june 4no 2-electro-induced water freeze_zchen

1、Electro-induced Water FreezeZhiqiang ChenAnnual meeting, HPSTARJun. 03-05,2015AcknowledgementDr. Bin Chen, HPSTARTheoratical and Experimental advicesFeng Ke, HPSTARTechnical suggestionsYuanjie Huang and NCP group members, HPSTARMrs. Yanping Yang, HPSTARDr. Junkai Zhang, HPSTARDr. Hengzhong Zhang, UC

2、 BerkleyDr. Jingyuan Yan, ALSDr. Jan Sun, NJUDr. Jinfu Shu and Dr. Qingyang Hu, CIWOutlineElectro-induced water freeze IntroductionImportance of waterPhase diagram Freezing mechanism Experiments and results Further workCO high pressure phasesImportance of WaterBiology Origin of life 70% weight of hu

3、man bodyEnvironment 70% of Earth surface 10% of Land massEnergy Heat reservoir Hydrogen sourceMaterials Solvent ReagentWATERICEMolecular structurefree molecularEquilibrium configuration of Waterdimer (H2O)2, ROO= 2.976OHO, Valence bond and H bond,Molecular Binding energy: 0.212eV; ROO= 2.764 in ice

4、Ih at T=253Kebinding q E DRooE 109V / mPhase diagramCrystal structureIhHex, P63/mmc a=4.518, c=7.356The three basic forms of ice crystal formed bycondensation from the vapor,(a) Needles or columns(b) plates(c) Snow flakes or starsDennison (1921)W. H. Barnes (1929) by SC-xrdCrystal structureVIICubic,

5、 pn3m a=3.344AVITetragonal, P42/nmca=6.181A, c=5.698ABridgman (1937)Walrafen et al. (1982) by X-rays Kuhs et al. (1984) by neutronsKamb (1965)Kuhs et al. (1984) by neutronsTheory of ice crystallizationAccording to the third law of thermodynamics, the disordered state should be aphase transition to a

6、 more ordered phase for an equilibrant state on cooling.Energy gained in such an ordering transformation is E and the entropy of disorderis S, so the transition occurs when free Energy(E TS) 0When an external E-field applied, the dipole momentum of liquid water can bealigned to reach more ordered st

7、ate accompanying with minimizing the entropyElectro-freezing above E=1V/nm (dynamic molecular simulation).Crystallization techniquesCooling an open vessel containingwater (Turner 1987; Knight 1996), The vapor is much more quickly and stably cooled on the coolingsurface under reduced pressure(Khusnat

8、dinov and Petrenko 1996) a polycrystalline ingot can be converted to a large high-qualitysingle crystal by zone refining(Bilgram 1973)a cooled seed crystal is gradually lifted from the liquid held at 0C (Czochralski technique)(a) Sapporo technique in which thecrystal is raised from the liquid,(b) Bi

9、rmingham technique in which the growth tube is lowered into cold antifreeze.Electrical discharge induced freezingExperimental setup and photos of ice in the shape of (a) dendrite and (b) needlesVapor temperature varies from -9 to -12C, d=8mm, V=8kVG. Mandal, P. Pradeep Kumar, Atmospheric Research 61

10、 (2002) 115123Square ice in graphene nanocapillariesPw=Ew/d=1GPa Ew2 GPa the most stable phases are semiconducting and insulating singly bondedthree-dimensionalframeworkandlayeredstructures. We also find a molecular Pbcmstructure which is more stable than the R3c structure proposed previously for th

11、e observed phase.Jian Sun et al, PRL 106, 145502 (2011)Phase transition of CO1.81G5.15G0.82G5.67G8.64G8.64GExperiments and plansBy high pressure upto 8.6 GPa with no E-field, no Pbcm asprediction but amorphous solids are observed.Even though HP (upto 8GPa) and E-field (upto 200V/50m)are applied simu

12、ltaneously, only amorphous patterns are observed.CO gas might be light sensitive, which needs to be fullycovered in black during transportation.Using ITO doped diamonds to continue this work over 60GPafor other predicted phases (frame work or layer phases).ITO glass (Indium-Tin Oxide)In2O3/SnO2=1:9Transmission andconductivity can be controlledFuture research projectsPhase transition of nano-confined water under P and E Liquid/vapor (dipole molecular) freeze und