Properties of Some Poly(siloxane)s for Optical Applications

Brunchi, Cristina‐Eliza; Filimon, Anca; Cazacu, Maria; Ioan, Silvia

doi:10.1177/0954008308088737

Cited by 19 publications

(5 citation statements)

References 18 publications

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“…A second possible explanation could be the cleavage of the methoxy and hydroxy groups during condensation. Both methyl and hydroxy groups should have a higher molar refraction than the Si–O–Si unit obtained by condensation . Interestingly, the RI of both oligosiloxanes containing the 2-naphthyl group increases after consolidation and for MGNaph2_Ph_Ph 2 even reaching the highest value of all samples.…”

Section: Results and Discussionmentioning

confidence: 88%

“…Both methyl and hydroxy groups should have a higher molar refraction than the Si−O−Si unit obtained by condensation. 92 Interestingly, the RI of both oligosiloxanes containing the 2naphthyl group increases after consolidation and for MGNaph2_Ph_Ph 2 even reaching the highest value of all samples. A definitive explanation for this observation cannot be given at this point.…”

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confidence: 86%

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High-Refractive-Index Polysiloxanes Containing Naphthyl and Phenanthrenyl Groups and Their Thermally Cross-Linked Resins

2022

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High-refractive-index polysiloxanes containing naphthyl, phenanthrenyl, phenyl, and methyl groups have been synthesized using a polycondensation reaction starting from substituted di- and trialkoxysilanes. The obtained polymers comprised linear siloxane and partially cross-linked silsesquioxane units and showed optical transparencies of up to 99% at a thickness around 120 μm and high refractive indices of up to 1.622. The polymeric structures contained stabilized silanol groups that were further cross-linked at increased temperatures of 200 °C resulting in the formation of hybrid inorganic–organic resins. These typical thermal treatments at 200 °C for 72 h kept the transparencies as high as 98% and slightly lowered the RIs to values up to 1.610. A detailed structure evaluation of the resulting systems showed, depending on the size of the polycyclic aromatic substituent, excimer formation, which is based on weak interactions of the aromatic groups in the polymeric material. After thermal consolidation, glass-transition temperatures of the cross-linked systems were in the range of 18–74 °C depending on the composition. Thermal stabilities of the final resins reached higher values than commonly used siloxane resins up to 470 °C. The final materials are potential resins for high-temperature optical applications.

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Section: Results and Discussionmentioning

confidence: 88%

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confidence: 86%

High-Refractive-Index Polysiloxanes Containing Naphthyl and Phenanthrenyl Groups and Their Thermally Cross-Linked Resins

2022

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“…Refractive index (RI) matching has been employed for commercial silicones but not yet examined in detail for formulations that are printable by direct ink writing. [33][34][35][36] For printable formulations of polysiloxanes, reinforcing fillers like fumed silica can be added to a polysiloxane base to provide thixotropy. The RI mismatch between fumed silica (RI ≈ 1.45) and polysiloxanes that are often used for printable formulations provide multiple scattering sites that render the cured material opaque.…”

Section: Introductionmentioning

confidence: 99%

3D Printing of Transparent Silicone Elastomers

Ford

Loeb

Pérez

et al. 2021

Adv Materials Technologies

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In this paper, inks for transparent elastomers that are formulated by matching the refractive index of silica and polysiloxanes are described. The transparent inks transmit up to ≈90% of 700 nm light through 1 cm and remain transparent when solidified. The inks and solidified materials exhibit a thermochromic effect. This thermochromic effect can be controlled by the refractive index mismatch. Transparency may increase or decrease as temperature increases, depending on the refractive index mismatch of the base polysiloxane and silica. It is found that the rheological properties of the ink depend on the distribution of silica particles, which is dictated by silica functionality, weight content, and processing. Siloxane precursors that vary in chemical functionality are introduced to tailor the mechanical properties of the printed elastomers, which obtain stretchability >65% along with a tensile modulus of 1.9 MPa. After optimizing siloxane chemistry and ink processing, the authors are able to print transparent elastomers. Potential applications are demonstrated for printed structures by printing encapsulation structures for light‐emitting diodes, semitransparent dye‐filled structures, a microfluidic mixing device, and a multimaterial structure that exhibits temperature‐dependent camouflage.

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“…Silicone polymers containing diphenylsiloxane groups and a refractive index of 1.43−1.46 are useful in bio-optic applications in obtaining a thin lens (e.g., intraocular lenses). The diphenylsiloxane units have a marked anisotropy of polarizability increasing the optical sensitivity of siloxane polymers. , …”

Section: Introductionmentioning

confidence: 99%

“…The diphenylsiloxane units have a marked anisotropy of polarizability increasing the optical sensitivity of siloxane polymers. 21,22 Motivated by the fundamental and practical considerations outlined above, in this work we investigate the effect of the solvent quality on the thermodynamic behavior of the polydimethyldiphenylsiloxane copolymer by using turbidimetry and viscosimetry.…”

Section: Introductionmentioning

confidence: 99%

Influence of the Solvent Quality on the Thermodynamic Behavior of Polymethylphenylsiloxane Solutions

Brunchi¹,

Morariu²,

Cazacu³

et al. 2010

Ind. Eng. Chem. Res.

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In this work we investigate the effect of the solvent quality on the thermodynamic behavior of the polydimethyldiphenylsiloxane copolymer by using turbidimetry and viscosimetry. The turbidimetric method was used for the determination of the composition of the solvent mixture at the theta point. The experimental data obtained by using the capillary viscometry both in good and theta solvent conditions have been processed by using classical Huggins equation and new Wolf model ( 2007), which allows the calculation of intrinsic viscosities and other hydrodynamic parameters. The results obtained by using the two approaches were discussed comparatively. The conformational properties of copolymer in solution depend on their molecular structure, which is essentially dominated by the solvent quality, reflecting the balance of the interactions between the polymer chains and each solvent and that between solvent molecules.

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Properties of Some Poly(siloxane)s for Optical Applications

Cited by 19 publications

References 18 publications

High-Refractive-Index Polysiloxanes Containing Naphthyl and Phenanthrenyl Groups and Their Thermally Cross-Linked Resins

High-Refractive-Index Polysiloxanes Containing Naphthyl and Phenanthrenyl Groups and Their Thermally Cross-Linked Resins

3D Printing of Transparent Silicone Elastomers

Influence of the Solvent Quality on the Thermodynamic Behavior of Polymethylphenylsiloxane Solutions

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