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Investigation on surface tension of nanoscale water
나노스케일 물의 표면장력 연구

DC Field Value Language
dc.contributor.advisor제원호-
dc.contributor.author권소영-
dc.date.accessioned2017-07-19T06:07:56Z-
dc.date.available2017-07-19T06:07:56Z-
dc.date.issued2015-08-
dc.identifier.other000000056910-
dc.identifier.urihttp://dcollection.snu.ac.kr:80/jsp/common/DcLoOrgPer.jsp?sItemId=000000056910-
dc.description학위논문(박사)--서울대학교 대학원 :자연과학대학 물리·천문학부,2015. 8. 제원호.-
dc.description.abstractSurface tension plays an important role in nanoscale vapor-liquid phase transition such as condensation, evaporation of nano water meniscus or bubble. The measured and theoretical values due to the formation of it have been disagreed and it was been debated whether the surface tension defined in macroscopic scale is applied the same in nanoscale. However surface tension remain large unknown and imperatively need to be better understood. The capillary rise
method is the oldest and most typical way to determine surface tension among several methods of surface tension measurements. We demonstrated a hybrid force measurement system to obtain the capillary force directly so that we could investigate surface tension in nanoscale.
The hybrid system of a quartz tuning fork (QTF)-based, amplitude modulation atomic force microscope (AM-AFM) and a microelectromechanical system (MEMS) measures simultaneously the dynamic and static forces for nanoconfined water bridge formed between hydrophilic surfaces. This system formed a stable water bridge at a certain distance and obtained the absolute capillary force besides dynamic properties of the water meniscus. Moreover, the
MEMS force sensor provides the additional force information, verifies the AFM measurement, allows accessibility of multiple driving frequencies, and expresses the stress or strain of the confined nanoscale water column. Stress and strain measurements revealed that the nanoconfined water meniscus has the Young's modulus comparable to that of soft rubber or soft tissues and the low loss tangent value close to the solid-like behavior.
We calculated the capillary force on the basis of Young-Laplace equation and compared the analyzed values with the experimental findings. This numerical evaluation of Young-Laplace equation enables the surface tension in nanoscale to be investigated closely. Therefore, we found that the surface tension value of water meniscus in nanoscale significantly decreases less than 20 % of the one in bulk water. This observations may resolve the existing discrepancies between experiments and theories associated with liquid-vapor transition effects in nanoconfined water and allow a contribution to the applications such as self-assembly of bio-molecules and efficient design of nanomaterials.
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dc.description.tableofcontentsChapter 1 Introduction
Chapter 2 Hybrid MEMS-AFM system
2.1 Quartz tunning fork (QTF)-based Atomic force microscopy (AFM)
2.2 Microelectromachanical system (MEMS) force sensor
2.2.1 Surface micro-machining of z-axis force sensor
2.2.2 Shear MEMS device works along x- and y-axes
2.2.3 MEMS in hybrid system
2.3 Hybrid MEMS-AFM system
Chapter 3 Dynamic and Static force measurement using Hybrid
MEMS-AFM
3.1 Introduction
3.2 Dynamic and Static force measurement
3.3 Capillary force of nanoscale water cluster
3.4 Viscoelasticity of nanoscale water cluster
3.5 Conclusion
Chapter 4 Investigation on surface tension of nanoscale water
4.1 Introduction
4.2 Method and modeling of capillary force
4.2.1 Modeling for measured force using capillary force
4.2.2 Solution of Young-Laplace equation
4.2.3 Comparison between experimental results and theoretical calculations
4.2.4 Theoretic analysis and numerical simulation
4.2.5 Fitting Method using Young-Laplace equation
4.3 Investigation of surface tension in nanoscale
4.4 Conclusion
Chapter 5 Conclusions
Appendix A Nano-bubble formation and surface tension
A.1 The predicted surface tension by nucleation theory
A.2 The cluster model for bubble formation
Appendix B Numerical calculation of capillary force in water nanomeniscus
Appendix C Fabricated tips for hybrid MEMS-AFM system
C.1 Quartz tip fabricated by a laser puller
C.2 The size control capability
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dc.format.extent88-
dc.language.isoeng-
dc.publisher서울대학교 대학원-
dc.subjectNanoscale water, Surface tension, Capillary force, MEMS, AFM-
dc.subject.ddc523-
dc.titleInvestigation on surface tension of nanoscale water-
dc.title.alternative나노스케일 물의 표면장력 연구-
dc.typeThesis-
dc.typeDissertation-
dc.contributor.AlternativeAuthorSoyoung Kwon-
dc.contributor.department자연과학대학 물리·천문학부-
dc.description.degreeDoctor-
dc.date.awarded2015-08-
dc.contributor.major응집물질물리-
dc.identifier.holdings000000000023▲000000000025▲000000056910▲-
Appears in Collections:
College of Natural Sciences (자연과학대학)Dept. of Physics and Astronomy (물리·천문학부)Physics (물리학전공)Theses (Ph.D. / Sc.D._물리학전공)
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