Dispersion Stabilization of Titania Nanoparticles for Textile: Aggregation Behavior and Self-Cleaning Activity

Abstract

The effect of various dispersion stabilization parameters on particle size, stability, and self-cleaning activity of titania aqueous dispersion was investigated with a focus on stability during preparation, storage, and introduction of fabric in the dispersion. Effect of parameters such as sonication, high-speed mixing, pH, and addition of ionic and nonionic dispersants was studied. The degree of surface charge on titania influences its stability and depends on the type of pH and dispersant. The stability of titania dispersion with the immersion of cotton, was also found to be a strong function of pH, dispersants and their combination. With the immersion of cotton in the dispersion ξ potential was >40 mV in the pH range of 1–3, and then gradually becomes close to zero in the pH range 4–7, then decreased further with the increase in pH. In the study of combined effect of pH and dispersants, influence of pH on ξ potential was independent in case of ionic dispersants and addition of nonionic dispersant has significant pH dependence. Self-cleaning activity (SCA) of titania-treated cotton fabric was quantitatively assessed by a standard method known as stain degradation assessment (SDA) method. SCA was highest at pH 2 followed by that at pH 10 and 12. In the presence of cationic dispersant, CTAB, ξ potential was >50 mV before and after cotton immersion and high SCA was obtained, however, in the presence of sodium salt of PAA, stable dispersion was obtained, but SCA reduced.

Keywords:

• Agglomerates
• nanoparticles
• photocatalyst
• self-cleaning activity
• stability
• titanium dioxide

Acknowledgments

The authors acknowledge partial financial support from the Department of Science and Technology, Government of India and Resil Chemicals P Ltd., Bangalore. N. Goyal also acknowledges fellowship from University Grant Commission.

Notes

Note: *pH of as-prepared dispersions.

Note: pH value of the dispersion was measured after the addition of respective dispersant.

Note: Titania conc.0.5% w/v; All titania dispersions were sonicated at frequency 35 kHz for 60 minutes.

Notes. ^#Values outside perentheses indicate % Decrease in K/S after UV exposure.

*Values in perentheses indicate K/S value.

Note: s.

^#Values outside perentheses indicate % Decrease in K/S after UV exposure.

*Values in perentheses indicate K/S value.