet etc

• Creates large volume glow plasma

Vacuum & Atmospheric plasma

Vacuum• Easy to create• Large volume• Batch process• Capital intensive• High running cost

Atmospheric• Difficult to create• Smaller volume• Continuous process• Low cost• Low running cost

Technologically Preferable

Why Plasma Treatment of Textiles ?

• It is a surface treatment

• Does not affect the bulk properties

• Eliminates liquid solid interaction

• Versatile and uniform treatment

• Environmental friendly process

DISADVANTAGES

Expensive Slow

Plasma Surface Engineering

Some different plasma gas effects on textiles

Argon - Increased surface roughness

Oxygen - Modification of surface chemical groups - Improved wettability

Fluorocarbons - Polymerization - Improved repellencyAmmonia, Carbondioxide - Modification of surface chemical groups

Modification using inert gas Plasma

1. Etching/Cleaning Inert gases (Ar, He etc) are

used. Break down weak covalent

bonds through bombardment with high energy particles

Detachment of low molecular weight species

Clean surface generation

Modification using inert gas Plasma

2. Activation Breaks down weak

bonds Formation of active

sites on the textile surface

Modification using inert gas Plasma

3. Grafting

Radical species present in the plasma may be directly grafted onto the polymer surface

Modification using inert gas Plasma

4. Polymerization

• Plasma enhanced chemical vapour deposition

• Thickness of coating can be varied by changing the experimental conditions

Plasma applications in medical textiles

• Cleaning• Sterilization• Surface modification for - Better adhesion of growing cells

- Attachment of growth promoters - Attachment of bioactive molecules for antimicrobial action

• Stain repellency of medical gowns, hospital clothing

Applications of Plasma-Textile Interactions

ADHESION PROMOTION

• Many polymers have a low to medium surface energy—examples include polypropylene, polyethylene and Teflon.

• Difficult to effectively apply adhesives or coatings.

• Oxygen plasma increase hydrophilicity => Improve adhesive bonding

– For example, plasma processing can increase the surface energy of polypropylene from 29 to 72 dynes/cm

Applications of Plasma-Polymer Interactions

HYDROPHILIC PROPERTIES

• A specially developed plasma activation process can be used to make a substrate surface hydrophilic. This permanently hydrophilic character can impart to woven or nonwoven textiles the capability to be used as blood filters or filtering membranes for various applications, including microfiltration components for dialysis filter systems.

Stain repellent finishing

• Stain repellency is required for leisure suits, safety clothes and surgical gowns

• Technique used - Plasma grafting and plasma polymerisation

• Hydrocarbon and silicon based repellents repel only water

• Fluorocarbon based repellents repels both oil & water

Bio compatibility

• Ability of the material to perform with an appropriate host response in a specific application

• Interaction between Biomaterals and tissues& cells(cyto compatibility)

• With blood(haemo compatibility)

• Biological responses(inflammation ,thrombosis and healing)

Applications of Plasma-Polymer Interactions

BIOCOMPATIBILITY

• Plasma activation of surfaces to prepare them for cell growth or protein bonding is another important application.

• Examples of in vivo uses includes use of plasma to enhance the biocompatibility of implants by treating the surface of a device to increase the adherence of a hemocompatible coating. Among the applications in this domain are vascular grafts, lenses, and drug-delivery implants. When required, surfaces can also be modified to decrease the bonding of proteins.

Surface Engg of biomedical Textiles

• 5 surface Engg Examples

• 1.Stain –repellent finishing-surgical Gowns

• Plasma based hydrophobisation

Bio compatibility/optimised cell growth

• Cells attach with the substrate via surface receptors on the cells ,which interact with proteins adsorbed on the surface of the sustrate

• -Hydrophyllicity-cell attachment-• functional groups alter the cell adhesion capability• Cell adhesion capacity -corneal epithelial cell

attachment and growth-ammonia plasma treatment to artificial corneas

Biocompatibilty/unspecific protein adsorption /Biofouling

• Contact of synthetic materials with biological fluids leeds to unspecific adsorption of proteins

• Hence bacteria also adhere to surface due to proteins

• Eg-,blocking of catheters,Plaque on teeth• PEGylated surfaces reduce biofouling• Amine groups on PET

Biocompatibilty/Immobilisation of Ligand-receptor systems

• Enzymatic reactions—controlled affinity between substrate and enzyme for biosensors

• Wound healing non woven pads-Immobilise growth factors-Biotin/streptavidin was used

• To attach biotin-presence of amino groups • Generation –plasma treatment with Ammonia as

process gas

Bio compatibilty/Antibacterial Properties

• -Metals and metal salts-silvaer• Plasma based coatings –Chitosan Grafted

on to plasma functionalised ppolymer surfaces if carboxyl groups are generated

• Deposition of silver by magnetron sputtering technique

• Oxygen plasma treatment prior to sputeering enhances adhesion

EXPERIMENTAL STUDY ON DUAL ANTIMICROBIAL AND BLOOD

REPELLENT FINISHES FOR COTTON FABRICS

Neem extract preparation

Application of antimicrobial finish

Application of blood repellent finish

Fluroploymer treatment

METHODOLOGY

Sputter deposition of Teflon

Antimicrobial efficacy of neem treated (1) fluropolymer finished and (2) Teflon finished fabrics

Effect of time variations on the repellency properties

Effect of power variations on the repellency properties

FT-IR Spectrum of plasma treated and untreated samples

X-Ray diffractogram of untreated samples

X-Ray diffractogram ofTeflon sputter deposited samples

SEM Micrographs

Neem treated Fluropolymer treated

Teflon treated

THANK YOU