1
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Ding N, Hosein ID. Multidirectional Polymer Waveguide Lattices for Enhanced Ultrawide-Angle Light Capture in Silicon Solar Cells. ACS APPLIED ENERGY MATERIALS 2022; 5:9980-9993. [PMID: 36034761 PMCID: PMC9400022 DOI: 10.1021/acsaem.2c01630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 07/13/2022] [Indexed: 06/15/2023]
Abstract
We report the synthesis and characterization of a polymer thin-film structure consisting of two intersecting broadband optical waveguide lattices, and its performance in wide-angle optical energy collection and conversion in silicon solar cells. The structures are synthetically organized via the concurrent irradiation of photoreactive polymer blends by two arrays of intersecting, microscale optical beams transmitted through the medium. Through optical beam-induced photopolymerization and photopolymerization-induced phase separation, well-organized lattices are produced comprising of cylindrical core-cladding waveguide architectures that intersect one another. The optical waveguide properties of the lattices transform the transmission characteristics of the polymer film so that incident optical energy is collected and transmitted along the waveguide axes, rather than their natural directions dictated by refraction, thereby creating efficient light-collecting capability. The embedded structures collectively impart their wide-angle acceptance ranges to enable the film to efficiently collect and interact with light over a large angular range (±70°). When employed as the encapsulant material for a commercial silicon solar cell, the novel light collection and transmission properties result in greater wide-angle conversion efficiency and electrical current density, compared to a single vertically aligned waveguide array. The sustained and greater conversion of light afforded by the encapsulating optical material promises to increase solar cell performance by enabling ultrawide-angle solar energy conversion.
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2
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Lee BJ, Hsiao K, Lipkowitz G, Samuelsen T, Tate L, DeSimone JM. Characterization of a 30 µm pixel size CLIP-based 3D printer and its enhancement through dynamic printing optimization. ADDITIVE MANUFACTURING 2022; 55:102800. [PMID: 35602181 PMCID: PMC9121862 DOI: 10.1016/j.addma.2022.102800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Resolving microscopic and complex 3D polymeric structures while maintaining high print speeds in additive manufacturing has been challenging. To achieve print precision at micrometer length scales for polymeric materials, most 3D printing technologies utilize the serial voxel printing approach that has a relatively slow print speed. Here, a 30-µm-resolution continuous liquid interface production (CLIP)-based 3D printing system for printing polymeric microstructures is described. This technology combines the high-resolution from projection microstereolithography and the fast print speed from CLIP, thereby achieving micrometer print resolution at x103 times faster than other high-resolution 3D printing technologies. Print resolutions in both lateral and vertical directions were characterized, and the printability of minimum 30 µm features in 2D and 3D has been demonstrated. Through dynamic printing optimization, a method that varies the print parameters (e.g. exposure time, UV intensity, and dark time) for each print layer, overhanging struts at various thicknesses spanning 1 order of magnitude (25 µm - 200 µm) in a single print are resolvable. Taken together, this work illustrates that the micro-CLIP 3D printing technology, in combination with dynamic printing optimization, has the high resolution needed to enable manufacturing of exquisitely detailed and gradient 3D structures, such as terraced microneedle arrays and micro-lattice structures, while maintaining high print speeds.
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Affiliation(s)
- Brian J. Lee
- Department of Radiology, Stanford University, Stanford, CA, 94305
- Department of Mechanical Engineering, Sungkyunkwan University, Suwon, Republic of Korea
- These authors contributed equally (Brian J Lee, Kaiwen Hsiao)
| | - Kaiwen Hsiao
- Department of Radiology, Stanford University, Stanford, CA, 94305
- These authors contributed equally (Brian J Lee, Kaiwen Hsiao)
| | - Gabriel Lipkowitz
- Department of Mechanical Engineering, Stanford University, Stanford, CA, 94305
| | - Tim Samuelsen
- Department of Mechanical Engineering, Stanford University, Stanford, CA, 94305
| | - Lee Tate
- Digital Light Innovations, Austin, TX, 78728
| | - Joseph M. DeSimone
- Department of Radiology, Stanford University, Stanford, CA, 94305
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94305
- Graduate School of Business, Stanford University, Stanford, CA, 94305
- Department of Materials Science & Engineering, Stanford University, Stanford, CA, 94305
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3
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Consolati G, Quasso F, Yaynik E, Briatico Vangosa F, Šauša O, Ehrmann K, Švajdlenková H. Thermal expansion of free volume in "classic" and regulated dimethacrylates: photocured directly and via a mask to study pillar formation. Phys Chem Chem Phys 2022; 24:14299-14309. [PMID: 35642648 DOI: 10.1039/d2cp00882c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The temperature dependence of free volume in dimethacrylates (poly2M), cured by direct irradiation (poly2M-A) or via a mask (poly2M-B), and in a thiol-based 2M sample (poly2M-co-EDDT), was investigated by positron annihilation lifetime spectroscopy (PALS) and dilatometry (DIL) to study the influence of thiol regulation on the microstructure via free volume characteristics. It was found that the free volume fraction as determined from experimental data by using the standard spherical approach for the hole shapes showed systematic differences from the analogous quantity as evaluated from the lattice-hole theory. Much better results were obtained for cylindrical holes, which expand 'anisotropically' in poly2M samples and 'isotropically' in the poly2M-co-EDDT resin. In addition, the hydrogen bond changes and the conversion of monomers in cured samples studied by near infra-red spectroscopy (NIR) revealed spectrum-structure correlations for the final cured thermosets.
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Affiliation(s)
- Giovanni Consolati
- Department of Aerospace Science and Technology, Politecnico di Milano, via La Masa 34, 20156, Milano, Italy.
| | - Fiorenza Quasso
- Department of Aerospace Science and Technology, Politecnico di Milano, via La Masa 34, 20156, Milano, Italy.
| | - Erkin Yaynik
- Department of Aerospace Science and Technology, Politecnico di Milano, via La Masa 34, 20156, Milano, Italy.
| | - Francesco Briatico Vangosa
- Department of Chemistry, Materials and Chemical Engineering 'Giulio Natta', Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | - Ondrej Šauša
- Department of Nuclear Physics, Institute of Physics of SAS, Dúbravská cesta 9, 845 11, Bratislava, Slovakia.,Department of Nuclear Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, Ilkovičova 6, 842 15, Bratislava, Slovakia
| | - Katharina Ehrmann
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/163 MC, 1060, Vienna, Austria
| | - Helena Švajdlenková
- Department of Synthesis and Characterization of polymers, Polymer Institute of SAS, Dúbravská cesta 9, 845 41, Bratislava, Slovakia.
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4
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Ding N, Hosein ID. Simulations of Structure and Morphology in Photoreactive Polymer Blends under Multibeam Irradiation. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:6700-6715. [PMID: 35493698 PMCID: PMC9037196 DOI: 10.1021/acs.jpcc.1c09993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 03/21/2022] [Indexed: 06/14/2023]
Abstract
We present a theoretical study of the organization of photoreactive polymer blends under irradiation by multiple arrays of intersecting optical beams. In a simulated medium possessing an integrated intensity-dependent refractive index, optical beams undergo self-focusing and reduced divergence. A corresponding intensity-dependent increase in molecular weight induces polymer blend instability and consequent phase separation, whereby the medium can evolve into an intersecting waveguide lattice structure, comprising high refractive index cylindrical cores and a surrounding low refractive index medium (cladding). We conduct simulations for two propagation angles and a range of thermodynamic, kinetic, and polymer blend parameters to establish correlations to structure and morphology. We show that spatially correlated structures, namely, those that have a similar intersecting three-dimensional (3D) pattern as the arrays of intersecting optical beams, are achieved via a balance between the competitive processes of photopolymerization rate and phase separation dynamics. A greater intersection angle of the optical beams leads to higher correlations between structures and the optical beam pattern and a wider parameter space that achieves correlated structures. This work demonstrates the potential to employ complex propagating light patterns to create 3D organized structures in multicomponent photoreactive soft systems.
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5
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Pathreeker S, Chando P, Chen FH, Biria S, Li H, Finkelstein EB, Hosein ID. Superhydrophobic Polymer Composite Surfaces Developed via Photopolymerization. ACS APPLIED POLYMER MATERIALS 2021; 3:4661-4672. [PMID: 34541544 PMCID: PMC8438665 DOI: 10.1021/acsapm.1c00744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 08/04/2021] [Indexed: 06/13/2023]
Abstract
Fabrication of superhydrophobic materials using incumbent techniques involves several processing steps and is therefore either quite complex, not scalable, or often both. Here, the development of superhydrophobic surface-patterned polymer-TiO2 composite materials using a simple, single-step photopolymerization-based approach is reported. The synergistic combination of concurrent, periodic bump-like pattern formation created using irradiation through a photomask and photopolymerization-induced nanoparticle (NP) phase separation enables the development of surface textures with dual-scale roughness (micrometer-sized bumps and NPs) that demonstrate high water contact angles, low roll-off angles, and desirable postprocessability such as flexibility, peel-and-stick capability, and self-cleaning capability. The effect of nanoparticle concentration on surface porosity and consequently nonwetting properties is discussed. Large-area fabrication over an area of 20 cm2, which is important for practical applications, is also demonstrated. This work demonstrates the capability of polymerizable systems to aid in the organization of functional polymer-nanoparticle surface structures.
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Affiliation(s)
- Shreyas Pathreeker
- Department
of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Paul Chando
- Department
of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Fu-Hao Chen
- Department
of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Saeid Biria
- Department
of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Hansheng Li
- Department
of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Eric B. Finkelstein
- Department
of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
- Syracuse
Biomaterials Institute, Syracuse University, Syracuse, New York 13244, United States
| | - Ian D. Hosein
- Department
of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
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6
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Xie H, Basu S, DeMeter EC. Coupling Monte Carlo Light Propagation Method and Curing Kinetic Equations to Model the Degree of Conversion Evolution of UV-Curable Composites. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.1c01585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Haochen Xie
- Department of Manufacturing and Industrial Engineering, The Pennsylvania State University, University Park, Pennsylvania 16801, United States
| | - Saurabh Basu
- Department of Manufacturing and Industrial Engineering, The Pennsylvania State University, University Park, Pennsylvania 16801, United States
| | - Edward C. DeMeter
- Department of Manufacturing and Industrial Engineering, The Pennsylvania State University, University Park, Pennsylvania 16801, United States
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7
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Biria S, Pathreeker S, Genier FS, Chen FH, Li H, Burdin CV, Hosein ID. Gel Polymer Electrolytes Based on Cross-Linked Poly(ethylene glycol) Diacrylate for Calcium-Ion Conduction. ACS OMEGA 2021; 6:17095-17102. [PMID: 34250366 PMCID: PMC8264931 DOI: 10.1021/acsomega.1c02312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 06/01/2021] [Indexed: 06/12/2023]
Abstract
Calcium batteries are promising alternatives to lithium batteries owing to their high energy density, comparable reduction potential, and mineral abundance. However, to meet practical demands in high-performance applications, suitable electrolytes must be developed. Here, we report the synthesis and characterization of polymer gel electrolytes for calcium-ion conduction prepared by the photo-cross-linking of poly(ethylene glycol) diacrylate (PEGDA) in the presence of solutions of calcium salts in a mixture of ethylene carbonate (EC) and propylene carbonate (PC) solvents. The results show room-temperature conductivity between 10-5 and 10-4 S/cm, electrochemical stability windows of ∼3.8 V, full dissociation of the salt, and minimal coordination with the PEGDA backbone. Cycling in symmetric Ca metal cells proceeds but with increasing overpotentials, which can be attributed to interfacial impedance between the electrolyte and calcium surface, which inhibits charge transfer. Calcium may still be plated and stripped yielding high-purity deposits and no indication of significant electrolyte breakdown, indicating that high overpotentials are associated with an electrically insulating, yet ion-permeable solid electrolyte interface (SEI). This work provides a contribution to the study and understanding of polymer gel materials toward their improvement and application as electrolytes for calcium batteries.
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8
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Xie H, Basu S, DeMeter EC. Combining FDTD and Curing Kinetic Equations to Model the Degree of Conversion Evolution of UV-Curable Systems. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.1c01213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Haochen Xie
- Department of Manufacturing and Industrial Engineering, The Pennsylvania State University, University Park, Pennsylvania 16801, United States
| | - Saurabh Basu
- Department of Manufacturing and Industrial Engineering, The Pennsylvania State University, University Park, Pennsylvania 16801, United States
| | - Edward C. DeMeter
- Department of Manufacturing and Industrial Engineering, The Pennsylvania State University, University Park, Pennsylvania 16801, United States
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9
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Adão RMR, Caño-García M, Maibohm C, Nieder JB. Photonic polymeric structures and electrodynamics simulation method based on a coupled oscillator finite-difference time-domain (O-FDTD) approach. OPTICS EXPRESS 2021; 29:11903-11916. [PMID: 33984962 DOI: 10.1364/oe.414211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 02/26/2021] [Indexed: 06/12/2023]
Abstract
We use femtosecond laser-based two-photon polymerization (TPP) to fabricate a 2.5D micropillar array. Using an angular detection setup, we characterize the structure's scattering properties and compare the results against simulation results obtained from a novel electrodynamics simulation method. The algorithm employs a modified formulation of the Lorentz Oscillator Model and a leapfrog time differentiation to define a 2D coupled Oscillator Finite-Difference Time-Domain (O-FDTD). We validate the model by presenting several simulation examples that cover a wide range of photonic components, such as multi-mode interference splitters, photonic crystals, ring resonators, and Mach-Zehnder interferometers.
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10
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Pathreeker S, Chen FH, Biria S, Hosein ID. Observation of intensity dependent phase-separation in photoreactive monomer-nanoparticle formulations under non-uniform visible light irradiation. SOFT MATTER 2020; 16:7256-7269. [PMID: 32632433 DOI: 10.1039/d0sm00922a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We report observations of photopolymerization driven phase-separation in a mixture of a photo-reactive monomer and inorganic nanoparticles. The mixture is irradiated with visible light possessing a periodic intensity profile that elicits photopolymerization along the depth of the mixture, establishing a competition between photo-crosslinking and thermodynamically favorable phase-separating behavior inherent to the system. In situ Raman spectroscopy was used to monitor the polymerization reaction and morphology evolution, and reveals a key correlation between irradiation intensity and composite morphology extending the entire depth of the mixture, i.e. unhindered phase-separation at low irradiation intensity and arrested phase-separation at high irradiation intensity. 3D Raman volume mapping and energy dispersive X-ray mapping confirm that the intensity-dependent irradiation process dictates the extent of phase separation, enabling single-parameter control over phase evolution and subsequent composite morphology. These observations can potentially enable a single-step route to develop polymer-inorganic composite materials with tunable morphologies.
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Affiliation(s)
- Shreyas Pathreeker
- Department of Biomedical & Chemical Engineering, Syracuse University, Syracuse, New York 13244, USA.
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11
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Okamura H, Nishijima Y, Noguchi D, Fukumoto T, Suzuki Y. Suppressed Oxygen Inhibition in UV Curable Formulations Using a Diene as an Additive. J PHOTOPOLYM SCI TEC 2020. [DOI: 10.2494/photopolymer.33.349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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12
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Chen FH, Biria S, Li H, Hosein ID. Microfiber Optic Arrays as Top Coatings for Front-Contact Solar Cells toward Mitigation of Shading Loss. ACS APPLIED MATERIALS & INTERFACES 2019; 11:47422-47427. [PMID: 31755693 DOI: 10.1021/acsami.9b17803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Microfiber optic array structures are fabricated and employed as an optical structure overlaying a front-contact silicon solar cell. The arrays are synthesized through light-induced self-writing in a photo-crosslinking acrylate resin, which produces periodically spaced, high-aspect-ratio, and vertically aligned tapered microfibers deposited on a transparent substrate. The structure is then positioned over and sealed onto the solar cell surface. Their fiber optic properties enable collection of non-normal incident light, allowing the structure to mitigate shading loss through the redirection of incident light away from contacts and toward the solar cell. Angle-averaged external quantum efficiency increases nominally by 1.61%, resulting in increases in short-circuit current density up to 1.13 mA/cm2. This work demonstrates a new approach to enhance light collection and conversion using a scalable, straightforward, light-based additive manufacturing process.
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Affiliation(s)
- Fu-Hao Chen
- Department of Biomedical and Chemical Engineering , Syracuse University , Syracuse , New York 13244 , United States
| | - Saeid Biria
- Department of Biomedical and Chemical Engineering , Syracuse University , Syracuse , New York 13244 , United States
| | - Hansheng Li
- Department of Biomedical and Chemical Engineering , Syracuse University , Syracuse , New York 13244 , United States
| | - Ian D Hosein
- Department of Biomedical and Chemical Engineering , Syracuse University , Syracuse , New York 13244 , United States
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Lin JT, Liu HW, Chen KT, Cheng DC. Modeling the Kinetics, Curing Depth, and Efficacy of Radical-Mediated Photopolymerization: The Role of Oxygen Inhibition, Viscosity, and Dynamic Light Intensity. Front Chem 2019; 7:760. [PMID: 31799237 PMCID: PMC6863961 DOI: 10.3389/fchem.2019.00760] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 10/23/2019] [Indexed: 01/06/2023] Open
Abstract
Kinetic equations for a modeling system with type-I radical-mediated and type-II oxygen-mediated pathways are derived and numerically solved for the photopolymerization efficacy and curing depth, under the quasi-steady state assumption, and bimolecular termination. We show that photopolymerization efficacy is an increasing function of photosensitizer (PS) concentration (C 0) and the light dose at transient state, but it is a decreasing function of the light intensity, scaled by [C 0/I 0]0.5 at steady state. The curing (or cross-link) depth is an increasing function of C 0 and light dose (time × intensity), but it is a decreasing function of the oxygen concentration, viscosity effect, and oxygen external supply rate. Higher intensity results in a faster depletion of PS and oxygen. For optically thick polymers (>100 um), light intensity is an increasing function of time due to PS depletion, which cannot be neglected. With oxygen inhibition effect, the efficacy temporal profile has an induction time defined by the oxygen depletion rate. Efficacy is also an increasing function of the effective rate constant, K = k'/ k T 0 . 5 , defined by the radical producing rate (k') and the bimolecular termination rate (k T). In conclusion, the curing depth has a non-linear dependence on the PS concentration, light intensity, and dose and a decreasing function of the oxygen inhibition effect. Efficacy is scaled by [C 0/I 0]0.5 at steady state. Analytic formulas for the efficacy and curing depth are derived, for the first time, and utilized to analyze the measured pillar height in microfabrication. Finally, various strategies for improved efficacy and curing depth are discussed.
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Affiliation(s)
| | - Hsia-Wei Liu
- Department of Life Science, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Kuo-Ti Chen
- Graduate Institute of Applied Science and Engineering, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Da-Chuan Cheng
- Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan
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14
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Lin JT, Cheng DC, Chen KT, Liu HW. Dual-Wavelength (UV and Blue) Controlled Photopolymerization Confinement for 3D-Printing: Modeling and Analysis of Measurements. Polymers (Basel) 2019; 11:E1819. [PMID: 31698682 PMCID: PMC6918369 DOI: 10.3390/polym11111819] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 10/31/2019] [Accepted: 11/01/2019] [Indexed: 01/16/2023] Open
Abstract
The kinetics and modeling of dual-wavelength (UV and blue) controlled photopolymerization confinement (PC) are presented and measured data are analyzed by analytic formulas and numerical data. The UV-light initiated inhibition effect is strongly monomer-dependent due to different C=C bond rate constants and conversion efficacies. Without the UV-light, for a given blue-light intensity, higher initiator concentration (C10) and rate constant (k') lead to higher conversion, as also predicted by analytic formulas, in which the total conversion rate (RT) is an increasing function of C1 and k'R, which is proportional to k'[gB1C1]0.5. However, the coupling factor B1 plays a different role that higher B1 leads to higher conversion only in the transient regime; whereas higher B1 leads to lower steady-state conversion. For a fixed initiator concentration C10, higher inhibitor concentration (C20) leads to lower conversion due to a stronger inhibition effect. However, same conversion reduction was found for the same H-factor defined by H0 = [b1C10 - b2C20]. Conversion of blue-only are much higher than that of UV-only and UV-blue combined, in which high C20 results a strong reduction of blue-only-conversion, such that the UV-light serves as the turn-off (trigger) mechanism for the purpose of spatial confirmation within the overlap area of UV and blue light. For example, UV-light controlled methacrylate conversion of a glycidyl dimethacrylate resin is formulated with a tertiary amine co-initiator, and butyl nitrite. The system is subject to a continuous exposure of a blue light, but an on-off exposure of a UV-light. Finally, we developed a theoretical new finding for the criterion of a good material/candidate governed by a double ratio of light-intensity and concentration, [I20C20]/[I10C10].
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Affiliation(s)
| | - Da-Chuan Cheng
- Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung City 404, Taiwan;
| | - Kuo-Ti Chen
- Graduate Institute of Applied Science and Engineering, Fu Jen Catholic University, New Taipei City 242, Taiwan;
| | - Hsia-Wei Liu
- Department of Life Science, Fu Jen Catholic University, New Taipei City 242, Taiwan
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15
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Thiol-Ene Photopolymerization: Scaling Law and Analytical Formulas for Conversion Based on Kinetic Rate and Thiol-Ene Molar Ratio. Polymers (Basel) 2019; 11:polym11101640. [PMID: 31658683 PMCID: PMC6835589 DOI: 10.3390/polym11101640] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 10/03/2019] [Accepted: 10/07/2019] [Indexed: 11/17/2022] Open
Abstract
Kinetics and analytical formulas for radical-mediated thiol-ene photopolymerization were developed in this paper. The conversion efficacy of thiol-ene systems was studied for various propagation to chain transfer kinetic rate-ratio (RK), and thiol-ene concentration molar-ratio (RC). Numerical data were analyzed using analytical formulas and compared with the experimental data. We demonstrated that our model for a thiol-acrylate system with homopolymerization effects, and for a thiol-norbornene system with viscosity effects, fit much better with the measured data than a previous model excluding these effects. The general features for the roles of RK and RC on the conversion efficacy of thiol (CT) and ene (CV) are: (i) for RK = 1, CV and CT have the same temporal profiles, but have a reversed dependence on RC; (ii) for RK >> 1, CT are almost independent of RC; (iii) for RK << 1, CV and CT have the same profiles and both are decreasing functions of the homopolymerization effects defined by kCV; (iv) viscosity does not affect the efficacy in the case of RK >> 1, but reduces the efficacy of CV for other values of RK. For a fixed light dose, higher light intensity has a higher transient efficacy but a lower steady-state conversion, resulting from a bimolecular termination. In contrast, in type II unimolecular termination, the conversion is mainly governed by the light dose rather than its intensity. For optically thick polymers, the light intensity increases with time due to photoinitiator depletion, and thus the assumption of constant photoinitiator concentration (as in most previous models) suffers an error of 5% to 20% (underestimated) of the crosslink depth and the efficacy. Scaling law for the overall reaction order, defined by [A]m[B]n and governed by the types of ene and the rate ratio is discussed herein. The dual ratio (RK and RC) for various binary functional groups (thiol-vinyl, thiol-acrylate, and thiol-norbornene) may be tailored to minimize side effects for maximal monomer conversion or tunable degree of crosslinking.
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16
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Santos WG, Mattiucci F, Ribeiro SJL. Polymerization Rate Modulated by Tetraarylborate Anion Structure: Direct Correlation of Hammett Substituent Constant with Polymerization Kinetics of 2-Hydroxyethyl Methacrylate. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01361] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Willy G. Santos
- Institute of Chemistry, São Paulo State University - UNESP, CP 355, Araraquara, SP 14801-970, Brazil
| | - Fernando Mattiucci
- Instituto de Quı́mca de São Carlos, Universidade de São Paulo, Av. Trabalhador São Carlense 400, CP 780, CEP 13560-970, São Carlos, SP, Brazil
| | - Sidney J. L. Ribeiro
- Institute of Chemistry, São Paulo State University - UNESP, CP 355, Araraquara, SP 14801-970, Brazil
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17
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Biria S, Hosein ID. Superhydrophobic Microporous Substrates via Photocuring: Coupling Optical Pattern Formation to Phase Separation for Process-Tunable Pore Architectures. ACS APPLIED MATERIALS & INTERFACES 2018; 10:3094-3105. [PMID: 29320157 DOI: 10.1021/acsami.7b16003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present a new approach to synthesize microporous surfaces through the combination of photopolymerization-induced phase separation and light pattern formation in photopolymer-solvent mixtures. The mixtures are irradiated with a wide-area light pattern consisting of high and low intensity regions. This light pattern undergoes self-focusing and filamentation, thereby preserving its spatial profile through the mixture. Over the course of irradiation, the mixture undergoes phase separation, with the polymer and solvent located in the bright and dark regions of the light profile, respectively, to produce a binary phase morphology with a congruent arrangement as the optical pattern. A congruently arranged microporous structure is attained upon solvent removal. The microporous surface structure can be varied by changing the irradiating light profile via photomask design. The porous architecture can be further tuned through the relative weight fractions of photopolymer and solvent in the mixture, resulting in porosities ranging from those with discrete and uniform pore sizes to hierarchical pore distributions. All surfaces become superhydrophobic (water contact angles >150°) when spray-coated with a thin layer of polytetrafluoroethylene nanoparticles. The water contact angles can be enhanced by changing the surface porosity via the processing conditions. This is a scalable and tunable approach to precisely control microporous surface structure in thin films to create functional surfaces and antiwetting coatings.
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Affiliation(s)
- Saeid Biria
- Department of Biomedical and Chemical Engineering, Syracuse University , Syracuse, New York 13244, United States
| | - Ian D Hosein
- Department of Biomedical and Chemical Engineering, Syracuse University , Syracuse, New York 13244, United States
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