scholarly journals Using microprojectiles to study the ballistic limit of polymer thin films

Soft Matter ◽  
2020 ◽  
Vol 16 (16) ◽  
pp. 3886-3890 ◽  
Author(s):  
Shawn H. Chen ◽  
Amanda J. Souna ◽  
Christopher L. Soles ◽  
Stephan J. Stranick ◽  
Edwin P. Chan

In this work, a microballistic impact test called laser induced projectile impact test (LIPIT) was used to study the perforation behavior of polycarbonate thin films to demonstrate the importance of film thickness on the film's ballistic limit.

2005 ◽  
Vol 890 ◽  
Author(s):  
Chunhua Li ◽  
Jun Jiang ◽  
Miriam J. Rafailovich ◽  
Jonathan C. Sokolov

ABSTRACTPreviously, we reported that the viscosity of a polymer film can be measured in situ by observing the liquid-liquid dewetting of polymer bilayer films. In this study, we use the technique to investigate the effect of film thickness and surface interactions on the effective viscosity of polymer thin films. We found that the effective viscosity increases dramatically with decreasing the film thickness. We attribute this to the pinning of the polymer chains at the strongly interacting polymer/Silicon interface.


2018 ◽  
Vol 21 (8) ◽  
pp. 817-824 ◽  
Author(s):  
Jinho Hyon ◽  
Olawale Lawal ◽  
Omri Fried ◽  
Ramathasan Thevamaran ◽  
Sadegh Yazdi ◽  
...  

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1621
Author(s):  
Mujib Ur Rahman ◽  
Yonghao Xi ◽  
Haipeng Li ◽  
Fei Chen ◽  
Dongjie Liu ◽  
...  

The stability/instability behavior of polystyrene (PS) films with tunable thickness ranging from higher as-cast to lower residual made on Si substrates with and without native oxide layer was studied in this paper. For further extraction of residual PS thin film (hresi) and to investigate the polymer–substrate interaction, Guiselin’s method was used by decomposing the polymer thin films in different solvents. The solvents for removing loosely adsorbed chains and extracting the strongly adsorbed irreversible chains were selected based on their relative desorption energy difference with polymer. The PS thin films rinsed in chloroform with higher polarity than that of toluene showed a higher decrease in the residual film thickness but exhibited earlier growth of holes and dewetting in the film. The un-annealed samples with a higher oxide film thickness showed a higher decrease in the PS residual film thickness. The effective viscosity of PS thin films spin-coated on H-Si substrates increased because of more resistance to flow dynamics due to the stronger polymer–substrate interaction as compared to that of Si-SiOx substrates. By decreasing the film thickness, the overall effective mobility of the film increased and led to the decrease in the effective viscosity, with matching results of the film morphology from atomic force microscopy (AFM). The polymer film maintained low viscosity until a certain period of time, whereupon further annealing occurred, and the formation of holes in the film grew, which ultimately dewetted the film. The residual film decrement, growth of holes in the film, and dewetting of the polymer-confined thin film showed dependence on the effective viscosity, the strength of solvent used, and various involved interactions on the surface of substrates.


2021 ◽  
Vol 3 ◽  
Author(s):  
Stefan Spirk ◽  
Chonnipa Palasingh ◽  
Tiina Nypelö

Polymer thin films with thickness below 100 nm are a fascinating class of 2D materials with commercial and research applications in many branches ranging from coatings to photoresists and insulating materials, to mention just a few uses. Biopolymers have extended the scope of polymer thin films with unique materials such as cellulose, cellulose nanocrystals, cellulose nanofibrils with tunable water uptake, crystallinity and optical properties. The key information needed in thin biopolymer film use and research is film thickness. It is often challenging to determine precisely and hence several techniques and their combinations are used. Additional challenges with hydrophilic biopolymers such as cellulose are the presence of humidity and the soft and often heterogenous structure of the films. This minireview summarizes currently used methods and techniques for biopolymer thin film thickness analysis and outlines challenges for accurate and reproducible characterization. Cellulose is chosen as the representative biopolymer.


1998 ◽  
Vol 536 ◽  
Author(s):  
A. B. Pevtsov ◽  
N. A. Feoktistov ◽  
V. G. Golubev

AbstractThin (<1000 Å) hydrogenated nanocrystalline silicon films are widely used in solar cells, light emitting diodes, and spatial light modulators. In this work the conductivity of doped and undoped amorphous-nanocrystalline silicon thin films is studied as a function of film thickness: a giant anisotropy of conductivity is established. The longitudinal conductivity decreases dramatically (by a factor of 109 − 1010) as the layer thickness is reduced from 1500 Å to 200 Å, while the transverse conductivity remains close to that of a doped a- Si:H. The data obtained are interpreted in terms of the percolation theory.


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