Naked Science Forum

Non Life Sciences => Chemistry => Topic started by: nudephil on 18/09/2020 20:28:16

Title: Why does linen hung out on the line in the air smell so lovely?
Post by: nudephil on 18/09/2020 20:28:16
Ros sent us this question:

Why does linen hung out on the line in the air smell so lovely?

Can anyone answer?
Title: Re: Why does linen hung out on the line in the air smell so lovely?
Post by: Bogie_smiles on 18/09/2020 22:44:00
Possible contributor, maybe a fragrant fabric softener was used, or even maybe just the visual whiteness in the sun triggers a pleasant reaction in the brain? a dopamine spike?
Title: Re: Why does linen hung out on the line in the air smell so lovely?
Post by: evan_au on 18/09/2020 23:00:35
For me and my dog, it's just nice to get outside and see the sun and sniff flowers (oops - overlap with Bogie_smiles).

I don't know if it is true, but I heard that in the USA, having a clothes line is almost an admission of poverty...
- It's like a Hollywood meme - if you want to show that someone is poor, show their clothes-line...
- Everyone who can afford it uses a clothes dryer (and that is certainly sensible if there is snow outside!)
- According to that rumor, most of our US readership wouldn't know...

Title: Re: Why does linen hung out on the line in the air smell so lovely?
Post by: alancalverd on 19/09/2020 00:13:12
This has been the subject of a lot of commercial research since washing machines and driers were invented, and so far with negligible success, though the prize for a manufacturable answer would be unimaginable riches. If  anything, conditioners and the like make linen smell worse than plain detergent and a good rinse.

However https://test-dpc.com/how-line-dried-laundry-gets-that-fresh-smell/22696/  summarises a recent academic investigation that suggests solar ultraviolet stimulates the production of pleasant-smelling aldehydes and ketones in airdried washed towels. 
Title: Re: Why does linen hung out on the line in the air smell so lovely?
Post by: Bored chemist on 19/09/2020 01:13:05
There was a report that it was due to the reaction of the fabric with  PAN
https://en.wikipedia.org/wiki/Peroxyacetyl_nitrate

No idea if it is true,
Title: Re: Why does linen hung out on the line in the air smell so lovely?
Post by: alancalverd on 19/09/2020 09:33:20
 
Quote
It is a secondary pollutant present in photochemical smog........It is a lachrymatory substance, meaning that it irritates the lungs and eyes

Not what I'd call a fresh-air smell, but chacun a son gout.   

Perfume chemistry seems to be a weird combination of  human physiology, psychology and happenstance. IIRC you can stroke a ferret with a lump of raw sheep wool and end up with a "seductive" musk fragrance.  So maybe hanging the washing in sunbaked smog really does work. I can see the advert now: "My underwear smells like Los Angeles in June, all year round...."  though the present hint of wood smoke might affect sales.
Title: Re: Why does linen hung out on the line in the air smell so lovely?
Post by: Bored chemist on 19/09/2020 11:42:45
Not what I'd call a fresh-air smell
Nor did I
However, the volatile materials that it produces by reaction with cellulose are a different thing entirely.
Title: Re: Why does linen hung out on the line in the air smell so lovely?
Post by: alancalverd on 19/09/2020 12:51:50
Aha! Maybe folk have ignored the elephant in the room: it's not just the air but also the material substrate that matters! So what works for cotton and linen may not work for nylon. I'll look out my old polyamide and terephthalate glad rags (oh God - the smell of the Sixties!) and off to Copenhagen with a null hypothesis.
Title: Re: Why does linen hung out on the line in the air smell so lovely?
Post by: Bored chemist on 19/09/2020 13:13:20
Maybe folk have ignored the elephant in the room:
It may be an elephant in the room, but it's "linen" in the title of the thread.
Title: Re: Why does linen hung out on the line in the air smell so lovely?
Post by: alancalverd on 19/09/2020 13:23:02
Most household "linens" are not linen. If you look at "linens limited.com" you will find hundreds of soft materials for home use and wear, all called "linens" but not one of them made from flax! 
Title: Re: Why does linen hung out on the line in the air smell so lovely?
Post by: Bored chemist on 19/09/2020 13:55:47
Most household "linens" are not linen. If you look at "linens limited.com" you will find hundreds of soft materials for home use and wear, all called "linens" but not one of them made from flax! 
Feel free to report them for fraud.
The point remains, it's the cellulose that's responsible for the "sun dried" smell.