Novel Methods of Synthesis and Deposition of Silica Nanoparticles for Textile Applications

Abstract

This dissertation investigates the optimal conditions for producing Silica Nanoparticles (SNPs). The SNPs are used to produce photonic crystals (PC) on glass and textile substrates, which modify incident white light and create coloured coatings without the need for dyes or pigments. This work provides new insights in two main areas. Firstly, the work extends and validates the Solvent Varying Technique (SVT), which was published in 2016 and provides a simple method for the production of uniform batches of SNPs of a target average diameter. SVT is a relatively new modification of the more established Stöber method and allows the fabrication of SNPs by only varying the volume of ethanol in the recipe. The relationship between particle diameter and ethanol volume is further investigated over an expanded range of initial ethanol volume. One finding from this work is that the SNPs were sensitive to the concentration of ethanol; hence models have been suggested that predict the SNP diameter for various volumes of solvent. It has been shown that different concentrations of ethanol also affect the final colour appearance of the photonic crystal films (ΔE*(ab) = 49.83). Secondly, although the SV method can produce uniform SNPs, the recipes may not be optimum and leave unused reactants in the SNP solution. This can influence the SNP diameters over time. A post-processing method that improves the homogeneity of SNPs is described. The post-processing (centrifuge and replacement of solvent) of SNPs has been proposed as an effective method of reducing unused reactants identified on the original SNPs. The processed SNPs exhibit more stable diameters (188.73±1.33nm) during increasing storage times and demonstrate better morphology. The colour intensity of the coloured fabrics coated using the post-processed SNPs have also been improved (ΔE*(ab) = 19.82).

Date of Award	1 Aug 2018
Original language	English
Awarding Institution	The University of Manchester
Supervisor	William Kennon (Supervisor) & Huw Owens (Supervisor)