530
M. Singh et al.
agriculture (used for crop protection), civil engineering (as reinforcement textile
for roads), medical and hygiene (bandages, surgical gowns and sutures), protective
clothing (firefighter clothes), sportswear, defence (bulletproof jackets), packaging,
etc. Looking at the broad spectrum of applications for which textiles are being used, it
is necessary to manufacture textiles with specifically designed surface properties like
wettability, increased adhesion, dyeability and softness (John and Anandjiwala 2009;
Wei et al. 2009). It is essential to understand that often natural or fabricated polymer
surfaces do not have the same compositions as the bulk phase. This difference in
surface properties can result from chemical reactions of surface molecules (like oxidation or sulphonation), microbial attack, adherence of environmental contaminants
like (dirt or soil) and low surface energy of molecular groups. Sometimes, physical
defects like scratches or abrasion can also lead to defunctionalisation of textile for a
particular application. Therefore, surface modification of textile surface is not only
preferable but also essential whether it may be merely to clean the surface or modify
it chemically or physically to alter the interactions with substrate and generate result
as per our requirement (Hoffman 1996).
Surface modification is the process of modifying material surface either by physical, chemical or biological methods to impart certain features which distinguish it
from the untreated one. Over the years, various surface modification techniques have
been employed for the alternation of textile surface properties which can be broadly
divided into physical, chemical, biological and mechanical methods (Fig. 1). The
physical processes involve treatment with active gases or radiations which can be
achieved by (a) deposition of molecules from active gases used during plasma treatment or flame spray treatment, (b) etching or oxidation of fabric surface with highly
accelerated ions generated during ion bean treatments, radiofrequency plasma discharge and gamma-ray treatments, and (c) cross-linking of surface molecules initiated
by free radical formation during UV treatment, corona discharge, etc. The chemical
surface treatment methods generally use wet chemical treatments for surface modification along with disinfection to remove microbes or soil and contaminants using
any or all four described methods: (a) dipping/coating/spraying of polymer solution
or surfactant, (b) desorption of surface-active compounds from bulk to surface, (c)
chemical treatment to modify fabric surface by various processes like oxidation,
sulphonation, chlorination, etc., and (d) chemical bonding of molecules like PEG
or sulphonating agents to fabric surface. Sometimes, surface modification has to be
performed by both physical and chemical methods jointly; it is called physicochemical methods. Mechanical means of surface modification involve roughening which
make the surface rough or porous and micromanipulation, i.e. using AFM probes
and scanning tunnelling microscopy. Biological processes of surface modification
are also used in case of biomedical applications by applying four different ways (a)
physical adsorption of biomolecules like peptides, proteins, ligands, etc., (b) physical
adsorption along with cross-linking of these biomolecules like enzyme attachment
to fabric surface, (c) chemical attachment of biomolecules to surface molecules and
(d) multiplication of cells and growth to convergence (Hoffman 1996; Jaganathan
2015).
M. Singh et al.
agriculture (used for crop protection), civil engineering (as reinforcement textile
for roads), medical and hygiene (bandages, surgical gowns and sutures), protective
clothing (firefighter clothes), sportswear, defence (bulletproof jackets), packaging,
etc. Looking at the broad spectrum of applications for which textiles are being used, it
is necessary to manufacture textiles with specifically designed surface properties like
wettability, increased adhesion, dyeability and softness (John and Anandjiwala 2009;
Wei et al. 2009). It is essential to understand that often natural or fabricated polymer
surfaces do not have the same compositions as the bulk phase. This difference in
surface properties can result from chemical reactions of surface molecules (like oxidation or sulphonation), microbial attack, adherence of environmental contaminants
like (dirt or soil) and low surface energy of molecular groups. Sometimes, physical
defects like scratches or abrasion can also lead to defunctionalisation of textile for a
particular application. Therefore, surface modification of textile surface is not only
preferable but also essential whether it may be merely to clean the surface or modify
it chemically or physically to alter the interactions with substrate and generate result
as per our requirement (Hoffman 1996).
Surface modification is the process of modifying material surface either by physical, chemical or biological methods to impart certain features which distinguish it
from the untreated one. Over the years, various surface modification techniques have
been employed for the alternation of textile surface properties which can be broadly
divided into physical, chemical, biological and mechanical methods (Fig. 1). The
physical processes involve treatment with active gases or radiations which can be
achieved by (a) deposition of molecules from active gases used during plasma treatment or flame spray treatment, (b) etching or oxidation of fabric surface with highly
accelerated ions generated during ion bean treatments, radiofrequency plasma discharge and gamma-ray treatments, and (c) cross-linking of surface molecules initiated
by free radical formation during UV treatment, corona discharge, etc. The chemical
surface treatment methods generally use wet chemical treatments for surface modification along with disinfection to remove microbes or soil and contaminants using
any or all four described methods: (a) dipping/coating/spraying of polymer solution
or surfactant, (b) desorption of surface-active compounds from bulk to surface, (c)
chemical treatment to modify fabric surface by various processes like oxidation,
sulphonation, chlorination, etc., and (d) chemical bonding of molecules like PEG
or sulphonating agents to fabric surface. Sometimes, surface modification has to be
performed by both physical and chemical methods jointly; it is called physicochemical methods. Mechanical means of surface modification involve roughening which
make the surface rough or porous and micromanipulation, i.e. using AFM probes
and scanning tunnelling microscopy. Biological processes of surface modification
are also used in case of biomedical applications by applying four different ways (a)
physical adsorption of biomolecules like peptides, proteins, ligands, etc., (b) physical
adsorption along with cross-linking of these biomolecules like enzyme attachment
to fabric surface, (c) chemical attachment of biomolecules to surface molecules and
(d) multiplication of cells and growth to convergence (Hoffman 1996; Jaganathan
2015).