Editing Hygroscopy (section)

==Research==
Several hygroscopic approaches to harvest atmospheric moisture have been demonstrated and require further development to assess their potentials as a viable water source.
* Experiments with fog collection, in select environs, duplicated the hydrophilic surfaces and hygroscopic surface wetting observed in tree frog hydration ([[Biomimetics|biomimicry]]). Subsequent material optimizations developed artificial hydrophilic surfaces with collection rates of 25&nbsp;mg H<sub>2</sub>O/(cm<sup>2</sup> h), more than twice the collection rate of tree frogs under comparable conditions, i.e. 100% RH (relative humidity).<ref name="Comanns2" />
* Another approach performs at lower 15–30% RHs but also has environs limitations; a sustainable biomass source is necessary. Super hygroscopic polymer films composed of biomass and hygroscopic salts are able to condense moisture from atmospheric humidity.<ref name="Comanns2" /> By implementing rapid sorption-desorption kinetics and operating 14–24 cycles per day, this technique produced an equivalent water yield of 5.8–13.3 L kg<sup>−1</sup> of sustainable raw materials, demonstrating the potential for low-cost, scalable atmospheric water harvesting.<ref name="Guo">{{cite journal |last1=Guo |first1=Youhong |last2=Guan |first2=Weixin |last3=Lei |first3=Chuxin |last4=Lu |first4=Hengyi |last5=Shi |first5=Wen |last6=Yu |first6=Guihua |title=Scalable super hygroscopic polymer films for sustainable moisture harvesting in arid environments |journal=Nature Communications |date=19 May 2022 |volume=13 |issue=(1):2761 |pages=Abstract |doi=10.1038/s41467-022-30505-2 |pmid=35589809 |pmc=9120194 |bibcode=2022NatCo..13.2761G }}</ref>

Hygroscopic glues are candidates for commercial development.  The most common cause of synthetic glue failure at high humidity is attributed to water lubricating the contact area, impacting bond quality. Hygroscopic glues may allow more durable adhesive bonds by absorbing (pulling) inter-facial environmental moisture away from the glue-substrate boundary.<ref name="Singla" />

Integrating hygroscopic movement into smart building designs and systems is frequently mentioned, e.g. self-opening windows.<ref name="Brulé" /> Such movement is appealing, an adaptive, self-shaping response that requires no external force or energy. However, capabilities of current material choices are limited.  Biomimetic design of hygromorphic wood composites and hygro-actuated building systems have been modeled and evaluated.<ref name="Zhan">{{cite journal |last1=Zhan |first1=Tianyi |last2=Li |first2=Rui |last3=Liu |first3=Zhiting |last4=Peng |first4=Hui |last5=Lyu |first5=Jianxiong |title=From adaptive plant materials toward hygro-actuated wooden building systems: A review |journal=Construction and Building Materials |date=10 March 2023 |volume=369 |issue=130479 |pages=Abstract |doi=10.1016/j.conbuildmat.2023.130479 |s2cid=256593092 |url=https://www.sciencedirect.com/science/article/abs/pii/S0950061823001903 |access-date=18 March 2023}}</ref>  
* Hygrometric response time, precise shape changes and durability are lacking. Most currently available hygro-actuated composites are inferior and exhibit fatigue failure well before that seen in nature, e.g. in pine cone scales, indicating that a better understanding of the plants' biological structures is needed.<ref name="Zhan" /> Materials composed of fluid-responsive active bilayer systems that can direct planned conformational hygromorphing are necessary.<ref name="Brulé" />
* Current composites require undesirable trade-offs between hygromorphic response time and mechanical stability that must also be balanced with changing environmental stimuli.<ref name="Zhan" />