Different Types of Nano Finishes in Textiles

Different Types of Nano Finishes in Textiles

Authors: Ayesha Shaikh
Bushra Rehman
Ummul Rifa Khan Syeda Farah Zaidi
Dept. of Textile Science
NED University of Engineering and Technology, Karachi, Pakistan

Introduction:

Nanotechnology has brought a revolution in textile industry. The “nanoscale” is typically measured in nanometers, or billionths of a meter (nanos, the Greek word for “dwarf”), and materials built at this scale often exhibit distinctive physical and chemical properties due to quantum mechanical effects. Nanotechnology is the manipulation and manufacture of materials and devices on the scale of atoms or small groups of atoms. Nanotechnology make it possible to manufacture lighter, stronger, and programmable materials that require less energy to produce and less waste than conventional materials. Nano finishes make fabrics work smarter—not harder. Nano finishes apply particles this small to fabrics, creating ultra-thin protective layers that don’t change the look or feel.

Nanotechnology:

• Nanotechnology focuses on arranging and controlling of nanoscale structures to incorporate into large material structures and components.
• Achieve the ultimate in precision: almost every atom in exactly the right place.
• Reduce manufacturing costs to little more than the cost of the required raw materials and energy.

Nanotechnology in Textile Finishing:

• Nanotechnology at the molecular level can be used to develop desired textile characteristics, such as high tensile strength, unique surface structure, soft hand, durability, water repellency, fire retardancy, antimicrobial properties.
• Coating the surface of textiles and clothing with nanoparticles is an approach to the production of highly active surfaces to have UV blocking, antimicrobial, flame retardant, water repellant and self-cleaning properties.
• Advances in Nanotechnology have created enormous opportunities and challenges for the textile industry.
• Nano Whiskers can make the fabric stain & water resistant Nano whiskers can keep the fabric breathable too unlike resins finishes.

Nanotechnology in textiles can be distinguished in three types:

1. Nanotechnology in fiber and yarn
2. Nanotechnology in E-textiles
3. Nanotechnology in coatings (Finishing)

By applying very tiny particles, known as nanoparticles, textiles can gain special properties like water resistance, flame retardant, stain protection, insect protection, self cleaning, UV blocking, and even antibacterial effects. Let’s explore some common types of nano finishes used in textiles.

Application of Nano Finishing in Textiles

Mechanism of Nano Finishing:

IN-SITU:

• Incorporation by swelling and closing
• Incorporation during filament extrusion
• Surface etching

EX-SITU:

• Pad-dry-cure using binder
• Surface modification and linking
• Electro spraying

Different Types of Nano Finishes Used in Textiles:

1. Water repellent and Water proof finishes
2. Self-cleaning finishes
3. UV protection finish
4. Anti-microbial finishes
5. Flame retardant finishes
6. Protecting finishes
7. Sensing finishes
8. Magnetic finishes
9. Conductive finishes

Above all nano finishes used in textiles are described below:

Water Repellent Finish:
Plasma Hydrophobic Finish:

• Plasma enhances attachment of finishing material.
• Monomers with required properties are used in plasma polymerization and sputtering.
• Silane compounds with alkyl groups and fluorocarbon monomers are used.

Super Hydrophobic Finish:

• Inspired by the roughness of leaves and insect wings, hydrophobic properties is develop by making nano surface roughness of silver nano particles.
• The air enclosed between gaps in surface enlarges water-air interfaces and minimizes water-solid interface.

Self-Cleaning Finish:
The dirt deposited on the surface is generally larger than the super hydrophobic nano coating applied hence, the dirt is deposited on tips. When water drop rolled over the dirt particle is captured and removed.

UV Protection Finish:

• The nano size particles are more efficient in absorbing and scattering uv radiation than conventional size particles because nano particles have larger surface area. Such as, Titanium dioxide and Zinc oxide.

  

Anti – Microbial Finish:

• Nano silver particles have relatively large surface area and high antibacterial effect. It also suppresses respiration and inhibits growth of microorganisms.
• The cotton and polyester fabrics are padded with nano sized silver, titanium dioxide and zinc oxide colloidal solution.
• Both natural and synthetic fibers are not resistant to microorganisms. Metallic ions and metallic compounds give sterilizing effect.

  

Flame Retardant Finish:

• Textiles with flame-retardant properties belong to a group of protective technical textiles that protect the wearers and textiles material from flame and heat.

Benefits:

• No adverse effect on colour, comfort, handle, and tensile strength of the treated fabrics.

Application Methods:

• Exhaustion, pad-dry-cure, back coating, laminating, sol-gel, and LBL self-assembly method.

Mechanism of flame retardant finish:
Carbon NANO Tube:

• Carbon nanotubes (CNTs) are also regarded as flame-retardant materials due to the formation of char layers acting as a heat barrier and thermal insulator.
• Due to the fibrous morphology of CNTs, their effect as a barrier needs high level of concentration compared with nano clays.
• Combination of CNT with clay nanoparticles has been also developed to enhance the flame-retardant properties

SiO₂:

• Silica nanoparticles or silica coatings onto polyester, cotton, and their blends has shown promising thermal stability and flame retardant properties.
• Prepared from waste agriculture products such as rice husk (RH-SNP), and their combination with organic borate as back coating on linen fabrics indicated the synergistic effect.
• The application of sol-gel method promotes the formation of a surface silica insulating barrier capable of enhancing the thermo-oxidative stability and flame-retardant properties.

  

Insect Protection Finish:

• Insect protection finishing can be prepared to provide the safety of wearer against various types of mosquitoes
• It protects human from the diseases such as malaria and dengue
• To produce mosquito nets and home textiles or used to protect textile materials such as carpets from moths regarded as moths proofing.

Mosquito repellent finish:

• Historically, the most common way of producing anti-mosquito textiles was through addition of anti-insect agents into spinning step, making insect repellent fibers with more permanent effects.
• Spraying, dipping, and pad-dry- cure methods are also used to impart insect-repellent properties into textiles
• A recent attempt has been made to modify N, N-diethyl-metatoluamide (DEET) for anchoring to cotton fabric.
• Prepared by nitration of DEET following by reduction of nitrated DEET . The modified DEET was then applied on cotton fabric through conventional pad-dry-cure method using DMDHEU based resin.
• In another study the reduced nitrated DEET was coupled with napthols using diazotization process to dye cotton fabric along with imparting anti-mosquito properties.
• Moreover, the same authors developed a reactive dye based on the insect-repellent agent DEET for dyeing of nylon 6 along with mosquito repellent properties.

  

Moth – Proof finish:

• Moth and carpet beetle, larvae are major causes of wool damage
• It is due to disulphide bonds breakage
• These species have special enzymes that can digest wool keratins
• With the advent of nanotechnology, incorporation of nanoparticles such as nano TiO2 has been developed as anti feeding compounds to protect wool fabrics against moths.
• It has been supposed that nanoparticles are physically adsorbed onto the cuticular lipids of insects, breaking their water barrier effect causing their subsequent death from dehydration.

Next Generation Nano Finishes:

NANO – Care:
Functions:

• It brings entirely carefree fabric with wrinkle resistant, shrink proof, water and stain repellant properties.

Fiber suitability:

• It is intended for use in cellulosic fibers.

Features:

• Superior stain, water and oil repellency.
• Resists wrinkles.
• Breathable fabric.
• Easy care.
• Nano-care withstands more than 50 home launderings.

NANO – Dry Functions:

• It is hydrophilic technology that imparts outstanding endurance of more than 50 home launderings.

Fiber suitability:

• It is intended for use in polyester and nylon (particularly in the field of sportswear that require perspiration absorbency).

Features:

• Moisture wicking.
• Retains breathability of fabric.
• Quick drying.
• Durable performance.

NANO – Touch

Functions:

• It gives durable cellulose wrapping over synthetic fiber in order to alter its properties.

Fiber suitability:

• It is intended for use in synthetics.

Features:

• Superior refinement in a blended fabric.
• Durable performance.
• Luxurious cotton-like hand.
• Easy care.
• Reduced static build-up.

Why Nanotechnology is being Used in Textile?

Conventional methods:

• Lower sustainability
• Reduce breathability
• Comfort

Nanotechnology:

• Large surface area-to-volume ratio
• High surface energy
• Smaller size
• High Durability

Future Trends Nanofinishing:

• Upgrading the existing nanomaterials and Nano treatment methods
• Producing multicomponent nanocomposites with synergistic effects
• Development of multi regular or irregular Nano structured surface roughness
• Incorporation of nanomaterials and nanocomposites into textile substrates
• New methods of fabrication of nanomaterials on textile surfaces

Conclusion:

Nanotechnology-based textiles will continue to emerge with new properties, functionalities, and applications transforming the concept of textile clothing from simple apparel and garments to sophisticated innovated smart multi functionalized wearable and technical substrates. Nano finishes are a great way to enhance the performance and durability of textiles without affecting their natural look and feel. The current trend in producing new nanomaterials and nanofabrication methods, modifications of the existing materials and techniques will be further advanced in future. Together with the progress in textile nano finishing sector, the need for ensuring the safety of the nano treated textiles against environment and human health will be also crucial. Nano finishes are the quiet revolution keeping you dry, fresh, and protected, one invisible particle at a time. As technology improves, we can expect even more innovative and useful nano finishes in the future, making fabrics smarter and more functional for everyday life.

References:

Share This Article!