Heterogeneous Lamellar Structures Near the Polymer/Substrate Interface

2012 ◽  
Vol 45 (17) ◽  
pp. 7098-7106 ◽  
Author(s):  
M. Asada ◽  
N. Jiang ◽  
L. Sendogdular ◽  
P. Gin ◽  
Y. Wang ◽  
...  
Keyword(s):  
Polymer Substrate ◽  
Substrate Interface ◽  
Lamellar Structures

Quantification of Interactions at the Polymer–Substrate Interface: Implications for Nanoscale Behavior

2021 ◽  
Author(s):  
J. K. Wenderott ◽  
Ban Xuan Dong ◽  
Jojo A. Amonoo ◽  
Peter F. Green
Keyword(s):  
Polymer Substrate ◽  
Substrate Interface

Glass transition behaviour of thin polymer films coated on the 3D networks of porous CNT sponges

2020 ◽  
Vol 22 (37) ◽  
pp. 21297-21306
Author(s):  
Min Wang ◽  
Jiapeng Zhang ◽  
Shenglin Zhou ◽  
Zhaohui Yang ◽  
Xiaohua Zhang
Keyword(s):  
Glass Transition ◽  
Free Surface ◽  
Polymer Films ◽  
Polymer Chains ◽  
Polymer Substrate ◽  
Thin Polymer Films ◽  
Substrate Interface ◽  
Thin Polymer ◽  
Transition Behaviour ◽  
3D Networks

The influence of the coexistence of a free surface and a polymer–substrate interface on the glass transition behaviour of polymer chains on CNT sidewalls.

Dynamic Control of Water Concentration to Prolong The Life Time of Encapsulated Electronic Devices in High Humidity Environments

1989 ◽  
Vol 154 ◽  
Author(s):  
I. U. Kim ◽  
P. R. Troyk ◽  
J. E. Anderson
Keyword(s):  
Chemical Potential ◽  
Multilayer Coating ◽  
Water Concentration ◽  
Saturated Solution ◽  
Polymer Substrate ◽  
Interesting Phenomenon ◽  
Substrate Interface ◽  
Substrate Structure ◽  
Group I ◽  
Group Ii

AbstractSilicone resins and gels have been used extensively for IC protection. Reduction of interfacial moisture and ionic contamination is considered crucial to device reliability.The present research has revealed an interesting phenomenon. Prolonged lifetime was obtained for comb pattern samples using a non-conventional encapsulation method. In order to increase specimen sensitivity to interfacial moisture, samples were contaminated prior to encapsulation. Three groups of contaminated samples encapsulated with polysiloxane were produced. Group I was encapsulated with a polymer/CaCl2/polymer/substrate structure. The structure of group II consisted of only the polymer on the contaminated substrates. Group III was encapsulated with a CaCl2 embedded polymer/polymer /substrate structure. Following exposure at 85°C, 100−10 amperes after 2,000 hrs, with no visible corrosion. Group II and III samples showed visible corrosipn after 390 to 470 hrs with leakage current of the order of 10−5 amperes. Direct measurement of RH at the polymer/substrate interface and water sorption experiments were done to explain the mechanisms of these packaging structures.The experimental results suggest that a desiccating multilayer coating can maintain low interfacial water concentrations. During exposure to high external RH, water from the surroundings diffuses through the top layer, producing an interlayer consisting of a solid CaCl2 and a CaCl2-saturated solution. Until all of the salt dissolves, the water chemical potential of the saturated solution defines the water content at the polymer/substrate interface. Hence the RH at the polymer/substrate interface was maintained below that required to dissolve the residual surface contamination for a longer time than by conventional encapsulation. This technique could be useful to reduce the dependence of IC reliability upon pre-encapsulation cleaning.

Shear-Induced Crystallization at Polymer–Substrate Interface: The Slippage Hypothesis

2011 ◽  
Vol 44 (17) ◽  
pp. 6919-6927 ◽  
Author(s):  
Bo Shen ◽  
Yongri Liang ◽  
Chenggui Zhang ◽  
Charles C. Han
Keyword(s):  
Polymer Substrate ◽  
Substrate Interface ◽  
Induced Crystallization

SEM/FESEM imaging of lamellar structures in melt extruded polyethylene films

1992 ◽  
Vol 50 (2) ◽  
pp. 1142-1143
Author(s):  
R.T. Chen ◽  
M.G. Jamieson ◽  
R. Callahan
Keyword(s):  
Imaging Techniques ◽  
Membrane Surface ◽  
High Stress ◽  
Extrusion Direction ◽  
Polymeric Membranes ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Crystalline Polymers ◽  
Lamellar Structures ◽  
Resolution Imaging

“Row lamellar” structures have previously been observed when highly crystalline polymers are melt-extruded and recrystallized under high stress. With annealing to perfect the stacked lamellar superstructure and subsequent stretching in the machine (extrusion) direction, slit-like micropores form between the stacked lamellae. This process has been adopted to produce polymeric membranes on a commercial scale with controlled microporous structures. In order to produce the desired pore morphology, row lamellar structures must be established in the membrane precursors, i.e., as-extruded and annealed polymer films or hollow fibers. Due to the lack of pronounced surface topography, the lamellar structures have typically been investigated by replica-TEM, an indirect and time consuming procedure. Recently, with the availability of high resolution imaging techniques such as scanning tunneling microscopy (STM) and field emission scanning electron microscopy (FESEM), the microporous structures on the membrane surface as well as lamellar structures in the precursors can be directly examined.The materials investigated are Celgard® polyethylene (PE) flat sheet membranes and their film precursors, both as-extruded and annealed, made at different extrusion rates (E.R.).

Parallel Glide: A Fundamentally Different Type of Dislocation Motion in Ultrathin Metal Films

2003 ◽  
Vol 779 ◽  
Author(s):  
T. John Balk ◽  
Gerhard Dehm ◽  
Eduard Arzt
Keyword(s):  
Thermal Cycling ◽  
Grain Boundaries ◽  
Film Surface ◽  
Metal Films ◽  
Geometric Constraints ◽  
Film Stress ◽  
Diffusional Creep ◽  
Creep Model ◽  
Substrate Interface ◽  
Film Substrate

AbstractWhen confronted by severe geometric constraints, dislocations may respond in unforeseen ways. One example of such unexpected behavior is parallel glide in unpassivated, ultrathin (200 nm and thinner) metal films. This involves the glide of dislocations parallel to and very near the film/substrate interface, following their emission from grain boundaries. In situ transmission electron microscopy reveals that this mechanism dominates the thermomechanical behavior of ultrathin, unpassivated copper films. However, according to Schmid's law, the biaxial film stress that evolves during thermal cycling does not generate a resolved shear stress parallel to the film/substrate interface and therefore should not drive such motion. Instead, it is proposed that the observed dislocations are generated as a result of atomic diffusion into the grain boundaries. This provides experimental support for the constrained diffusional creep model of Gao et al.[1], in which they described the diffusional exchange of atoms between the unpassivated film surface and grain boundaries at high temperatures, a process that can locally relax the film stress near those boundaries. In the grains where it is observed, parallel glide can account for the plastic strain generated within a film during thermal cycling. One feature of this mechanism at the nanoscale is that, as grain size decreases, eventually a single dislocation suffices to mediate plasticity in an entire grain during thermal cycling. Parallel glide is a new example of the interactions between dislocations and the surface/interface, which are likely to increase in importance during the persistent miniaturization of thin film geometries.

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