학술논문
Development of Functionalized Terthiophene-based Conducting Polymer and Microfluidic Channel Devices for Electroanalytical Applications / 전기분석화학의 응용을 위한 기능성 고분자 및 마이크로 플루이딕 디바이스의 개발
Document Type
Dissertation/ Thesis
Author
Source
Subject
Language
English
Abstract
본 학위논문은 전기 분석/전기분석화학의 응용을 위한 기능성 작용기를 갖는 터싸이오펜 기반의 전도성 고분자 및 마이크로 플루이딕 디바이스의 개발에 대한 연구결과를 나타내었다. 현재까지 다양한 종류의 전도성 고분자가 개발되어 전기변색 디스플레이와 소자, 전기화학 센서 (바이오센서, 케미컬센서), 전지 (2차전지, 연료전지, 생체연료전지), 유기전자 및 유기발광 다이오드(OLED) 분야 등 다양한 응용분야에 사용되고 있다. 전도성 고분자는 저비용의 우수한 전기적, 광학적, 전도성 특성을 갖고 있으며, 간단히 가공할 수 있고 내식성 또한 뛰어난 소재이며, 최근 전도성 기능성 작용기를 포함하는 전기전도성 고분자의 대한 관심이 높아지고 있다. 이러한 작용기의 도입은 단량체와 고분자의 특성을 미세하게 조절을 할 수 있으며, 이를 이용하여 전기화학 센서나 연료전지를 제조하기 위한 기능성 물질이나 생체분자의 고정점을 제공할 수 있기 때문이다. 따라서 다양한 소자 및 디바이스를 생산하기 위해서는 전도성 고분자를 포함하는 다양한 관능기의 개발이 필요하다. 최근에는 유/무기 분석물, 다양한 생물학적 분자 및 세포를 분리 및 검출하기 위한 미세유체 채널 장치가 개발되었으며, 이는 적은 양의 시료를 쉽게 간단하게 검출할 수 있는 뛰어난 능을 가지고 있기 때문이다. 하지만, 이러한 기술은 종종 시간이 많이 걸리는 단계, 복잡한 준비/설계 및 열악한 분리 분해능의 문제가 있다. 따라서 이러한 문제를 극복하기 위해서는 간단하고 안정적인 미세유체 채널이 필요하다. 이러한 목적으로 본 학위논문에서는 다양한 기능성 작용기를 갖는 전기전도성의 개발과 이를 활용한 전기변색소자, 태양전지, 생체연료전지 및 화학센서로의 응용 연구를 수행하였으며, 마이크로 플루이딕스 기술을 접목하여 생체연료전지와 화학센서로의 응용 연구를 수행하였다.1장에서는 전기전도성 고분자와 마이크로 플루이딕스 및 각각의 응용분야에 대한 대한 전반적인 이해를 위하여 관련된 지식들을 정리하였다.2장에서는 기능성 작용기인 아민기과 카복실기에 초점을 맞추어 아민기, 카복실기, 아민과 카복실기를 동시에 갖는 전기전도성 단량체(3-([2,2':5',2''-terthiophen]-3'-yl)-5-aminobenzoicacid, TABA)를 합성하여 특성연구 한 이후 전기변색 소자로의 응용연구를 수행하였다. 카복실기가 결합된 단량체(TBA)는 electron acceptor의 특성을 보였고, 아민기가 결합된 단량체(PAT)는 electron donor 특성을 보였으며 이 둘을 포함하는 단량체(TABA)는 중간단계의 특성을 보였다. 이들을 고분자로 만들어 전도도를 측정한 결과 0.11 S/cm(단일 도너 그룹 포함)에서 0.24 S/cm(단일 억셉터 그룹 포함), 0.19 S/cm(도너 및 억셉터 그룹 모두)로 증가하였다. pTABA는 470nm(+1.07/+0.80V)에서 뉴트랄, 781nm(+1.07/+0.80V)에서 폴라론, 950nm(+ 1.30/+1.19V)에서 바이폴라론을 보였다. pTABA는 pTBA나 pPAT가 2~3가지의 색을 보인것에 비하여 9종의 색변화를 보였다.3장에서는 p-(3'(benzoic acid) -2,2':5',2'- terthiophene) (pTTBA)와 azulene(Azu) 의 공중합체를 활용하여 낮은 전위에서 다양한 색을 구현하는 변색소자를 제작하였다. 전도성 고분자는 0.1M TBAP/acetonitrile 전해질 조건에서Pt 전극 위에 형성하였다. 공중합을 위한 각각의 고분자의 산화/환원 피크는 Epa/Epc = +0.98/+0.84 V(pTBA), +0.59/+0.42 V(Azu)에서 관찰되었다. 공중합체는 두 개의 산화/환원 피크가 보였으며 +0.61/+0.50 및 +0.98/+0.89 V이는 각각의 고분자에서 기인한 것으로 판단한다. 전도성 고분자의 전기화학적 및 분광화학적 특성을 확인하기 위해 in situ spectroelectrochemical 기법으로 백금 전극에서 전기화학적 성장 및 고분자를 연구하였다. 공중합체의 전기 변색 성능은 단일 고분자에 비해 최소 구동전압은 0.3V였으며, 1.4V 까지 다양한 색상 변화를 보였다. 4장에서는, 세 가지 새로운 terthiophene 아크릴산 유도체, 3-(4-([2,2':5',2''-terthiophen]-3'-yl)phenyl)acrylic acid (TPAA), 3-(5'-(thiophen-2-yl)-[2,2':3',2''-terthiophen]-5''-yl)acrylic acid (TTAA) 및 3-(5-([2,2':5',2''-terthiophen]-3'-yl)furan-2-yl)acrylic acid (TFAA)을 합성하고 FT-IR, 1H및 13C-NMR, 질량 분광기로 확인하였다. 단량체의 분광학적 특성은 TPAA(UV-Vis: 310nm, PL: 529nm), TTAA(UV-Vis: 337nm, PL: 535nm), TFAA(UV-Vis: 337nm, PL: 508nm)이다. 전기화학적으로 제조된 고분자는 순환 전압전류법, in situ 전도도, in situ UV-Vis 분광법 및 AFM 기술로 특성 연구를 수행하였다. 1.4 V에서 각 고분자에 대한 in situ 전도도는 pTPAA(0.23 S/cm), pTTAA(0.22 S/cm), pTFAA(0.17 S/cm)로 나타났다. 전도성 메커니즘 확인을 위하여 DCVA 방법을 활용하여 계산한 결과, 고분자에 대한 라디칼 종 을 확인할 수 있었다. 최종적으로는 연료감응 태양전지를 만들어 효율을 측정하였으며, AM 2.5 조건에서 활성층 면적이 0.24 cm2일 , pTPAA 기반의 염료태양전지는 2.34%의 에너지 변환효율을 달성하였다. (N3 염료는 본 연구실에서 5.18%였음) 5장에서는 포도당 검출을 위한 전기 변색 장치와 결합된 일회용 미세유체 바이오 연료 전지(MBC) 장치를 제작하였다. 양극과 음극 AuNi 덴드라이트 표면에 기능성 작용기를 갖는 전도성 고분자를 형성한 이후, 양극의 경우 GOx, 음극의 경우 Laccase을 고정하여 생체연료전지를 형성하였다. Viologen기반의 전기변색 소자를 제작한 이후, 이를 생체연료전지와 연결하여 포도당 농도 0 ~ 10 mM 범위에서 변색법을 활용하여 검출이 가능하였다. 6장에서는 미세유체 채널 벽에 대칭적으로 적용된 작은 교류(AC) 필드로 전기역학적 힘에 의해 분리된 중금속 이온(HMI)을 검출하기 위한 일회용 전기역학적 미세유체 센서를 개발에 대하여 연구하였다. 중금속 검출을 위한 센서부에 대한 최적화 연구를 수행하였으며, 채널의 뚜껑의 친수성도를 조절하여 유체의 흐름이 가능한 채널 센서를 제작하였다. 흐름부에서는 다양한 종류의 중금속 이온을 분리하기 위한 교류전위가 인가되었으며, 중금속들에 대한 분리 검출이 가능한 실험 조건도 최적화 할 수 있었다. 분리검출법에 대한 선형 검출 범위는 0.1 ~ 200.0 ppb이고, 검출한계는 0.04 ± 0.023 (Cu2+), , 0.29 ± 0.05 (Cd2+), 0.07 ± 0.011 (Hg 2+), 0.14 ± 0.06 ppb (Pb 2+)으로 확인 되었다. 이는 실제 물 시료에서 ICP-MS를 측정한 결과와 일치하였다.
This thesis focused on the development of functionalized conducting polymer and microfluidic channel devices for the applications of electroanalytical purposes. To date, various kinds of conducting polymers have been developed and used for various applications in the fields of electrochromic display/devices, electrochemical sensors, batteries, organic electronics, and organic light-emitting diode (OLED), due to their potential applicability, such as low cost, electrical, optical, and conducting characteristics, processability, and corrosion resistance. In addition, attention to a functional group containing conducting polymer is increased recently because these functional groups can control the fine-tuning of the monomer and polymer properties and provide the anchoring points for functional materials or biomolecules to prepare the electrochemical sensor or fuel cells. So, developing various functional groups containing conducting polymer is necessary to produce various devices. Lately, microfluidic channel devices have been developed to attempt to separate and detect organic/inorganic analytes, different biological molecules, and cells due to their excellent separation capability, easily manipulated experimental parameters, and precise control of the small volume of samples. However, these techniques frequently involve time-consuming steps, complicated preparation/design, and poor separation resolution. To overcome these problem, a simple and reliable microfluidic channel is required. In this thesis, functionalized terthiophene-based conducting polymer with a functional group (amine, carboxylic acid, and acrylic acid) is introduced to the development of various electrochemical applications, such as electrochromic devices, solar cells, and biofuel cells. Moreover, simply prepared microfluidic channel devices are presented to develop portable electrochemical sensors as well as biofuel cells. Chapter 1 introduces general information on conducting polymer and microfluidic channel devices, such as brief history, preparation, and application. In chapter 2, A monomer precursor of polyterthiophene derivative bearing both electron donor (-NH2) and acceptor (-COOH) groups (3-([2,2':5',2''-terthiophen]-3'-yl)-5-aminobenzoicacid, TABA) was newly synthesized and characterized. The comparison analysis was performed for pTABA with a single acceptor or donor group-bearing polymer. The electrical study confirmed that the conductivity of the functionalized polymer increased from 0.11 S/cm (with single donor group) to 0.24 S/cm (with single acceptor group) through 0.19 S/cm (for both donor and acceptor groups), as a result of stabilization of quinoid form on the polymer backbone. Derivative cyclic voltabsorptometry (DCVA) obtained for pTABA confirmed the formation of neutral, polaron, and bipolaron at 470 nm (at +1.07/+0.80 V), 781 nm (at +1.07/+0.80 V), and 950 nm (at +1.30/+1.19 V), respectively. The electrochromic performance of polymer bearing both donor and acceptor groups achieved nine colors between orange (0.0 V) and midnightblue (1.4 V) compared with that of single functional groups displaying two or three colors. In chapter 3, Electrochromic properties of p-(3′(benzoic acid) −2,2′:5′,2′- terthiophene) (pTTBA), azulene (Azu) and the copolymer of pTTBA and azulene were compared to achieve multichromatic properties in low potential. The polymer was formed onto the Pt electrode by a potential cyclic method in 0.1 M TBAP/Acetonitrile. The redox peaks of polymers were observed at Epa/Epc = +0.98/+0.84 V (pTTBA), +0.59/+0.42 V (Azu). Besides, the copolymer shows two redox peaks during charging/discharging in the blank electrolyte solution at +0.61/+0.50 and +0.98/+0.89 V corresponding to the pAzu and pTTBA. Electrochemical growth and polymer were studied at platinum electrodes by in situ spectroelectrochemical techniques to confirm the electrochemical and spectrochemical properties of conducting polymer. The copolymer's electrochromic performance achieved various color changes between 0.0 V to 1.4 V compared with that of single functional groups displaying two or three colors. In chapter 4, three new terthiophene acrylic acids derivatives, 3-(4-([2,2':5',2''-terthiophen]-3'-yl)phenyl)acrylic acid (TPAA), 3-(5'-(thiophen-2-yl)-[2,2':3',2''-terthiophen]-5''-yl)acrylic acid (TTAA) and 3-(5-([2,2':5',2''-terthiophen]-3'-yl)furan-2-yl)acrylic acid (TFAA) were synthesized and confirmed by FT-IR, 1H and 13C NMR, mass spectroscopy. UV–visible absorption and PL emission bands of each monomer were observed TPAA (UV-Vis: 310 nm, PL: 529 nm), TTAA (UV-Vis: 337 nm, PL: 535 nm), and TFAA (UV-Vis: 337 nm, PL: 508 nm), respectively. Electrochemically prepared polymers were studied by cyclic voltammetry, in situ conductivity, in situ UV-Vis spectroscopy, and AFM techniques; The conductivity of pTPAA (0.23 S/cm), pTTAA (0.22 S/cm), pTFAA (0.17 S/cm) at 1.4 V. Spectroelectrochemical analyses were performed to observe the radical species generation onto the polymer during the conducting process and DCVA techniques analyzed these species. Finally, a photovoltaic cell is assembled with a newly prepared conducting polymer on the TiO2 for photo-anode and Pt-counter electrode as a cathode with I−/I3− as a redox couple containing propionitrile solution as an electrolyte. The higher energy conversion efficiency was achieved with the pTPAA-based dye solar cell for 2.34%. (active layer = 0.24 cm2).In chapter 5, we presented a disposable microfluidic biofuel cell (MBC) device coupled with an electrochromic device for glucose detection. Both anode and cathode were prepared by redox enzyme(glucose oxidase for anode, Laccase for cathode) immobilized with functionalized conducting polymer onto the AuNi dendrite surface. The conducting polymer-based microfluidic channel electrodes revealed well-defined electron transfer processes. The cell was operated with a 10.0 mM glucose solution, generated a maximum electrical power density of 340 μW/cm2, and an open-circuit voltage of 0.56 V. Electrochromic display was prepared by electrochromic viologen molecule in ITO glass electrochromic cell to display the glucose level by color change. The performances of microfluidic biofuel cells were tested in a standard glucose solution, and it showed various color changes in the range of 0 to 10 mM glucose concentration. In chapter 6, electrodynamic force applied microfluidic sensor device was developed to detect heavy metal ions (HMIs). This sensor device can deliver the sample solution by capillary force coupled with electrodynamic force resulting in a flow rate change. To control the flow rate, we optimized different kinds of plastic lids on the channel wall for changing the hydrophilicity as well as different alternating current (AC) conditions, such as frequency and voltage. During the sample solution pass through the separation channel, the target HMIs were separated. The detection electrode built in the channel sensor was immobilized by a nano complex formed by amine-functionalized poly-3',4'-diamino-2,2'; 5'2''-terthiophene (pDATT) with graphene oxide to shows the best detection performance. Finally, this sensor device was optimized to detect the HMIs in the real sample then compared with the conventional ICP-MS.
This thesis focused on the development of functionalized conducting polymer and microfluidic channel devices for the applications of electroanalytical purposes. To date, various kinds of conducting polymers have been developed and used for various applications in the fields of electrochromic display/devices, electrochemical sensors, batteries, organic electronics, and organic light-emitting diode (OLED), due to their potential applicability, such as low cost, electrical, optical, and conducting characteristics, processability, and corrosion resistance. In addition, attention to a functional group containing conducting polymer is increased recently because these functional groups can control the fine-tuning of the monomer and polymer properties and provide the anchoring points for functional materials or biomolecules to prepare the electrochemical sensor or fuel cells. So, developing various functional groups containing conducting polymer is necessary to produce various devices. Lately, microfluidic channel devices have been developed to attempt to separate and detect organic/inorganic analytes, different biological molecules, and cells due to their excellent separation capability, easily manipulated experimental parameters, and precise control of the small volume of samples. However, these techniques frequently involve time-consuming steps, complicated preparation/design, and poor separation resolution. To overcome these problem, a simple and reliable microfluidic channel is required. In this thesis, functionalized terthiophene-based conducting polymer with a functional group (amine, carboxylic acid, and acrylic acid) is introduced to the development of various electrochemical applications, such as electrochromic devices, solar cells, and biofuel cells. Moreover, simply prepared microfluidic channel devices are presented to develop portable electrochemical sensors as well as biofuel cells. Chapter 1 introduces general information on conducting polymer and microfluidic channel devices, such as brief history, preparation, and application. In chapter 2, A monomer precursor of polyterthiophene derivative bearing both electron donor (-NH2) and acceptor (-COOH) groups (3-([2,2':5',2''-terthiophen]-3'-yl)-5-aminobenzoicacid, TABA) was newly synthesized and characterized. The comparison analysis was performed for pTABA with a single acceptor or donor group-bearing polymer. The electrical study confirmed that the conductivity of the functionalized polymer increased from 0.11 S/cm (with single donor group) to 0.24 S/cm (with single acceptor group) through 0.19 S/cm (for both donor and acceptor groups), as a result of stabilization of quinoid form on the polymer backbone. Derivative cyclic voltabsorptometry (DCVA) obtained for pTABA confirmed the formation of neutral, polaron, and bipolaron at 470 nm (at +1.07/+0.80 V), 781 nm (at +1.07/+0.80 V), and 950 nm (at +1.30/+1.19 V), respectively. The electrochromic performance of polymer bearing both donor and acceptor groups achieved nine colors between orange (0.0 V) and midnightblue (1.4 V) compared with that of single functional groups displaying two or three colors. In chapter 3, Electrochromic properties of p-(3′(benzoic acid) −2,2′:5′,2′- terthiophene) (pTTBA), azulene (Azu) and the copolymer of pTTBA and azulene were compared to achieve multichromatic properties in low potential. The polymer was formed onto the Pt electrode by a potential cyclic method in 0.1 M TBAP/Acetonitrile. The redox peaks of polymers were observed at Epa/Epc = +0.98/+0.84 V (pTTBA), +0.59/+0.42 V (Azu). Besides, the copolymer shows two redox peaks during charging/discharging in the blank electrolyte solution at +0.61/+0.50 and +0.98/+0.89 V corresponding to the pAzu and pTTBA. Electrochemical growth and polymer were studied at platinum electrodes by in situ spectroelectrochemical techniques to confirm the electrochemical and spectrochemical properties of conducting polymer. The copolymer's electrochromic performance achieved various color changes between 0.0 V to 1.4 V compared with that of single functional groups displaying two or three colors. In chapter 4, three new terthiophene acrylic acids derivatives, 3-(4-([2,2':5',2''-terthiophen]-3'-yl)phenyl)acrylic acid (TPAA), 3-(5'-(thiophen-2-yl)-[2,2':3',2''-terthiophen]-5''-yl)acrylic acid (TTAA) and 3-(5-([2,2':5',2''-terthiophen]-3'-yl)furan-2-yl)acrylic acid (TFAA) were synthesized and confirmed by FT-IR, 1H and 13C NMR, mass spectroscopy. UV–visible absorption and PL emission bands of each monomer were observed TPAA (UV-Vis: 310 nm, PL: 529 nm), TTAA (UV-Vis: 337 nm, PL: 535 nm), and TFAA (UV-Vis: 337 nm, PL: 508 nm), respectively. Electrochemically prepared polymers were studied by cyclic voltammetry, in situ conductivity, in situ UV-Vis spectroscopy, and AFM techniques; The conductivity of pTPAA (0.23 S/cm), pTTAA (0.22 S/cm), pTFAA (0.17 S/cm) at 1.4 V. Spectroelectrochemical analyses were performed to observe the radical species generation onto the polymer during the conducting process and DCVA techniques analyzed these species. Finally, a photovoltaic cell is assembled with a newly prepared conducting polymer on the TiO2 for photo-anode and Pt-counter electrode as a cathode with I−/I3− as a redox couple containing propionitrile solution as an electrolyte. The higher energy conversion efficiency was achieved with the pTPAA-based dye solar cell for 2.34%. (active layer = 0.24 cm2).In chapter 5, we presented a disposable microfluidic biofuel cell (MBC) device coupled with an electrochromic device for glucose detection. Both anode and cathode were prepared by redox enzyme(glucose oxidase for anode, Laccase for cathode) immobilized with functionalized conducting polymer onto the AuNi dendrite surface. The conducting polymer-based microfluidic channel electrodes revealed well-defined electron transfer processes. The cell was operated with a 10.0 mM glucose solution, generated a maximum electrical power density of 340 μW/cm2, and an open-circuit voltage of 0.56 V. Electrochromic display was prepared by electrochromic viologen molecule in ITO glass electrochromic cell to display the glucose level by color change. The performances of microfluidic biofuel cells were tested in a standard glucose solution, and it showed various color changes in the range of 0 to 10 mM glucose concentration. In chapter 6, electrodynamic force applied microfluidic sensor device was developed to detect heavy metal ions (HMIs). This sensor device can deliver the sample solution by capillary force coupled with electrodynamic force resulting in a flow rate change. To control the flow rate, we optimized different kinds of plastic lids on the channel wall for changing the hydrophilicity as well as different alternating current (AC) conditions, such as frequency and voltage. During the sample solution pass through the separation channel, the target HMIs were separated. The detection electrode built in the channel sensor was immobilized by a nano complex formed by amine-functionalized poly-3',4'-diamino-2,2'; 5'2''-terthiophene (pDATT) with graphene oxide to shows the best detection performance. Finally, this sensor device was optimized to detect the HMIs in the real sample then compared with the conventional ICP-MS.