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Kowalski BA, McLeod RR. Design concepts for diffusive holographic photopolymers. ACTA ACUST UNITED AC 2016. [DOI: 10.1002/polb.24011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Benjamin A. Kowalski
- Department of ElectricalComputer, and Energy Engineering, University of Colorado at Boulder425 UCBBoulder Colorado80309
| | - Robert R. McLeod
- Department of ElectricalComputer, and Energy Engineering, University of Colorado at Boulder425 UCBBoulder Colorado80309
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2
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Liu S, Gleeson MR, Guo J, Sheridan JT. High Intensity Response of Photopolymer Materials for Holographic Grating Formation. Macromolecules 2010. [DOI: 10.1021/ma101723y] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Shui Liu
- School of Electrical, Electronic and Mechanical Engineering, Communication and Optoelectronic Research Centre, The SFI-Strategic Research Cluster in Solar Energy Conversion, College of Engineering, Mathematical and Physical Sciences, University College Dublin, Belfield, Dublin 4, Ireland
| | - Michael R. Gleeson
- School of Electrical, Electronic and Mechanical Engineering, Communication and Optoelectronic Research Centre, The SFI-Strategic Research Cluster in Solar Energy Conversion, College of Engineering, Mathematical and Physical Sciences, University College Dublin, Belfield, Dublin 4, Ireland
| | - Jinxin Guo
- School of Electrical, Electronic and Mechanical Engineering, Communication and Optoelectronic Research Centre, The SFI-Strategic Research Cluster in Solar Energy Conversion, College of Engineering, Mathematical and Physical Sciences, University College Dublin, Belfield, Dublin 4, Ireland
| | - John T. Sheridan
- School of Electrical, Electronic and Mechanical Engineering, Communication and Optoelectronic Research Centre, The SFI-Strategic Research Cluster in Solar Energy Conversion, College of Engineering, Mathematical and Physical Sciences, University College Dublin, Belfield, Dublin 4, Ireland
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4
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Busse K, Peetla C, Kressler J. Water surface covering of fluorinated amphiphilic triblock copolymers: surface pressure-area and X-ray reflectivity investigations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:6975-82. [PMID: 17503856 DOI: 10.1021/la0637059] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Monolayers of ABA amphiphilic triblock block copolymers are studied using surface pressure-area and X-ray reflectivity (XR) measurements. The triblock copolymers are composed of long poly(ethylene oxide) (PEO) middle blocks with poly((perfluorohexyl)ethyl methacrylate) (PFMA) end blocks. The surface pressure-area isotherms of water-insoluble species show two pseudoplateaus. The plateau at low surface pressure is consistent with the pseudoplateau observed for PEO copolymers in the literature. The plateau in the brush region can be assigned to the horizontal to vertical rearrangement of whole PFMA chains at the air-water interface, which was followed by XR measurements. For water-soluble species with a very low amount of PFMA no (significant) second pseudoplateau and no enrichment of PFMA at the air-water interface were observed.
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Affiliation(s)
- Karsten Busse
- Institute of Physical Chemistry, Department of Chemistry, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany.
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Meng S, Duran H, Hu J, Kyu T, Natarajan LV, Tondiglia VP, Sutherland RL, Bunning TJ. Influence of Photopolymerization Reaction Kinetics on Diffraction Efficiency of H-PDLC Undergoing Photopatterning Reaction in Mixtures of Acrylic Monomer/Nematic Liquid Crystals. Macromolecules 2007. [DOI: 10.1021/ma070135q] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Scott Meng
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325-0301; Department of Chemistry, University of Akron, Akron, Ohio 44325-3601; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
| | - Hatice Duran
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325-0301; Department of Chemistry, University of Akron, Akron, Ohio 44325-3601; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
| | - Jun Hu
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325-0301; Department of Chemistry, University of Akron, Akron, Ohio 44325-3601; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
| | - Thein Kyu
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325-0301; Department of Chemistry, University of Akron, Akron, Ohio 44325-3601; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
| | - Lalgudi V. Natarajan
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325-0301; Department of Chemistry, University of Akron, Akron, Ohio 44325-3601; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
| | - Vincent P. Tondiglia
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325-0301; Department of Chemistry, University of Akron, Akron, Ohio 44325-3601; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
| | - Richard L. Sutherland
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325-0301; Department of Chemistry, University of Akron, Akron, Ohio 44325-3601; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
| | - Timothy J. Bunning
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325-0301; Department of Chemistry, University of Akron, Akron, Ohio 44325-3601; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
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6
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Joncheray TJ, Denoncourt KM, Meier MAR, Schubert US, Duran RS. Two-dimensional self-assembly of linear poly(ethylene oxide)-b-poly(epsilon-caprolactone) copolymers at the air-water interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:2423-9. [PMID: 17243736 DOI: 10.1021/la062626u] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The interfacial properties of amphiphilic linear diblock copolymers based on poly(ethylene oxide) and poly(epsilon-caprolactone) (PEO-b-PCL) were studied at the air-water (A/W) interface by surface pressure measurements (isotherms and hysteresis experiments). The resulting Langmuir monolayers were transferred onto mica substrates and the Langmuir-Blodgett (LB) film morphologies were investigated by atomic force microscopy (AFM). All block copolymers had the same PEO segment (Mn = 2670 g/mol) and different PCL chain lengths (Mn = 1270; 2110; 3110 and 4010 g/mol). Isothermal characterization of the block copolymer samples indicated the presence of three distinct phase transitions around 6.5, 10.5, and 13.5 mN/m. The phase transitions at 6.5 and 13.5 mN/m correspond to the dissolution of the PEO segments in the water subphase and crystallization of the PCL blocks above the interface similarly as for the corresponding homopolymers, respectively. The phase transition at 10.5 mN/m was not observed for the homopolymers alone or for their blends and arises from a brush formation of the PEO segments anchored underneath the adsorbed hydrophobic PCL segments. AFM analysis confirmed the presence of PCL crystals in the LB films with unusual hairlike/needlelike architectures significantly different from those obtained for PCL homopolymers.
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Affiliation(s)
- Thomas J Joncheray
- The George and Josephine Butler Polymer Research Laboratory, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL 32611-7200, USA
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7
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Woo JY, Kim BK. Surfactant Effects on Morphology and Switching of Holographic PDLCs Based on Polyurethane Acrylates. Chemphyschem 2007; 8:175-80. [PMID: 17146810 DOI: 10.1002/cphc.200600482] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Effects of octanoic acid (OA) on the morphology, diffraction efficiency, and electro-optic properties of the transmission mode of holographic polymer-dispersed liquid crystals (HPDLC) are studied. Droplet size decreases with increasing OA content (0-9 %), and this leads to a monotonic increase in off-state diffraction with increasing OA content. However, on-state diffraction decreases with increasing applied voltage and shows a minimum at 6 % OA, for which minimum switching voltage (5 V microm(-1)) and maximum contrast ratio (10) are obtained. Rise time and decay time decrease with increasing OA content. Interposition of OA between polymer and LC droplet is theoretically predicted by the spreading coefficient (lambda>0) calculated on the basis of the solubility parameter, while the coalescence behavior of droplets is described by a dimensionless group (gamma d rho / mu(2)) called coalescence number.
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Affiliation(s)
- Ju Yeon Woo
- Department of Polymer Science and Engineering, Pusan National University, Busan 609-735, Korea
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Ni S, Lee W, Li B, Esker AR. Thermodynamics of the liquid expanded to condensed phase transition of poly(L-lactic acid) in Langmuir monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:3672-7. [PMID: 16584242 DOI: 10.1021/la060084a] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Surface pressure-area per monomer (pi-A) isotherms show that poly(L-lactic acid) (PLLA) Langmuir monolayers exhibit a liquid expanded-to-condensed (LE/LC) phase transition at low surface pressure. Brewster angle microscopy images show circular domains where the LC phase is surrounded by the LE phase during phase coexistence. Morphology studies via atomic force microscopy show that well-ordered patterns are only observed for Langmuir-Blodgett films prepared in the LC phase, while no ordered features are observed in the LE phase. The morphological differences confirm that during the LE/LC phase transition PLLA molecules form well-ordered structures at the air/water interface. Analysis by the two-dimensional Clausius-Clapeyron equation is used to predict the critical parameters (X(c)). Both critical parameters, the critical temperature (T(c)) and the critical pressure (pi(c)), increase with increasing number average molar mass (M(n)) as X(c) = X(c,infinity) - KM(n)(-1), where X(c,infinity) is the value of the critical parameter at infinite molar mass and K is a constant. For PLLA T(c,infinity) = 36.2 +/- 0.3 degrees C and pi(c,infinity) = 4.53 +/- 0.06 mN x m(-1). This study provides a model polymer system for examining critical behavior in two dimensions.
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Affiliation(s)
- Suolong Ni
- Department of Chemistry (0212), Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
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9
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Kim Y, Pyun J, Fréchet JMJ, Hawker CJ, Frank CW. The dramatic effect of architecture on the self-assembly of block copolymers at interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:10444-58. [PMID: 16262305 DOI: 10.1021/la047122f] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Dramatic morphological changes are observed in the Langmuir-Blodgett (LB) film assemblies of poly(ethylene glycol)-b-(styrene-r-benzocyclobutene) block copolymer (PEG-b-(S-r-BCB)) after intramolecular cross-linking of the S-r-BCB block to form a linear-nanoparticle structure. To isolate architectural effects and allow direct comparison, the linear block copolymer precursor and the linear-nanoparticle block copolymer resulting from selective intramolecular cross-linking of the BCB units were designed to have exactly the same molecular weight and chemical composition but different architecture. It was found that the effect of architecture is pronounced with these macromolecular isomers, which self-assemble into dramatically different surface aggregates. The linear block copolymer forms disklike surface assemblies over the range of compression states, while the linear-nanoparticle block copolymer exhibits long (>10 microm) wormlike aggregates whose length increases as a function of increasing cross-linking density. It is shown that the driving force behind the morphological change is a combination of the altered molecular geometry and the restricted degree of stretching of the nanoparticle block because of the intramolecular cross-linking. A modified approach to interpret the pi-A isotherm, which includes presence of the block copolymer aggregates, is also presented, while the surface rheological properties of the block copolymers at the air-water interface provide in-situ evidence of the aggregates' presence at the air-water interface.
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Affiliation(s)
- Yoojin Kim
- Department of Chemical Engineering, Stanford University, California 94305-5025, USA
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10
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Blomqvist BR, Wärnheim T, Claesson PM. Surface rheology of PEO-PPO-PEO triblock copolymers at the air-water interface: comparison of spread and adsorbed layers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:6373-84. [PMID: 15982044 DOI: 10.1021/la0467584] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The dilatational rheological properties of monolayers of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)-type block copolymers at the air-water interface have been investigated by employing an oscillating ring trough method. The properties of adsorbed monolayers were compared to spread layers over a range of surface concentrations. The studied polymers were PEO26-PPO39-PEO26 (P85), PEO103-PPO40-PEO103 (F88), and PEO99-PPO65-PEO99 (F127). Thus, two of the polymers have similar PPO block size and two of them have similar PEO block size, which allows us to draw conclusions about the relationship between molecular structure and surface dilatational rheology. The dilatational properties of adsorbed monolayers were investigated as a function of time and bulk solution concentration. The time dependence was found to be rather complex, reflecting structural changes in the layer. When the dilatational modulus measured at different concentrations was replotted as a function of surface pressure, one unique master curve was obtained for each polymer. It was found that the dilatational behavior of spread (Langmuir) and adsorbed (Gibbs) monolayers of the same polymer is close to identical up to surface concentrations of approximately 0.7 mg/m2. At higher coverage, the properties are qualitatively alike with respect to dilatational modulus, although some differences are noticeable. Relaxation processes take place mainly within the interfacial layers by a redistribution of polymer segments. Several conformational transitions were shown to occur as the area per molecule decreased. PEO desorbs significantly from the interface at segmental areas below 20 A(2), while at higher surface coverage, we propose that segments of PPO are forced to leave the interface to form a mixed sublayer in the aqueous region.
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Logan JL, Masse P, Dorvel B, Skolnik AM, Sheiko SS, Francis R, Taton D, Gnanou Y, Duran RS. AFM study of micelle chaining in surface films of polystyrene-block-poly(ethylene oxide) stars at the air/water interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:3424-3431. [PMID: 15807583 DOI: 10.1021/la0468242] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A series of three-arm star block copolymers were examined using atomic force microscopy (AFM). These stars consisted of a polystyrene core composed of ca. 111 styrene units/branch with poly(ethylene oxide) (PEO) chains at the star periphery. Each star contained different amounts of PEO, varying from 107 to 415 ethylene oxide units/branch. The stars were spread as thin films at the air/water interface on a Langmuir trough and transferred onto mica at various surface pressures. Circular domains representing 2D micelle-like aggregated molecules were observed at low pressures. Upon further compression, these domains underwent additional aggregation in a systematic manner, including micellar chaining. At this point, domain area and the number of molecules/domain increased with increasing pressure. In addition, it was found that longer PEO chains led to greater intermolecular separation and less aggregation. These AFM results correspond to attributes seen in the surface pressure-area isotherms of the stars. In addition, they demonstrate the viability of AFM as a quantitative characterization technique.
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Affiliation(s)
- Jennifer L Logan
- The George and Josephine Butler Polymer Research Laboratory, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611-7200, USA
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12
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Li F, Zhou S, You B, Wu L. Kinetic investigations on the UV-induced photopolymerization of nanocomposites by FTIR spectroscopy. J Appl Polym Sci 2005. [DOI: 10.1002/app.22629] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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13
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Falk B, Vallinas SM, Crivello JV. Monitoring photopolymerization reactions with optical pyrometry. ACTA ACUST UNITED AC 2003. [DOI: 10.1002/pola.10602] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Garcia C, Pascual I, Costela A, Garcia-Moreno I, Gomez C, Fimia A, Sastre R. Hologram recording in polyvinyl alcohol/acrylamide photopolymers by means of pulsed laser exposure. APPLIED OPTICS 2002; 41:2613-2620. [PMID: 12022660 DOI: 10.1364/ao.41.002613] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The variation in transmittance produced when a photopolymer is irradiated with a pulsed laser is analyzed and experimental results obtained when diffraction gratings are stored using pulsed exposure are presented. In either case, the influence of the energy of the irradiation pulse, the number of pulses, and the pulse repetition rate were studied. The photopolymer used was an acrylamide/polyvinyl alcohol dry film with a yellow eosin-thiethanol-amine mixture as a photoinitiator system. The recording of the gratings was performed by use of a holographic copying process. The samples were exposed and holograms recorded with a collimated beam from a frequency-doubled Nd:YAG (532 nm) Q-switched laser. Our initial results show that it is possible to obtain diffraction gratings with a diffraction efficiency of 60% and a refractive index modulation up to 2.8 x 10(-3). The energetic sensitivities achieved are close to those obtained with the same material and continuous irradiation without a preprocessing of the gratings.
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Affiliation(s)
- Celia Garcia
- Universidad de Alicante, Departamento Interuniversitario de Optica, Spain.
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Devereaux CA, Baker SM. Surface Features in Langmuir−Blodgett Monolayers of Predominantly Hydrophobic Poly(styrene)−Poly(ethylene oxide) Diblock Copolymer. Macromolecules 2002. [DOI: 10.1021/ma011319m] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- C. A. Devereaux
- Department of Chemistry, Harvey Mudd College, Claremont, California 91711
| | - S. M. Baker
- Department of Chemistry, Harvey Mudd College, Claremont, California 91711
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Holland NB, Xu Z, Vacheethasanee K, Marchant RE. Structure of Poly(ethylene oxide) Surfactant Polymers at Air−Water and Solid−Water Interfaces. Macromolecules 2001. [DOI: 10.1021/ma001215w] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nolan B. Holland
- Departments of Macromolecular Science and Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106
| | - Zhong Xu
- Departments of Macromolecular Science and Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106
| | - Katanchalee Vacheethasanee
- Departments of Macromolecular Science and Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106
| | - Roger E. Marchant
- Departments of Macromolecular Science and Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106
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Zhang X, Xu J, Okawa K, Katsuyama Y, Gong J, Osada Y, Chen K. In Situ Monitoring of Hydrogel Polymerization Using Speckle Interferometry. J Phys Chem B 1999. [DOI: 10.1021/jp9842998] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xianmin Zhang
- Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Jian Xu
- Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Kaori Okawa
- Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Yoshinori Katsuyama
- Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Jianping Gong
- Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Yoshihito Osada
- Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Kangsheng Chen
- Department of Information and Electronic Engineering, Zhejiang University, Hangzhou 310027, China
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Blaya S, Carretero L, Mallavia R, Fimia A, Madrigal RF. Holography as a technique for the study of photopolymerization kinetics in dry polymeric films with a nonlinear response. APPLIED OPTICS 1999; 38:955-962. [PMID: 18305697 DOI: 10.1364/ao.38.000955] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A method is reported that makes use of holography to study the kinetics of the radical photopolymerization of acrylamide in a polyvinyl alcohol when the Kogelnik theory is applied. A mechanism of unimolecular termination by the radicals that initiate the polymerization reaction is postulated to calculate the quantum yield, the molar-extinction coefficient, the index of refraction, and the thickness of the film. The conversion percentage of monomers is obtained along with the ratio of rate constants of the mechanism of polymerization from the nonlinear fit of the transmittance curves, their angular response, and the temporal evolution of diffraction efficiency. Compared with previous holographic techniques, this method has the advantage of predicting these chemical parameters using all the data points of the temporal diffraction efficiency variation rather than being restricted to the linear zone of these curves. In this way the whole reaction process, not just the initial process, is taken into account.
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Affiliation(s)
- S Blaya
- Departamento de Ciencias Experimentales y Tecnología, Universidad Miguel Hernández, Campus de Elche Edificio La Galia, Av del Ferrocarril syn Apdo. 03202, Elche Alicante, Spain
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Chatwin C, Farsari M, Huang S, Heywood M, Birch P, Young R, Richardson J. UV Microstereolithography System that uses Spatial Light Modulator Technology. APPLIED OPTICS 1998; 37:7514-7522. [PMID: 18301586 DOI: 10.1364/ao.37.007514] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A new stereophotolithography technique utilizing a spatial light modulator (SLM) to create three-dimensional components with a planar, layer-by-layer process of exposure is described. With this procedure it is possible to build components with dimensions in the range of 50 mum-50 mm and feature sizes as small as 5 mum with a resolution of 1 mum. A polysilicon thin-film twisted nematic SVGA SLM is used as the dynamic photolithographic mask. The system consists of eight elements: a UV laser light source, an optical shutter, beam-conditioning optics, a SLM, a multielement reduction lens system, a high-resolution translation stage, a control system, and a computer-aided-design system. Each of these system components is briefly described. In addition, the optical characteristics of commercially available UV curable resins are investigated with nondegenerate four-wave mixing. Holographic gratings were written at a wavelength of 351.1 nm and read at 632.8 nm to compare the reactivity, curing speed, shrinkage, and resolution of the resins. These experiments were carried out to prove the suitability of these photopolymerization systems for microstereolithography.
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Blaya S, Carretero L, Mallavia R, Fimia A, Madrigal RF, Ulibarrena M, Levy D. Optimization of an acrylamide-based dry film used for holographic recording. APPLIED OPTICS 1998; 37:7604-7610. [PMID: 18301597 DOI: 10.1364/ao.37.007604] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A study of the optimization and the characteristics of a dry film photopolymerizable recording material is presented. The effects of intensity, the thickness, and the variation of the concentration of each component have been studied. Diffraction efficiencies of 80%, with energetic sensitivities of 40 mJ/cm(2), have been obtained in photosensitive films of a 35-mum thickness with a spatial frequency of 1000 lines/mm.
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21
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Hu S, Popielarz R, Neckers DC. Fluorescence Probe Techniques (FPT) for Measuring the Relative Efficiencies of Free-Radical Photoinitiators. Macromolecules 1998. [DOI: 10.1021/ma971390l] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shengkui Hu
- Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, and Spectra Group Limited, Inc., 1722 Indianwood Circle, Suite H, Maumee, Ohio 43537
| | - Roman Popielarz
- Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, and Spectra Group Limited, Inc., 1722 Indianwood Circle, Suite H, Maumee, Ohio 43537
| | - Douglas C. Neckers
- Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, and Spectra Group Limited, Inc., 1722 Indianwood Circle, Suite H, Maumee, Ohio 43537
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Farsari M, Huang S, Young R, Heywood M, Morrell P, Chatwin C. Four-wave mixing studies of UV curable resins for microstereolithography. J Photochem Photobiol A Chem 1998. [DOI: 10.1016/s1010-6030(98)00242-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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23
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Jordan OP, Marquis-Weible F. Characterization of photopolymerization by a holographic technique applied to a scattering hydrogel. APPLIED OPTICS 1996; 35:6146-50. [PMID: 21127633 PMCID: PMC10335151 DOI: 10.1364/ao.35.006146] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 06/04/2023] [Accepted: 06/14/2023] [Indexed: 05/30/2023]
Abstract
A holographic technique, which consists of writing a phase grating onto a photopolymer layer and recording the time evolution of its diffraction efficiency, is presented for a scattering hydrogel. The influence of photopolymer thickness and writing laser intensity is investigated. Writing parameters that yield maximum diffraction efficiency are determined. A thickness greater than 1/3 of the scattering length results in the diffusion of light in the sample, leading to a decreased diffraction efficiency of the grating. This behavior can be explained by a combination of chemical diffusion and optical scattering. Finally, a calibration of diffraction efficiency with respect to a gel and sol fraction is presented.
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