Saminathan Ratnapandian

Plasma processing
Traditional wet chemistry
Medium	No wet chemistry involved;. treatment by excited gas	Water based
Energy	Electricity – only free electrons heated (<1% of system mass)	Heat – entire system mass temperature raised
Reaction type	Complex, multi-functional and simultaneous	Relatively simpler, well established

Reaction location	Surface specific, unaltered bulk properties	Bulk of material is usually affected
Potential for new processes	High, rapidly developing field	Low technological growth
Equipment	Experimental, laboratory and prototype, rapid development	Mature, slow evolution
Energy consumption	Low	High
Water consumption	Negligible	High

Consistent with the above discussion, treatment of wool with plasma has been reported to affect the lipid layer and surface cuticle without changing the bulk properties. This results in higher wettability and increased dye up-take, leading to improvements in the depth of shade and evenness. The available literature relates only to different classes of synthetic dyes [157-159]. It has also been suggested that intrinsic dye hydrophilicity is a deciding factor in this improvement [160]. Hence atmospheric pressure plasma pretreatment of wool was expected to improve padding with natural dyes.

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