Study on the various surface modifications based on self-assembled monolayer and their applications자기조립 단분자막 형성에 기초한 다양한 표면 개질과 그 응용에 관한 연구

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We report the deposition of gold nanoparticles into arrays of surface nanopores obtained from hexagonally ordered polystyrene-block-poly(4-(tert-butyldimethylsilyl)oxystyrene) (PS-b-PSSi) diblock copolymer films on gold substrate. The deposition occurs spontaneously from aqueous solution and is driven by either electrostatic interactions between the nanoparicles and the surfaces. To this spontaneous deposition, Nanoporous $SiO_2$ Patterned substratae was chemically modified with either positively charged amino SAMs or inert methyl SAMs. The deposition of gold nanoparicles was characterized by atomic force microscopy (AFM). We have observed preferential immobilization of individual nanoparicles onto the amine modified surfaces. The inclusion density and selectivity of nanoparticles deposition onto the surface was found to depend predominantly on the methods through which the nanoporous surfaces were prepared and chemically functionalized. Organic conductive polymers (CPs) are promising candidates for next-generation thermoelectric (TE) materials due to their light weight, simple processability, and environment-friendly characteristics. Moreover, their low thermal conductivity provides an effective strategy to improve TE performance. Among numerous CPs, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT/PSS) is one of the promising candidates for TE materials due to its advantages of high electrical conductivity, low thermal conductivity, light weight, and high flexibility. Nevertheless, CPs-based TE materials are still considered to be deficient due to their lower Seebeck coefficient compared to inorganic TE materials. First, we demonstrate that the TE performance of PEDOT/PSS films can be improved by using self-assembled monolayers (SAMs) of a NH2-terminated silane, APTMS. APTMS can not only control the hole carrier concentration to enhance the Seebeck coefficient, but it can also rearrange the orientation of PEDOT chains to improve the charge transport pathways. The highest power factor of PEDOT/PSS films with APTMS SAMs reaches about $86.6 \muW m-1K-2$, which is a threefold enhancement compared to that of a pristine PEDOT/PSS film without SAMs. This work provides a new procedure to control the Seebeck coefficient and reorientation of PEDOT chains by using the amine-terminated SAMs. Furthermore, we expect that this procedure can contribute to the fabrication of organic-based, highly flexible, high-performance TE device modules. Secondly, we propose a simple method to enhance the TE performance of PEDOT/PSS films by coating on self-assembled monolayers (SAMs) with NH2-terminated silanes, APTMS. The NH2 groups of SAMs can control the carrier concentration by capturing holes in PEDOT chains with the lone pair electrons of the amine groups. Moreover, in order to maximize the effects of SAMs on the TE performance, the thicknesses of PEDOT/PSS films were successfully controlled by simple blending ethanol to PEDOT/PSS solution. Through the thickness optimization, the power factor of PEDOT/PSS films with SAMs increased threefold than that of pristine PEDOT/PSS film without SAMs. We also fabricated a flexible TE device module consisting of PEDOT/PSS legs on the ATPMS-treated flexible substrate and investigated its feasibility for practical application.
Advisors
Kim, Jin Baekresearcher김진백researcher
Description
한국과학기술원 :화학과,
Publisher
한국과학기술원
Issue Date
2016
Identifier
325007
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학과, 2016.8,[x, 78 p. :]

Keywords

Block copolymer; self-assembled monolayer▼athermoelectric▼ananoparticle patterning▼aPEDOT/PSS▼aseebeck coefficient; 블록공중합체▼a자기조립 단분자막▼a열전▼a나노입자 패터닝▼aPEDOT/PSS

URI
http://hdl.handle.net/10203/265453
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=849853&flag=dissertation
Appears in Collection
CH-Theses_Ph.D.(박사논문)
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