所庆50周年系列学术活动－学术报告：Water, Energy and Life: Fresh Views from the Water’s Edge
学术报告：Water, Energy and Life: Fresh Views from the Water’s Edge报 告 人：Gerald H. Pollack, PhD,
Department of Bioengineering, University of Washington
报告时间：12月7日（周一）下午2:30
报告地点：学术活动中心102会议室
报告摘要：
The impact of surfaces on the contiguous aqueous phase is generally thought to extend no more than a few water-molecule layers. We find, however, that colloidal and molecular solutes are profoundly excluded from the vicinity of hydrophilic surfaces, to distances typically several hundred micrometers. Such large zones of exclusion have been observed next to many different hydrophilic surfaces, and many diverse solutes are excluded. Hence, the exclusion phenomenon appears to be quite general.
To test whether the physical properties of the exclusion zone differ from those of bulk water, several methods have been applied. NMR, infrared, and birefringence imaging, as well as measurements of electrical potential, viscosity, and UV-VIS and infrared-absorption spectra, collectively reveal that the solute-free zone is a physically distinct, more ordered phase of water. It can co-exist essentially indefinitely with the contiguous solute-containing phase. Indeed, this unexpectedly extensive zone may be a candidate for the long-postulated “fourth phase” of water considered by earlier scientists.
The energy responsible for building this charged, low entropy zone comes from light. We found that incident radiant energy including all visible and near-infrared wavelengths induce exclusion-zone growth in a spectrally sensitive manner. IR is particularly effective. Five-minute exposure to radiation at 3.1 μm (corresponding to OH stretch) causes exclusion-zone-width increase up to three times. Apparently, incident photons cause some change in bulk water that predisposes constituent molecules to reorganize and build the charged, ordered exclusion zone. We found also that such photons can power the flow of water through small hydrophilic tubes, with no additional source of energy.
Photons from ordinary sunlight, then, may have an unexpectedly powerful effect that goes beyond mere heating. It may be that solar energy builds order and separates charge between the near-surface exclusion zone and the bulk water beyond — the separation effectively creating a battery. The resemblance to the first steps of photosynthesis is evident. Indeed, this light-induced action would seem relevant not only for photosynthesis, but also for all realms of nature and engineering involving water and interfaces, and also for biology, where much or all of the cell’s water may be structured. The implications are amply discussed in http://uwtv.org/programs/displayevent.aspx?rID=22222 and http://www.i-sis.org.uk/liquidCrystallineWater.php and will be presented in the lecture.
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