Structural and dielectrical characterization of low-k polyurethane composite films with silica aerogel

Bozoglu, Deniz; Deligöz, Hüseyin; Yakut, Şahin; Deǧer, D.

doi:10.1016/j.jpcs.2019.02.013

Cited by 26 publications

(17 citation statements)

References 49 publications

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“…ω is the angular frequency, τ is the relaxation time, and β is the broadening coefficient of the polarization mechanism 23,30,31 . Electric modulus is mathematically the opposite of the dielectric function, as shown below 21,27,32 :

M^{'} + i M^{''} = \frac{1}{ε_{normalr}^{'} - i ε_{normalr}^{''}},

M^{'} = \frac{ε_{r}^{'}}{ε_{normalr}^{' 2} + ε_{normalr}^{″ 2}}, M^{''} = \frac{ε_{r}^{″}}{ε_{normalr}^{' 2} + ε_{normalr}^{″ 2}},

where M′ is a real part of the electric modulus, and M ″ is the imaginary part of the electric modulus. But, hereafter, M ″ will be named as electric modulus.…”

Section: Methodsmentioning

confidence: 99%

“…But, hereafter, M ″ will be named as electric modulus. Vogel–Fulcher–Tamman (VFT) equation is below:

\ln f_{\max} = \ln f_{\infty} - (\frac{D T_{0}}{T - T_{0}}),

where f max is the peak frequency at which M ″ has a maximum value, f ∞ is the frequency at infinitely high temperatures, D is ductility, T is the temperature in Kelvin, and T 0 is Vogel temperature, which is different from glass transition temperature T g about 30–70 K 27,30–33 . The samples are thin films, and we want to determine the T g and ductility of thin films depending on film thickness.…”

Section: Methodsmentioning

confidence: 99%

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Thickness‐dependent glass transition temperature of hydroxyethyl cellulose thin films based on dielectric properties

Ulutas,

Yakut,

Bozoglu

et al. 2024

J of Applied Polymer Sci

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Hydroxyethyl cellulose (HEC) thin films with a molecular weight of 720,000 g/mol deposited by thermal evaporation in a thickness range of 250, 500, and 750 nm were measured in a frequency range of 1–105 Hz and a temperature range of 233–373 K for dielectric characterization with increments of 10 K. Dielectric results were used to derive and evaluate the glass transition temperature and ductility, which are essential parameters for structural analysis. Results showed that the thickness of HEC thin films was an effective parameter on dielectric and structural properties. Because of the increasing thickness, the dielectric constant has values between 22 and 143 at 1 kHz, and glass transition temperature and ductility change between 211–175 K and 15–20, respectively. Based on the literature and the compatible results, the main effect of these variations could be dead layers and voids in structure. The effect of the dead layer gave an important idea about the adjustability of mechanical properties of HEC thin films depending on the thickness. In this way, it would be possible to use these thin films deposited from HEC with 720,000 g/mol molecular weight, especially in drug delivery, electrophoresis technologies, biomedical devices, and coverage applications.

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M^{'} + i M^{''} = \frac{1}{ε_{normalr}^{'} - i ε_{normalr}^{''}},

M^{'} = \frac{ε_{r}^{'}}{ε_{normalr}^{' 2} + ε_{normalr}^{″ 2}}, M^{''} = \frac{ε_{r}^{″}}{ε_{normalr}^{' 2} + ε_{normalr}^{″ 2}},

where M′ is a real part of the electric modulus, and M ″ is the imaginary part of the electric modulus. But, hereafter, M ″ will be named as electric modulus.…”

Section: Methodsmentioning

confidence: 99%

“…But, hereafter, M ″ will be named as electric modulus. Vogel–Fulcher–Tamman (VFT) equation is below:

\ln f_{\max} = \ln f_{\infty} - (\frac{D T_{0}}{T - T_{0}}),

Section: Methodsmentioning

confidence: 99%

Thickness‐dependent glass transition temperature of hydroxyethyl cellulose thin films based on dielectric properties

Ulutas,

Yakut,

Bozoglu

et al. 2024

J of Applied Polymer Sci

Self Cite

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show abstract

“…This behavior was also noticed with the MPLA/SA composites and increased with increasing SA concentration. Thus, water resistance can be increased by adding SA to PLA or MPLA-based composites [39,40]. Moreover, at the same SA loading, composites containing PLA/SA had contact angles that were about 4.0-5.5°( 0.6 wt%) or 7.0-8.0° (1.2 wt%) lower than the contact angles of composites containing MPLA/SA.…”

Section: Tensile Properties and Surface Wettabilitymentioning

confidence: 99%

Heat-regulating polylactic acid/silica aerogel composite fabric: Preparation and characterization

Wu¹,

Wu²,

Wang³

2022

Express Polym. Lett.

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“…Air has low dielectric constant and dielectric loss of 1.01 and 0, respectively. Incorporation of porous fillers, such as hollow glass microsphere, [ 140 ] mesoporous organosilica, [ 141 ] polyhedral oligomeric silsesquioxane (POSS), [ 78,142 ] and silica aerogel [ 143 ] into the polymer matrix has been proven as an effective method for reducing the dielectric constant. However, owing to the low thermal conductivity of air (0.026 W m −1 K −1 ), these porous fillers with air voids do not give high thermal conductivity enhancement for the final composites.…”

Section: Other Required Properties For High‐performance Underfill Mat...mentioning

confidence: 99%

Advances on Thermally Conductive Epoxy‐Based Composites as Electronic Packaging Underfill Materials—A Review

Wen

Chen

et al. 2022

Advanced Materials

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The integrated circuits industry has been continuously producing microelectronic components with ever higher integration level, packaging density, and power density, which demand more stringent requirements for heat dissipation. Electronic packaging materials are used to pack these microelectronic components together, help to dissipate heat, redistribute stresses, and protect the whole system from the environment. They serve an important role in ensuring the performance and reliability of the electronic devices. Among various packaging materials, epoxy‐based underfills are often employed in flip‐chip packaging. However, widely used capillary underfill materials suffer from their low thermal conductivity, unable to meet the growing heat dissipation required of next‐generation IC chips with much higher power density. Many strategies have been proposed to improve the thermal conductivity of epoxy, but its application as underfill materials with complex performance requirements is still difficult. In fact, optimizing the combined thermal–electrical–mechanical–processing properties of underfill materials for flip‐chip packaging remains a great challenge. Herein, state‐of‐the‐art advances that have been made to satisfy the key requirements of capillary underfill materials are reviewed. Based on these studies, the perspectives for designing high‐performance underfill materials with novel microstructures in electronic packaging for high‐power density electronic devices are provided.

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Structural and dielectrical characterization of low-k polyurethane composite films with silica aerogel

Cited by 26 publications

References 49 publications

Thickness‐dependent glass transition temperature of hydroxyethyl cellulose thin films based on dielectric properties

Thickness‐dependent glass transition temperature of hydroxyethyl cellulose thin films based on dielectric properties

Heat-regulating polylactic acid/silica aerogel composite fabric: Preparation and characterization

Advances on Thermally Conductive Epoxy‐Based Composites as Electronic Packaging Underfill Materials—A Review

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