The Importance Of Rinsing When Doing Laundry

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So Diffusiophoresis helps a lot getting stuff out of intra yarn pores but there`s still the fact that a long wash cycle is giving much better results than a short one.
After all both are followed by a rinse cycle, aren`t they?
IIRC in Japan they have some detergents merely based on nonionic surfactants which would not give an electrical difference between the micelles traped in the fibers and the rinse water.
How can they get away with it? Is it because nonionics penetrate intra yarn pores much better than the anionics discussed in the video?
 
Long wash cycles, diffusion and rinsing

I think I posted that video at some point on here...

Long wash cycles mainly perform better by giving more time for penetration.
The dirt gets broken down into smaller particles, thus encapsulated better by any tensides.
Thus again moved out of the fibres easier.

Further, chemical action like bleaching are outside of that effect and just need some time.
They are a plain chemical reaction and reaction rates depend mostly on concentration and temperature, number of reactions on time and rate.

And I don't think the charges play much role in a process based on diffusion.

Diffusion is mainly concentration based.
So charge of the surfactant isn't a factor in that.
It's just the concentration difference pulling into one direction.

I can think of several examples where manufacturers used this effect of the top of my head - not saying the knew what was going on:

- Miele used to have a "reactivating" stage at the end of the main wash in their W7xx series machines where they upped the water level from low to high.

- Mieles PowerWash system washes in an incredibly highly concentrated detergent solution and only dilutes to a normal concentration after all heating and cleaning is done.
That will use that concentration difference aswell.

- Electrolux machines in the EU for a long time used a dilution rinse before the first intermediate spin after the main wash if you selected certain rinse options (sometimes called "Sensitive", sometimes the normal Extra Rinse option or 2 or more additional rinses if selectable by number).

- Many machines in the US currently don't run interim spins after the main wash. I think WPs newest frontloaders aswell as ELux comes to mind.
 
My Kenmore Elite

fills higher after some time in the main wash. It will do the spray rinse as well as a deep rinse in addition to to more spray rinses. You can hear the pump cavitating depending on what you put in it during the normal cycle.
 
I vaguely remember about diffusion in chemistry class decades ago but at 3:25 she says "when you`re using anionic surfactants this creates an electric field that makes the micells migrate out of those intra yarn pores" which made me believe it`s more about the electric charge than just about a concentration difference.
 
I still don`t get the new and revolutionary part of the whole process, besides maybe the explanation of how it`s possible to get at least part of the intra yarn dirt out even in a short and cool wash.

I`m thinking of Kelvinator`s Magic Minute or any kind of preteating by hand for example. That`s nothing else than the attempt of getting more micelles and other chemicals in which are pulled out again in a later stage of the wash cycle.
In this case most of the diffusion happens in the mainwash instead of the rinse but it`s nothing new or groundbreaking.

I also don`t understand why there shouldn`t be a spin before the the rinse cycle and still take advantage of "diffusiophoresis"
IIRC Launderess mentioned several times that there has been an argument among laundry professionals going on whether a spin after the wash would press dissolved dirt further into fabrics or not.
I think if there is a chance that dirt is getting pressed deeper into the fibers then it would also be the case for micelles, which in turn would be even beneficial for diffusiophoresis, or am I missing something?

I`m wondering what impact a spin of something tie died right after the dye bath would have before rinsing. Couldn`t tell for sure but my best guess would be less color contrast as a result, which would translate into more micelles in intra yarn pores.
 
Interim Spins

A lot of new machines only perform the interim after the wash, and skips one between rinses. I would imagine this is for time savings and water savings. Clothes that already are retaining water will not require as much water to fill to a particular level.
I will say it again, I highly prefer the two shallow rinses with interim spins to TurboWash's spray and one deep rinse with a weaker interim spin. Others don't agree, but its a personal preference.
 
Finally got round to watching video in OP.

Found it interesting, but turned to reading matter on same subject instead.

https://cosmosmagazine.com/physics/coming-clean-the-physics-of-doing-the-laundry/

http://live.iop-pp01.agh.sleek.net/2018/04/28/physicists-dish-the-dirt-on-clothes-washing-mystery/

If am understanding correctly it is the change in electrical charge (caused by introduction of fresh water), that gets diffusiophoresis going. Obviously if rinse water is laden with detergent or soap there won't be such a great change because of what surfactants do....

As for debate between extraction (by wringing, spinning or whatever means) at once after washing versus not, you have this:

"The team also conducted model laundry experiments. The results showed that, after soaking a stained cotton fabric with detergent, a fresh water rinse cleans faster and more thoroughly than a rinse with detergent-filled water (see second video). Based on these findings, the researchers make several recommendations for optimizing the cleaning process. One of them is that fresh water should be added rapidly after thoroughly wringing out fabrics to remove detergent-saturated water."

https://www.automaticwasher.org/cgi-bin/TD/TD-VIEWTHREAD.cgi?87888

Laundry manuals going back to early 1900's advised housewives or anyone else doing the wash that things should be wrung or extracted before going into rinse. This flies counter to commercial laundries and others and their "straining dirty water through fabrics) by extracting after wash and between rinses.
 

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