Posted on 04/04/2018 8:05:57 PM PDT by MtnClimber
A fresh water rinse is just as important as washing in detergent for getting your clothes clean, according to physicists in the US and the UK. They claim that the rinse cycle plays a key role in removing dirt from deep within textiles, by setting up chemical and electrolyte gradients that draw it out. This could lead to the development of more efficient and environmentally friendly washing machines, they add.
Washing machines wash clothes with water mixed with detergent and then rinse them with fresh water before finally spinning them. Washing detergents are surfactants, compounds that lower the surface tension between liquids and other substances, making it easier for them to mix. When washing clothes, they help the water mix with and loosen dirt on the fabric. Conventional understanding is that rinsing then flushes the fabric and washes the dirt away.
Stagnant cores
But, there is a problem with this idea. In most fabrics there are tiny pores that do not allow any significant fluid flow inside them. According to Sangwoo Shin at the University of Hawaii, Patrick Warren of Unilever in the UK and Howard Stone of Princeton University, it should take several hours for micron-sized particles to diffuse out these micrometre-sized pores. Yet significant numbers of particles do leave these pores on much faster time scales. The question as to how this is possible is known in the washing industry as the stagnant core problem.
Looking at this problem, the trio noted that when detergent-saturated fabric is exposed to fresh water the surfactant molecules rapidly move out of the stagnant core. They hypothesized that the surfactant gradient established when the fabric is rinsed with a high concentration of surfactant within the fabrics pores and a low concentration in the surrounding water
(Excerpt) Read more at physicsworld.com ...
Why do you even use fabric softener?
.
I have to use the dryer through the winter, and the static build up is reduced a LOT when softener is used.
It smells nice, too.
Thanks-—I never used it so I was curious——I always considered it just another unnecessary product thrown at us to make money for a corporation.
.
In the really olden days, people used to collect urine, let it set around a while, then wash their clothes in it.
According to our guide, the laundry service would accept just about any kind of urine, but supposedly zebra and giraffe urine were greatly coveted. After washing laundry in urine and rinsing, the laundry would be “smoked” to help get rid of the ammonia/urine smell.
Thanks for the additional info. Hadn’t known that about the zebra and giraffe urine.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.