Study on the conformation and dynamics of amphoteric polymers and the theoretical hydration of alanine dipeptide = 양쪽성 고분자의 형태와 동력학 및 알라닌 디펩티드의 이론적 수화에 관한 연구

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Part A The effects of the structural variation and the relative stability by the hydration of Alanine dipeptide in $C_7^eq$, $C_7^ax$, $C_5$, $α_R$, and $P_Ⅱ$ conformations were investigated by the method of SUMSL(Secant-type Unconstrained Minimization Solver) energy minimization technique with the empirical potential energy function of the solute, and ST2 water model. The binding sites of water molecules in the solute were selected from spherical interaction energy maps. As a function of the number of added water molecules, we traced the structural variations mainly in the (φ, ψ) torsion angle space, and calculated the total internal energies of each solute-water systems to evaluate the relative probabilities between those five conformers. The results indicate that the conformers having no intramolecular hydrogen-bondings, such as $α_R$, $C_5$, and $P_Ⅱ$, show larger structural variations than the conformers of $C_7^ax$, and $C_7^eq$ that have intramolecular hydrogen-bondings. The torsion angle of ψ fluctuated more than φ for all the examined conformers. The energetically dominant conformation is shifted from $C_7^eq$to (R as the hydration is preceded. Part B Solution conformations and dynamic mobilities of novel amphoteric copolymers were studied for aqueous solutions of P(sodium 2-methacryloyloxyethanesulfonate-co-2-methacryloyloxyethyltrimethyl- ammonium iodide) [P(NaMES-co-METMAI)] as a function of composition, concentration, addition of HCl and addition of KCl. As HCl or KCl was added successively to the 5 w/v% copolymer solutions, the reduced viscosities of the solutions were reduced except the 1:1 copolymer solution. The dynamic mobility of the cationic side chain was estimated with the quadrupolar $^14N$-NMR relaxation technique. The motion of the interacting counterion, $Na^+$, was studied by Poisson- Boltzmann electrostatic theories and the quadrupolar $^23Na$-NMR. Since the intramolecular 1:1 ion pair between MES- and $METMA^+$ acts as an effective ...
Advisors
Jhon, Mu-Shik전무식
Description
한국과학기술원 : 화학과,
Publisher
한국과학기술원
Issue Date
1995
Identifier
101851/325007 / 000895273
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학과, 1995.8, [ ix, 77 p. ]

Keywords

Theoretical Hydration; Polyelectrolyte; NMR; Amphoteric Copolymer; Conformation; 형태; 이론적 수화; 전해질 고분자; 핵자기공명법; 양쪽성 공중합체

URI
http://hdl.handle.net/10203/31419
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=101851&flag=dissertation
Appears in Collection
CH-Theses_Ph.D.(박사논문)
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