#### Study of surface waves at the air-water interface covered by a monolayer = 공기-물 계면에서 단분자층의 표면파에 대한 연구

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We have studied the domain structures and the viscoelastic properties of charged lipid monolayers at the air-water interface with an adsorbed polyelectrolytes. Coupling of flexible (PAAS:polyacrylic acid sodium salt) and semiflexible ($\lambda$ DNA) polyelectrolytes onto an oppositely charged lipid monolayer (DOTAP:dioleoyl trimethylammonium propane chloride) at the air-liquid interface leads distinctive collapse behavior with lateral compression. In both cases, trilayer domains form by nucleation growth mechanism followed by multilayer formation with further compression. The flexible chain induces circular, fluid domains while the semiflexible chain induces elongated, solid-like domains. These morphological differences show that the flexibility of adsorbed polymers strongly affects the rigidity of the lipid membrane. Next, we focused on the effects of the chain length. We have obtained informations about domain structure, comprssibility, dilational and shear surface viscosities. Within a low frequency range $(200Hz \sim 400Hz)$,using externally exited surface wave spectroscopy, the change of chain length of PSS(poly styrene sulfonic acid with sodium salt) in the subphase affects damping constant in surface wave. However at high frequency $(2kHz \sim 7kHz)$,using heterodyne surface wave spectroscopy, this tendency is dissapeared. Kramers dispersion relation which is good agreement with low molecular weight surfactant molecules can not explain our data. In this picture, we obtained negative dilational viscosities. But Hardens general dispersion relation for viscoelastic polymer film can explain. This means that the surface waves are highly affected by adsorbed polymer.
Kim, Mahn-Wonresearcher김만원researcher
Description
한국과학기술원 : 물리학과,
Publisher
한국과학기술원
Issue Date
2009
Identifier
309020/325007  / 020035191
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 물리학과, 2009.2, [ vi, 48 p. ]

Keywords

soft matter; surface wave; monolayer; polyelectrolyte; air-water interface; 연성물질; 표면파; 단분자막; 전해고분자; 공기-물 계면

URI
http://hdl.handle.net/10203/47603