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Ahn Y, Kang Y, Kye H, Kim MS, Lee WH, Kim BG. Exploring Pore Formation and Gas Sensing Kinetics Using Conjugated Polymer-Small Molecule Blends. ACS APPLIED MATERIALS & INTERFACES 2024; 16:31719-31728. [PMID: 38836704 DOI: 10.1021/acsami.4c03107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
Controlling miscibility between mixture components helps induce spontaneous phase separation into distinct domain sizes, thereby resulting in porous conjugated polymer (CP) films with different pore sizes after selective removal of auxiliary components. The miscibility of the CP mixture can be tailored by blending auxiliary model components designed by reflecting the difference in solubility parameters with the CP. The pore size increases as the difference in solubility parameters between the matrix CP and auxiliary component increases. Electrical properties are not critically damaged even after forming pores in the CP; however, excessive pore formation enables pores to spread to the vicinity of the dielectric layer of CP-based field-effect transistors (FETs), leading to partial loss of the carrier-transporting active channel in the FET. The porous structure is advantageous for not only increasing detection sensitivity but also improving the detection speed when porous CP films are applied to FET-based gas sensors for NO2 detection. The quantitative analysis of the response-recovery trend of the FET sensor using the Langmuir isotherm suggests that the response speed can be improved by more than 2.5 times with a 50-fold increase in NO2 sensitivity compared with pristine CP, which has no pores.
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Affiliation(s)
- Yejin Ahn
- Department of Organic and Nano System Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Yeongkwon Kang
- Department of Organic and Nano System Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Hyojin Kye
- Department of Organic and Nano System Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Min Seon Kim
- Department of Organic and Nano System Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Wi Hyoung Lee
- Department of Organic and Nano System Engineering, Konkuk University, Seoul 05029, Republic of Korea
- Division of Chemical Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Bong-Gi Kim
- Department of Organic and Nano System Engineering, Konkuk University, Seoul 05029, Republic of Korea
- Division of Chemical Engineering, Konkuk University, Seoul 05029, Republic of Korea
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Jeong H, Gu J, Mwasame P, Patankar K, Yu D, Sing CE. Modeling the competition between phase separation and polymerization under explicit polydispersity. SOFT MATTER 2024; 20:681-692. [PMID: 38164983 DOI: 10.1039/d3sm01411h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
The dynamics of phase separation for polymer blends is important in determining the final morphology and properties of polymer materials; in practical applications, this phase separation can be controlled by coupling to polymerization reaction kinetics via a process called 'polymerization-induced phase separation'. We develop a phase-field model for a polymer melt blend using a polymerizing Cahn-Hilliard (pCH) formalism to understand the fundamental processes underlying phase separation behavior of a mixture of two species independently undergoing linear step-growth polymerization. In our method, we explicitly model polydispersity in these systems to consider different molecular-weight components that will diffuse at different rates. We first show that this pCH model predicts results consistent with the Carothers predictions for step-growth polymerization kinetics, the Flory-Huggins theory of polymer mixing, and the classical predictions of spinodal decomposition in symmetric polymer blends. The model is then used to characterize (i) the competition between phase separation dynamics and polymerization kinetics, and (ii) the effect of unequal reaction rates between species. For large incompatibility between the species (i.e. high χ), our pCH model demonstrates that the strength for phase separation directly corresponds to the kinetics of phase separation. We find that increasing the reaction rate k̃, first induces faster phase separation but this trend reverses as we further increase k̃ due to the competition between molecular diffusion and polymerization. In this case, phase separation is delayed for faster polymerization rates due to the rapid accumulation of slow-moving, high molecular weight components.
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Affiliation(s)
- Hyeonmin Jeong
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.
| | - Junsi Gu
- Dow Chemical Company, Midland, MI, 48667, USA
| | | | | | - Decai Yu
- Dow Chemical Company, Midland, MI, 48667, USA
| | - Charles E Sing
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.
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Leguizamon SC, Ahn J, Lee S, Jones BH. Tuneable phase behaviour and glass transition via polymerization-induced phase separation in crosslinked step-growth polymers. SOFT MATTER 2022; 18:4455-4463. [PMID: 35661857 DOI: 10.1039/d2sm00485b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Once limited to chain-growth polymerizations, fine control over polymerization-induced phase separation (PIPS) has recently been demonstrated in rubber-toughened thermoset materials formed through step-growth polymerizations. The domain length scales of these thermoset materials can be elegantly tuned by utilizing a binary mixture of curing agents (CAs) that individually yield disparate morphologies. Importantly, varying the composition of the binary mixture affects characteristics of the materials such as glass transition temperature and tensile behavior. Here, we establish a full phase diagram of PIPS in a rubber-toughened epoxy system tuned by a binary CA mixture to provide a robust framework of phase behaviour. X-Ray scattering in situ and post-PIPS is employed to elucidate the PIPS mechanism whereby an initial polymerization-induced compositional fluctuation causes nanoscale phase separation of rubber and epoxy components prior to local chain crosslinking and potential macrophase separation. We further demonstrate the universality of this approach by alternatively employing binary epoxy or binary rubber mixtures to achieve broad variations in morphology and glass transitions.
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Affiliation(s)
- Samuel C Leguizamon
- Department of Organic Materials Science, Sandia National Laboratories, Albuquerque, NM, 87185, USA.
| | - Juhong Ahn
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Sangwoo Lee
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Brad H Jones
- Department of Organic Materials Science, Sandia National Laboratories, Albuquerque, NM, 87185, USA.
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Leguizamon SC, Powers J, Ahn J, Dickens S, Lee S, Jones BH. Polymerization-Induced Phase Separation in Rubber-Toughened Amine-Cured Epoxy Resins: Tuning Morphology from the Nano- to Macro-scale. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01208] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Samuel C. Leguizamon
- Material, Physical, and Chemical Sciences Center, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Jackson Powers
- Material, Physical, and Chemical Sciences Center, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Juhong Ahn
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Sara Dickens
- Material, Physical, and Chemical Sciences Center, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Sangwoo Lee
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Brad H. Jones
- Material, Physical, and Chemical Sciences Center, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
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