scholarly journals Copolyamide-Imide Membrane with Low CTE and CME for Potential Space Optical Applications

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1001
Author(s):  
Jiajia Yin ◽  
Danbo Mao ◽  
Bin Fan
Keyword(s):  
Imaging System ◽  
Coefficient Of Thermal Expansion ◽  
Structure Design ◽  
Optical Telescope ◽  
Aromatic Polyimide ◽  
System Architectures ◽  
Moisture Expansion ◽  
Polyimide Membrane ◽  
Optical Applications ◽  
Coefficient Of Moisture Expansion

Polyimide diffractive membrane lens can be used in space optical telescope to reduce the size and mass of an imaging system. However, traditional commercial aromatic polyimide membrane is hard to meet the challenging requirements of dimensional stability and optical homogeneity for optical use. Based on molecular structure design and the optimization of fabrication process, the prepared copolyamide-imide membrane achieved the desired performance of membrane as an optical material. It showed a very low coefficient of thermal expansion (CTE), which is 0.95 ppm/°C over a temperature range of −150–100 °C and relatively low coefficient of moisture expansion (CME), which is only 13.30 ppm/% RH (0~90% RH). For the optical use, the prepared copolyamide-imide membrane (φ200 mm) achieved good thickness uniformity with wave-front error smaller than λ/30 (λ = 632 nm) in RMS (root mean square). Besides, it simultaneously meets the optical, thermal, and mechanical requirements for space telescope use. Copolyamide-imide membranes in this research with good comprehensive performance can be used as large aperture membrane optical system architectures.

Photo-Thermal Spectroscopic Imaging of MEMS Structures with Sub-Micron Spatial Resolution

2012 ◽  
Vol 1415 ◽  
Author(s):  
Robert Furstenberg ◽  
Christopher A. Kendziora ◽  
Michael R. Papantonakis ◽  
Viet Nguyen ◽  
R. A. McGill
Keyword(s):  
Spatial Resolution ◽  
Thermal Emission ◽  
Imaging System ◽  
Chemical Vapor ◽  
Sample Surface ◽  
Laser Wavelength ◽  
Ir Detector ◽  
Experimental Conditions ◽  
Emission Signal ◽  
Polyimide Membrane

ABSTRACTWe are developing a new non-contact and non-destructive imaging technique which requires no sample preparation and provides similar content information as FTIR or Raman spectroscopy while being immune to fluorescence and offers a potentially faster scan rate and/or higher spatial resolution. It utilizes photo-thermal heating of the sample with a quantum cascade laser (or other suitable infrared laser) and measuring the resulting increase in thermal emissions by either an infrared (IR) detector or a laser probe consisting of a visible laser reflected from the sample. The latter case allows for further increases in the spatial resolution from ∼10 μm to ∼1 μm or better, with suitable experimental conditions. Since the thermal emission signal is proportional to the absorption coefficient, by tuning the wavelength of the IR laser we can directly measure the IR spectrum of the sample. By raster scanning over the surface of the sample we can obtain maps of the chemical composition of the sample surface. We demonstrate this technique by imaging the surface of a micro-fabricated flow-through chemical vapor preconcentrator consisting of a silicon frame and a suspended-perforated polyimide membrane with a pair of platinum heater traces, coated with a custom sorbent polymer for selective sorption of analyte. We measure the spatial resolution of our photo-thermal imaging system as well as discuss the conditions under which the spatial resolution can be further increased from the far-field diffraction limited resolution given by the combination of the imaging optic and IR excitation laser wavelength.

Study on molecular weight cut-off performance of asymmetric aromatic polyimide membrane

1997 ◽  
Vol 123 (1) ◽  
pp. 143-147 ◽  
Author(s):  
H. Ohya ◽  
I. Okazaki ◽  
M. Aihara ◽  
S. Tanisho ◽  
Y. Negishi
Keyword(s):  
Molecular Weight ◽  
Aromatic Polyimide ◽  
Polyimide Membrane

scholarly journals The aromatic polyimide membrane for gas separation and its applications.

1988 ◽  
Vol 67 (12) ◽  
pp. 1038-1051 ◽  
Author(s):  
Asumaru NAKAMURA ◽  
Minoru HOTTA ◽  
Kohei NINOMIYA
Keyword(s):  
Gas Separation ◽  
Aromatic Polyimide ◽  
Polyimide Membrane

Preparation of solution-processable colorless polyamide-imides with extremely low thermal expansion coefficients through an in-situ silylation method for potential space optical applications

e-Polymers ◽  
2016 ◽  
Vol 16 (5) ◽  
pp. 395-402 ◽  
Author(s):  
Song Wang ◽  
Guangjie Yang ◽  
Shibin Wu ◽  
Ge Ren ◽  
Wei Yang ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Linear Chain ◽  
Tensile Modulus ◽  
Optical Homogeneity ◽  
One Pot ◽  
System Architectures ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion

AbstractSeveral tough and flexible fluorinated polyamide-imide films were prepared from trimellitic anhydride chloride and 2,2′-bis(trifluoromethyl)benzidine through a facile one-pot in-situ silylation method. By incorporating fluorinated side groups, the solubility of the prepared polyamide-imide was greatly enhanced. Meanwhile, due to their linear chain configuration and the existence of hydrogen bonding, the prepared polyamide-imide films revealed high tensile strength, high tensile modulus, high glass transition temperature (Tg) and most interestingly, very low coefficient of thermal expansion (CTE) of 11 ppm/°C. Copolymerization with pyromellitic dianhydride (PMDA) led to an extremely low CTE of 4 ppm/°C which should be among the lowest values available for soluble polyamide-imides. The optical homogeneity and stress homogeneity of the obtained polyamide-imide films were also tested. After non-contact with substance and thermal treatment at 300°C, they revealed a better optical homogeneity and stress homogeneity than that of the commercially available Kapton polyimide (PI) films, with a PV value of 0.915 λ and RMS value of 0.163 λ. Thus, these colorless and soluble polyamide-imide films simultaneously possessing promising optical imaging performance are good candidates as novel diffractive membrane optical system architectures.

Warpage Analysis of FBGA (Fine Ball Grid Array) Package by the Altered EMC (Epoxy Molding Compound) Filler Contents

2006 ◽  
Vol 306-308 ◽  
pp. 625-630 ◽  
Author(s):  
Yong Tae Park ◽  
Yoo Kyoung Whang ◽  
Joon Ki Hong ◽  
Kwang Yoo Byeon
Keyword(s):  
Numerical Analysis ◽  
Material Properties ◽  
Filler Content ◽  
Coefficient Of Thermal Expansion ◽  
Ball Grid Array ◽  
Structure Design ◽  
Actual Measurement ◽  
Molding Compound ◽  
Semiconductor Packaging ◽  
Adhesive Materials

In a semiconductor packaging process, the warpage greatly has influenced the reliability of the package as well as the workability. The strip warpage in FBGA package result from the structure of constitutes and the thermal mismatch by the mechanical or thermal properties such as CTE (Coefficient of Thermal Expansion) and Modulus of EMC, substrate, chip and adhesive materials. Therefore, the optimization of material properties and the package structure design has been needed by the numerical analysis. EMC used as one of the package constituents has a decisive effect on the trend of warpage, and the filler content is dominant in the EMC property. In this research, firstly the effect of the filler contents is evaluated in the warpage of FBGA package and the numerical analysis is performed with the high temperature – material properties to deal with the warpage under the actual measurement value.

Separation of alcohol aqueous solution by pervaporation using asymmetric polyimide membrane

1995 ◽  
Vol 7 (3) ◽  
pp. 275-281 ◽  
Author(s):  
H Yanagishita ◽  
D Kitamoto ◽  
T Nakane
Keyword(s):  
Aqueous Solution ◽  
Phase Inversion ◽  
Dimethyl Formamide ◽  
Inversion Process ◽  
Vacuum Oven ◽  
Aromatic Polyimide ◽  
Membrane Performance ◽  
Polyimide Membrane ◽  
Separation Factors ◽  
Phase Inversion Process

Asymmetric polyimide membranes were prepared by the phase inversion process by casting solutions composed of 25 wt% aromatic polyimide (PI-2080), 35 wt% N,N'-dimethyl formamide (DMF) and 40wt% dioxane. The membranes were annealed at 300C for 3 h in a vacuum oven and were measured for various alcohol aqueous solutions in pervaporation. The membrane exhibited separation factors of a(H20/EtOH) = 900 and a(H,0/2-PrOH)= I I000 with a flux of 0.45 kgm 2 h t for a 95 vol.% alcohol aqueous solution at 60C. The membrane showed stable membrane performance for 3 months for a 95 vol.% ethanol aqueous solution at 60"C.

scholarly journals Ultralong lifetime and efficient room temperature phosphorescent carbon dots through multi-confinement structure design

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuqiong Sun ◽  
Shuting Liu ◽  
Luyi Sun ◽  
Shuangshuang Wu ◽  
Guangqi Hu ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
Carbon Dots ◽  
Room Temperature ◽  
Structure Design ◽  
Room Temperature Phosphorescence ◽  
Long Lifetime ◽  
Optical Applications ◽  
Triplet Excited States ◽  
Exceptional Stability ◽  
Harsh Conditions

Abstract Room temperature phosphorescence materials have inspired extensive attention owing to their great potential in optical applications. However, it is hard to achieve a room temperature phosphorescence material with simultaneous long lifetime and high phosphorescence quantum efficiency. Herein, multi-confined carbon dots were designed and fabricated, enabling room temperature phosphorescence material with simultaneous ultralong lifetime, high phosphorescence quantum efficiency, and excellent stability. The multi-confinement by a highly rigid network, stable covalent bonding, and 3D spatial restriction efficiently rigidified the triplet excited states of carbon dots from non-radiative deactivation. The as-designed multi-confined carbon dots exhibit ultralong lifetime of 5.72 s, phosphorescence quantum efficiency of 26.36%, and exceptional stability against strong oxidants, acids and bases, as well as polar solvents. This work provides design principles and a universal strategy to construct metal-free room temperature phosphorescence materials with ultralong lifetime, high phosphorescence quantum efficiency, and high stability for promising applications, especially under harsh conditions.

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