Depletion-induced crystallization of colloidal particles and regioselective crystal deposition고갈력 기반의 콜로이드 결정화 및 패턴화

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Colloids, which spontaneously form crystal structures, have been widely studied as “visible atomic crystallization models” because they are large enough to be observed using microscopes and still small enough to be affected by thermal energy. In particular, colloidal crystallization is a significant research field since its mechanisms rely on thermodynamic and kinetic features of the particles, and thus it is possible to grasp and control the morphology and properties of crystals by analyzing those features. In order to model the crystallization of atoms from that of colloids, most of the previous studies adopted hard spheres, in which only the short-range repulsive interaction works, to calculate interparticle potentials. However, the interaction potential of atoms usually represented by Lennard-Jones potential is different from that of hard spheres due to the attractive long-range interactions acting among the actual atoms. Therefore, a more rational approach would be to establish a crystallization model employing the potentials between colloids corresponding to the interactions of atoms. In this thesis, an attraction-induced colloidal crystallization is demonstrated and investigated analytically as well as a phase transition behavior. For this purpose, depletion force is introduced as the attractive force using depletants, and then the attraction and repulsion between negatively charged polystyrene nanoparticles are controlled experimentally. It is figured out that this colloidal system has reached four distinct phases depending on the composition. Also, the thermodynamic and kinetic conditions under which phase transition occurs are established from the analysis of interaction potentials between colloids. Furthermore, an additional study is conducted to demonstrate the patterning of crystals not previously reported by applying the intrinsic feature of depletion force that their intensity is proportional to the overlap of excluded volumes.
Advisors
Kim, Shin-Hyunresearcher김신현researcher
Description
한국과학기술원 :생명화학공학과,
Publisher
한국과학기술원
Issue Date
2020
Identifier
325007
Language
eng
Description

학위논문(석사) - 한국과학기술원 : 생명화학공학과, 2020.2,[iv, 58 p. :]

Keywords

colloids▼aatomic model▼adepletion forces▼apair-potential▼aself-assembly▼aphotonic crystals▼apatterning; 콜로이드▼a원자 모델▼a고갈력▼a입자 간 퍼텐셜▼a자가조립▼a광결정▼a패턴화

URI
http://hdl.handle.net/10203/284046
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=910841&flag=dissertation
Appears in Collection
CBE-Theses_Master(석사논문)
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