Investigating aluminum salt containing hydrogels in water versus sweat mimics

Abstract

Aluminum salts are used in a wide variety of applications including water treatment, clay ceramics and antiperspirants/deodorants. Their unique ability to interact with sweat components to form a sweat plug has been widely studied as well as debated over the years. Industry has moved from traditional AlCl₃ salt to zirconium-aluminum-glycinate (ZAG) salts owing to the irritation and yellowing caused by AlCl₃. Although people have studied aluminum chemistry a systematic study of aluminum salts in relation to sweat plugs has not been studied. Herein, we have studied a range of Al and ZAG salts as a function of pH. Specifically, we have probed into how hydrolysis chemistry impacts Al-Keggin polymerization of salts in water versus a sweat mimic. We observed how pH plays a critical role in shifting equilibria of Al-Keggin polymers in various salts. This study will provide guidance to optimize newer salts and to develop novel metal-mediated hydrogels for application in sweat chemistry.

Graphical Abstract

Keywords:

• Hydrolysis
• aluminum chemistry
• aluminum chloride
• zirconium-aluminum-glycinate
• antiperspirants
• deodorants

Acknowledgements

The authors thank Procter & Gamble Company (Cincinnati, OH, USA) for financial support and special thanks to Dr. Allison Talley and Dr. Jacqueline Thomas for valuable discussions on NMR experiments. The authors would also like to acknowledge NSF-MRI grant CHE-1726092 that funded the Bruker AVANCE NEO 400 MHz NMR spectrometer on which the liquid-state NMR experiments were performed.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Procter and Gamble.