A Computer Colour Matching (CCM) Study on Non-aqueous Reactive Dyeing of Cotton Fabric with Rhamnolipid (RL) Microbial Biosurfactant-Based Reverse Micelles

The feasibility of computer colour matching (CCM) of rhamnolipid-based reverse micellar dyeing system on cotton fibre in octane media has been investigated and compared with that of conventional water-based dyeing system. Calibration results confirm that the calibration curves of both systems are linear in structure. Reflectance curves reveal that both water-dyed and RL octane-dyed standard and batch samples are identical in shape without any peak shift and alteration of colour properties. The actual colour matching results of RL octane reverse micellar dyeing system are close to theoretical prediction with percentage difference less than 25%, verifying the applicability of CCM on RL reverse micellar dyeing system. RL octane-dyed samples can achieve good to excellent levelness, washing and rubbing fastness, which are comparable to that of water-dyed samples. Further experiments have been conducted to analyse the zeta-potential surface charge, particle size distribution and Raman spectra of RL. Volatile organic compound (VOC) detection and solvent recovery have also been conducted. Experimental results reveal that the leakage of octane solvent is between 2 and 3 ppm which is at acceptably low level whilst more than 98% of octane can be recovered for further use after the RL reverse micellar dyeing process, validating the environmental friendliness potential of the RL octane reverse micellar dyeing system.