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Thermoplasmonica??Activated Hydrogel Based Dynamic Light Attenuator
摘要： This work describes the morphological, optical, and thermo-optical properties of a temperature-sensitive hydrogel poly(N-isopropylacrylamide-co-N-isopropylmethacrylamide) [P(NIPAm-co-NIPMAm]) film containing a specific amount of gold nanorods (GNRs). The light-induced thermoplasmonic heating of GNRs is used to control the optical scattering of an initially transparent hydrogel film. A hydrated P(NIPAm-co-NIPMAm) film is optically clear at room temperature. When heated to temperatures over 37 °C via light irradiation with a resonant source (λ = 810 nm) to the GNRs, a reversible phase transition from a swollen hydrated state to a shrunken dehydrated state occurs. This phenomenon causes a drastic and reversible change in the optical transparency from a clear to an opaque state. A significant red shift (≈30 nm) of the longitudinal band can also be seen due to an increased average refractive index surrounding the GNRs. This change is in agreement with an ad hoc theoretical model which uses a modified Gans theory for ellipsoidal nanoparticles. Morphological analysis of the composite film shows the presence of well-isolated and randomly dispersed GNRs. Thermo-optical experiments demonstrate an all-optically controlled light attenuator (65% contrast ratio) which can be easily integrated in several modern optical applications such as smart windows and light-responsive optical attenuators.
关键词： gold nanorods,active plasmonics,optical attenuators,polymers,optical transparency,hydrogels,plasmonic nanoparticles
更新于2025-09-23 15:19:57
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Towards solution-processable, thermally robust, transparent polyimide-chain-end tethered organosilicate nanohybrids
摘要： The main challenge to developing future display substrates is to synthesize flexible substrate materials that also have excellent optical and thermal properties, and low thermal expansion number. In this study, a novel trifluoromethylated asymmetric aromatic diamine, 4-[[4-(4-amino-2-trifluoromethylphenoxy)phenyl]sulfonyl-3-(trifluoromethyl)]benzenamine (AFPSFB), was synthesized through nucleophilic substitution. Conventional two-step polycondensation of AFPSFB with commercially available tetracarboxylic dianhydrides enabled the fabrication of fully or semi-aromatic polyimides (PIs). The resulting PIs were highly soluble in polar aprotic solvents with good optical and thermal properties. Next, polyhedral oligomeric silsesquioxane containing an amine group (NH2-POSS) was reacted with the resulting soluble PI. All the PI-POSS nanohybrids displayed excellent optical properties, including high transparency (> 91% at 400 nm), low refractive index (< 1.5589), and very small birefringence (< 0.0025 at 637 nm). End-capping of the POSS and chemical bonding between the POSS and PIs significantly enhanced the thermal and electrical properties. The results provide useful information for designing molecular architectures for manufacturing high-performance flexible substrates in future display devices.
关键词： Organosilicate,Optical transparency,Dielectric constant,Thermal stability,Soluble polyimide
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Chengdu, China (2018.3.26-2018.3.28)] 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Manipulating Propagation and Scattering of Microwave by Optically Transparent Metasurface
摘要： In this paper, metasurfaces with optical transparency is proposed to control either the propagation or the scattering of microwave. Specifically, we have designed a band-pass frequency selective surface (FSS) with a transmission window around 1.6 GHz and a coding metasurface for suppressing the backward scattering with broad working band from 7.8 to 15 GHz. The proposals provide new opportunities to tailor the microwave propagation and scattering with simultaneously high transmittance in visible frequencies, which could offer many benefits in practical uses, such as window and solar panel applications.
关键词： metasurface,microwave,optical transparency,FSS
更新于2025-09-10 09:29:36
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Organosoluble and transparent cardo polyimides with high <i>T</i> <sub/>g</sub> derived from 9,9-bis(4-aminophenyl)xanthene
摘要： 9,9-Bis(4-aminophenyl)xanthene (BAPX) was prepared simply and effectively via one-pot, two-step procedure using xanthenone and aniline as main substrates. The monomer BAPX was reacted with six aromatic dianhydrides in N,N-dimethylacetamide (DMAc) to yield the corresponding polyimides (PIs) via the poly(amic acid) precursors and subsequent thermal or chemical imidization. The resulting PIs exhibited good thermal stability with glass transition temperatures of 308–348°C, initial decomposition temperatures of 470–510°C, 10% weight loss temperatures of 540–565°C, and char yields of 55–59% at 800°C in nitrogen, respectively. All polymers were amorphous and readily soluble in organic solvents such as N-methyl-2-pyrrolidone and DMAc. The PI films had tensile strengths of 71–92 MPa, tensile moduli of 1.91–2.35 GPa, and elongations at break of 5–13%. Meanwhile, these polymer films also had high optical transparency with a cutoff wavelength in the range of 367–415 nm, lower dielectric constants (3.02–3.34 at 10 MHz), and low water uptake of 0.30–0.52%.
关键词： Aromatic polyimide,9,9-bis(4-aminophenyl)xanthene,bulky pendent xanthene cardo group,thermal property,optical transparency,solubility
更新于2025-09-04 15:30:14