Surface buckling delamination patterns of film on soft spherical substrates

Soft Matter ◽  
2020 ◽  
Vol 16 (16) ◽  
pp. 3952-3961
Author(s):  
Kanako Emori ◽  
Yusaku Saito ◽  
Akio Yonezu ◽  
Liangliang Zhu ◽  
Xiangbiao Liao ◽  
...  

The morphological transition of film buckling-delamination in an elastomeric bilayer spherical shell system was studied experimentally and numerically. It was changed by the film thickness, Young's modulus, and interfacial adhesion condition, etc.

2014 ◽  
Vol 1752 ◽  
pp. 59-63
Author(s):  
Junyoung Lim ◽  
Maryam Jalali ◽  
Stephen A. Campbell

ABSTRACTElectrophoretic deposition enables the rapid deposition of single wall carbon nanotube films at room temperature. An accurate, reproducible film thickness can be obtained by controlling electric field strength, suspension concentration, and time. To investigate the electrical and mechanical properties of such films, we recorded electric resistance and Young’s modulus using I-V characterization and a nanoindenter, respectively. The measured resistivity of the films varied from 2.14 × 10-3 to 7.66 × 10-3 Ω·cm, and the Young’s modulus was 4.72 to 5.67 GPa, independent of film thickness from 77 to 134 nm. These results indicated that the mechanical and electrical properties of film are comparable with previously reported methods such as layer by layer deposition even though we achieved much higher deposition rates. We also measured the film mass density which is usually unrecorded even though it is an important parameter for MEMS/NEMS device actuation. The film density was found with conventional thickness measurement and Rutherford backscattering spectrometry. It varied from 0.12 to 0.54 g/cm3 as the film thickness increased. This method could be extended to applications of CNT films for flexible electronics or high frequency RF MEMS devices.


2020 ◽  
Vol 27 ◽  
pp. 57-61
Author(s):  
Radim Kudělka ◽  
Lukáš Václavek ◽  
Jan Tomáštík ◽  
Sabina Malecová ◽  
Radim Čtvrtlík

Knowledge of mechanical properties of thin films is essential for most of their applications. However, their determination can be problematic for very thin films. LAW (Laser-induced acoustic waves) is a combined acousto-optic method capable of measuring films with thickness from few nanometers. It utilizes ultrasound surface waves which are excited via short laser pulses and detected by a PVDF foil. Properties such as Young’s modulus, Poisson’s ratio and density of both the film and the substrate as well as film thickness can be explored.Results from the LAW method are successfully compared with nanoindentation for Young’s modulus evaluation and with optical method for film thickness evaluation and also with literature data. Application of LAW for anisotropy mapping of materials with cubic crystallographic lattice is also demonstrated.


Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3538 ◽  
Author(s):  
Karolina Mazur ◽  
Stanisław Kuciel

Biodegradable composites based on poly (3-hydroxybutyrate-co-3-hydroxyvalerate), reinforced with 7.5% or 15% by weight of wood fibers (WF) or basalt fibers (BF) were fabricated by injection molding. BF reinforced composites showed improvement in all properties, whereas WF composites showed an increase in Young’s modulus values, but a drop in strength and impact properties. When compared with the unmodified polymer, composites with 15% by weight of BF showed an increase of 74% in Young’s modulus and 41% in impact strength. Furthermore, the experimentally measured values of Young’s modulus were compared with values obtained in various theoretical micromechanical models. The Haplin-Kardas model was found to be in near approximation to the experimental data. The morphological aspect of the biocomposites was studied using scanning electron microscopy to obtain the distribution and interfacial adhesion of the fibers. Additionally, biodegradation tests of the biocomposites were performed in saline solution at 40 °C by studying the weight loss and mechanical properties. It was observed that the presence of fibers affects the rate of water absorption and the highest rate was seen for composites with 15% by weight of WF. This is dependent on the nature of the fiber. After both the first and second weeks mechanical properties decreased slightly about 10%.


2019 ◽  
Vol 947 ◽  
pp. 200-204
Author(s):  
Sirirat Wacharawichanant ◽  
Patteera Opasakornwong ◽  
Ratchadakorn Poohoi ◽  
Manop Phankokkruad

This work studied the improvement of poly (lactic acid) (PLA) properties by adding propylene-ethylene copolymer (PEC) and α-cellulose (AC). The PLA blends and composites were melt mixed by an internal mixer and molded by compression method. The morphological analysis observed the phase separation of PLA/PEC blends due to minor PEC phase dispersed as spherical shape in PLA phase, indicating a poor interfacial adhesion between PLA and PEC phases. The incorporation of AC did not improve the compatibility of polymer blends. Young’s modulus and tensile strength of PLA blends reduced with increasing amount of PEC because the elastics of ethylene molecules in PEC structure. Young’s modulus of PLA/PEC/AC composites increased with increasing AC contents. The stress at break of the PLA/PEC blends was improved with the presence of AC. The strain at break of PLA/PEC blends increased with increasing PEC contents, and the presence of AC showed the decrease of strain at break of PLA/PEC blends.


2006 ◽  
Vol 45 (5) ◽  
pp. 597-600 ◽  
Author(s):  
P. A. Mahanwar ◽  
Suryasarathi Bose ◽  
Abhishek Venkatesh Tirumalai

2011 ◽  
Vol 410 ◽  
pp. 51-54 ◽  
Author(s):  
Arpaporn Teamsinsungvon ◽  
Yupaporn Ruksakulpiwat ◽  
Kasama Jarukumjorn

Poly (lactic acid) (PLA)/poly (butylene adipate-co-terephthalate) (PBAT) blend and its composite were prepared by melt blending method. Maleic anhydride grafted PLA (PLA-g-MA) prepared in-house was used as a compatibilizer to enhance the interfacial adhesion between PLA and PBAT and also to improve the dispersion of calcium carbonate (CaCO3) in polymer matrices. Increasing PBAT content (10-30 wt%) resulted in the improvement of elongation at break and impact strength of PLA. Tensile strength, Young’s modulus, and impact strength of PLA/PBAT blend improved with the presence of PLA-g-MA due to enhanced interfacial adhesion between PLA and PBAT. As CaCO3 (5 wt%) was incorporated into the compatibilized blend, tensile strength, Young’s modulus, and impact strength insignificantly changed while elongation at break decreased.


2001 ◽  
Vol 695 ◽  
Author(s):  
Yong Xiang ◽  
Xi Chen ◽  
Joost J. Vlassak

ABSTRACTThe mechanical properties of freestanding electroplated Cu films were determined by measuring the deflection of Si-framed, pressurized membranes. The films were deformed under plane-strain conditions. The pressure-deflection data are converted into stress-strain curves by means of simple analytical formulae. The microstructure of the Cu films was characterized using scanning electron microscopy and x-ray diffraction. The yield stress, Young's modulus, and residual stress were determined as a function of film thickness and microstructure. Both yield stress and Young's modulus increase with decreasing film thickness and correlate well with changes in the microstructure and texture of the films.


2000 ◽  
Vol 122 (4) ◽  
pp. 721-724 ◽  
Author(s):  
T. Sperrfechter ◽  
R. Haller

The present work focuses on the investigation of the influence of bulk ceramic materials on the behavior of elastohydrodynamically (EHD) lubricated line contacts. The materials alumina Al2O3, zirconium oxide ZrO2 and aluminum nitride (AIN) are used. Comparative measurements were taken with steel disks made of 42CrMo4. Of primary importance are the material parameters Young’s modulus and thermal conductivity. The experimental variables pressure, temperature and oil film thickness in the EHD contact of a two disk test rig were measured with the aid of evaporated thin film sensors. As the results show, an increase in the Young’s modulus causes a clear increase of the pressure level. The oil film thickness distributions show a decline of the flattening width and of the constriction occurring at the contact outlet. The influence of the material with respect to its thermal conductivity dominates, above all, in the region of the load transmitting contact zone. The transition from a good to a bad conductor of heat causes a rise in temperature, more prominent for materials with lower thermal conductivities. This leads to viscosity decrease causing clearly reduced oil film thicknesses in the contact. [S0742-4787(00)01404-1]


Sensors ◽  
2021 ◽  
Vol 21 (20) ◽  
pp. 6779
Author(s):  
Rymantas Jonas Kažys ◽  
Olgirdas Tumšys

Ultrasonic guided waves are already used for material characterization. The advantage of these waves is that they propagate in the plane of a plate and their propagation characteristics are sensitive to properties of the material. The objective of this research was to develop an ultrasonic method that could be used to measure the properties of thin plastic polyvinylchloride films (PVC). The proposed method exploits two fundamental Lamb wave modes, A0 and S0, for measurement of a thin film thickness and Young’s modulus. The Young’s modulus is found from the measured phased velocity of the S0 mode and the film thickness from the velocities of both A0 and S0 modes. By using the proposed semi-contactless measurement algorithm, the Young’s modulus and thickness of different thickness (150 µm and 200 µm) PVC films were measured. The uncertainty of thickness measurements of the thinner 150 µm PVC film is 2% and the thicker 200 µm PVC film is 3.9%.


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