Cotton Fabric That Absorbs Water From Air?

We know that moisture in the air is 2% in liquid form and 98% in vapor form. This ratio improves a bit - by another 1% or so - in favor of liquid water when a mist or fog rolls around.
For some reason, humanity has continued to focus on capturing the liquid water in air while there is no research on capturing the water that exists as vapor.

Now word comes of a new polymer that does just that.

What's a polymer?

A Polymer (multiple copies of the same unit
Source - ec.europa.eu

Covalent Bond
Source - en.wikipedia.org

A polymer is a compound whose structure is characterized by copies of the same units connected by covalent chemical bonds. A polymer, thus, is a collection of a number of copies of the same unit. 
The covalent bond is the sharing of two electrons between a carbon and a hydrogen atom that each contribute one electron to the coupling.
The New Polymer PNIPAAm

PNIAAm cotton fabric
Left (closed structure at high temperatures)
Right (open structure at low temperatures)
Source - Endoven University

Researchers at Netherland's Endoven University of Technology and at Hong Kong Polytechnic University have together created a new polymer they call PNIPAAm.
When this polymer is applied to cotton fabric, like a cotton shirt, the resulting combination is much more absorbent of liquid water from the air, than is the cotton alone.
The combination can absorb as much as 340% of the cotton weight of water. Cotton alone absorbs about 18% of its weight of water.
Key area of continuing research is the temperature at which the combination starts absorbing and releasing water and building actual clothing to check how the results from the test-beds pan out.

Freshwater and Radio Waves = A Security Tool!

We depend on adequate supplies of freshwater for our food, energy, health and every other artificial creation of ours. Now, with advances in science and technology, freshwater is also key to our security needs.
Full Body scanners at Airports

Image from Full Body Scanners
Source - en.wikipedia.org

Full Body Scanner Equipment
Source - au.ibtimes.com

Transportation authouroties around the world have adopted a tool, the full body scanner, to ensure that no travelers take board prohibited items on board aircraft, trains and other mass transportation vehicles.
There are many technologies used to create images that can reveal prohibited items.
Terahertz Radiation

Terahertz radiation band
Source - teranova-ist.org

Light with wavelength between 300GHz and 10THz is known as Terahertz Radiation.
This radiation exists naturally and falls between infrared and microwave radiation.
A characteristic quality of Terahertz radiation is its ability to penetrate clothing and the human body but only to a very limited extend - freshwater just below the human skin stops and absorbs particular terahertz radiation
Absorption by Freshwater 

Terahertz Radiation absorbed by water vapor
Source - en.wikipedia.org

One form of body scanner works by firing radio waves of Terahertz length onto the human body and capturing the pattern of reflected and absorbed waves.
This pattern creates a body image of the kind full body scanners create to identify the existence of banned items.
As most metals do not absorb terahertz radiation, their existence can be confirmed in the pattern and the image. As most banned items are made of metals, the pattern can identify items hidden in clothing that could be one of the items banned from being transported on planes and trains.
Commercial Use of Terahertz Radiation

A Custom Clothing Machine
Source - digitalstyledigest.com

The first commercial application of freshwater-based body scanners is a set of machines that have been deployed in some specialty clothing stores.
These machines create an exact outline, in 3-D of the human body so that fitting clothes, for each of our individual body contours, can be found or manufactured.
These machines fire radio waves in the Terahertz range and catch the returning waves to build a true 3-D outline of a body.

Can terahertz radiation be used to locate new sources of freshwater?