scholarly journals Surface Segregation of Amphiphilic PDMS-Based Films Containing Terpolymers with Siloxane, Fluorinated and Ethoxylated Side Chains

Coatings ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 153 ◽  
Author(s):  
Elisa Martinelli ◽  
Elisa Guazzelli ◽  
Antonella Glisenti ◽  
Giancarlo Galli
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Segregation ◽  
Water Environment ◽  
Film Surface ◽  
Side Chain ◽  
Chemical Compositions ◽  
Side Chains ◽  
Air Interface ◽  
High Enrichment ◽  
Surface Active

(Meth)acrylic terpolymers carrying siloxane (Si), fluoroalkyl (F) and ethoxylated (EG) side chains were synthesized with comparable molar compositions and different lengths of the Si and EG side chains, while the length of the fluorinated side chain was kept constant. Such terpolymers were used as surface-active modifiers of polydimethylsiloxane (PDMS)-based films with a loading of 4 wt%. The surface chemical compositions of both the films and the pristine terpolymers were determined by angle-resolved X-ray photoelectron spectroscopy (AR-XPS) at different photoemission angles. The terpolymer was effectively segregated to the polymer−air interface of the films independent of the length of the constituent side chains. However, the specific details of the film surface modification depended upon the chemical structure of the terpolymer itself. The exceptionally high enrichment in F chains at the surface caused the accumulation of EG chains at the surface as well. The response of the films to the water environment was also proven to strictly depend on the type of terpolymer contained. While terpolymers with shorter EG chains appeared not to be affected by immersion in water for seven days, those containing longer EG chains underwent a massive surface reconstruction.

scholarly journals The Effect of Poly(ethylene glycol) (PEG) Length on the Wettability and Surface Chemistry of PEG-Fluoroalkyl-Modified Polystyrene Diblock Copolymers and Their Two-Layer Films with Elastomer Matrix

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1236 ◽  
Author(s):  
Elisa Guazzelli ◽  
Giancarlo Galli ◽  
Elisa Martinelli
Keyword(s):  
Diblock Copolymers ◽  
Film Surface ◽  
Dynamic Contact ◽  
Contact Angles ◽  
Side Chains ◽  
Water Contact ◽  
Prolonged Contact ◽  
High Enrichment ◽  
Poly Ethylene ◽  
Modified Polystyrene

Diblock copolymers composed of a polystyrene first block and a PEG-fluoroalkyl chain-modified polystyrene second block were synthesized by controlled atom transfer radical polymerization (ATRP), starting from the same polystyrene macroinitiator. The wettability of the polymer film surfaces was investigated by measurements of static and dynamic contact angles. An increase in advancing water contact angle was evident for all the films after immersion in water for short times (10 and 1000 s), consistent with an unusual contraphilic switch of the PEG-fluoroalkyl side chains. Such a contraphilic response also accounted for the retained wettability of the polymer films upon prolonged contact with water, without an anticipated increase in the hydrophilic character. The copolymers were then used as surface-active modifiers of elastomer poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS)-based two-layer films. The elastomeric behavior of the films was varied by using SEBS matrices with different amounts of polystyrene. Whereas the mechanical properties strictly resembled those of the nature of the SEBS matrix, the surface properties were imposed by the additive. The contraphilic switch of the PEG-fluoroalkyl side chains resulted in an exceptionally high enrichment in fluorine of the film surface after immersion in water for seven days.

Etching Characteristics of Low-k Dielectric Using C5H2F10 Liquefied Gas Plasma for Mitigating of Global Warming Potential

2021 ◽  
Vol 13 (9) ◽  
pp. 1764-1770
Author(s):  
Yeonsik Choi ◽  
Jongchan Lee ◽  
Younghun Oh ◽  
Hyun Woo Lee ◽  
Kwang-Ho Kwon
Keyword(s):  
Thin Film ◽  
Dielectric Constant ◽  
Plasma Etching ◽  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Film Surface ◽  
Chemical Compositions ◽  
Nanoscale Devices ◽  
Mixed Gas ◽  
Gas Plasma

In this work, we studied the etch characteristics and dielectric constant change of SiOC thin films by plasma etching for the fabrication of nanoscale devices to evaluate the C5H2F10 as alternative etching gas. We performed plasma etching of SiOC films with inductively coupled plasma using the CF4+X+O2 mixed gas, where X = CHF3 and C5H2F10. Plasma diagnosis such as optical emission spectroscopy and double Langmuir probe measurements were carried. We analyzed the chemical compositions of residues on the etched SiOC film surface using X-ray photoelectron spectroscopy. After the process, contact resistance was measured using the transmission line method to analyze the degree of polymer on the surface of the silicon. Ellipsometry were used to evaluate the change in the dielectric constant of the thin film due to plasma exposure. It was confirmed that the etched profile was more vertical than that of the CHF3 gas plasma, and the increase in the dielectric constant of the SiOC thin film by C5H2F10 gas plasma is less than that of CHF3 gas plasma. These results confirmed that C5H2F10 gas was a powerful alternative to CHF3 gas in semiconductor processing for the fabrication of nanoscale devices.

scholarly journals Temperature dependant structural changes in thin films of random semifluorinated PMMA copolymers

2013 ◽  
Vol 28 (S2) ◽  
pp. S144-S160 ◽  
Author(s):  
Dieter Jehnichen ◽  
Peter Friedel ◽  
Romy Selinger ◽  
Andreas Korwitz ◽  
Martin Wengenmayr ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Separation ◽  
Structural Changes ◽  
Bulk Material ◽  
Fluorine Content ◽  
Film Surface ◽  
Phase Behaviour ◽  
Side Chain ◽  
Side Chains ◽  
Polymer Backbone

Semifluorinated (SF) side chain polymers show phase separation between polymer backbone and SF side chains. Due to strong interaction between SF segments the side chains determine the structure behaviour strongly, often resulting in layered structures in which backbones and layers of SF side chains alternate. The interest in this work was directed to find out the dependence of these structures on concentration of SF side chains. Thin films of random copolymers consisting of methylmethacrylate (MMA) and semifluorinated side chain methacrylate (SFMA) segments and with different fluorine content in the perfluoroalkyl side chains (abbreviated as H10F10 and H2F8) were prepared by spin-coating. Phase separation and structure changes were initiated by external subsequent annealing. Corresponding bulk material served as basic information. Generation of ordered structures and variation of film parameters were observed using different X-ray scattering methods (XRR, GIWAXS, and GISAXS). The phase behaviour in bulk is governed by the SF side chain amount and their specific fluorine content which control the self-organization tendency of SF side chains. Additionally, the confinement in thin films generates an orientation of side chains normally to film surface.

scholarly journals Plasma Etching Behavior of SF6 Plasma Pre-Treatment Sputter-Deposited Yttrium Oxide Films

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 637
Author(s):  
Wei-Kai Wang ◽  
Sung-Yu Wang ◽  
Kuo-Feng Liu ◽  
Pi-Chuen Tsai ◽  
Yu-Hao Zhang ◽  
...  
Keyword(s):  
Yttrium Oxide ◽  
Plasma Etching ◽  
Photoelectron Spectroscopy ◽  
Film Surface ◽  
Chemical Compositions ◽  
Plasma Irradiation ◽  
Fluorocarbon Plasma ◽  
Sulfur Fluoride ◽  
Pre Treatment ◽  
Sputter Deposited

Yttrium oxyfluoride (YOF) protective materials were fabricated on sputter-deposited yttrium oxide (Y2O3) by high-density (sulfur fluoride) SF6 plasma irradiation. The structures, compositions, and fluorocarbon-plasma etching behaviors of these films were systematically characterized by various techniques. After exposure to SF6 plasma, the Y2O3 film surface was fluorinated significantly to form a YOF film with an approximate average thickness of 30 nm. X-ray photoelectron spectroscopy revealed few changes in the elemental and chemical compositions of the surface layer after fluorination, confirming the chemical stability of the YOF/Y2O3 sample. Transmission electron microscopy confirmed a complete lattice pattern on the YOF/Y2O3 structure after fluorocarbon plasma exposure. These results indicate that the SF6 plasma-treated Y2O3 film is more erosion resistant than the commercial Y2O3 coating, and thus accumulates fewer contamination particles.

Fabrication and Characterization of Lanthanum Treated Carboxyl-Graphene Oxide Self-Assembled Composite Film on Silicon Substrate

2016 ◽  
Vol 693 ◽  
pp. 566-575 ◽  
Author(s):  
Da Shu ◽  
Hong Gao ◽  
Da Bin Zhang
Keyword(s):  
Graphene Oxide ◽  
Silicon Substrate ◽  
Photoelectron Spectroscopy ◽  
Multilayer Film ◽  
Film Surface ◽  
Chloroacetic Acid ◽  
Chemical Compositions ◽  
Hydroxyl Groups ◽  
Water Contact ◽  
Micro Electro Mechanical Systems

The admixture of graphene oxide (GO) sheets and chloroacetic acid were ultrasonic treated. As a result, epoxy and hydroxyl groups which existed onto GO sheets were transformed into carboxyl groups. Then, the carboxyl-GO sheets were assembled on silicon substrate by taking use of 3-aminopropyltriethoxysilane (APS) as an intermediate coupling agent (marked as APS-GO). Furthermore, La elements were deposited on the APS-GO by means of chemisorption to form multilayer film (APS-GO-La). Chemical compositions, surface morphologies, and microstructures were investigated by using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and water contact angle (WCA). Experimental results suggested that carboxyl-GO sheets distributed homogeneously on Si substrate. Results also indicated that lanthanum elements can react with the-COOH functional groups of GO film and be adsorbed on the APS-GO film surface. The prepared APS-GO-La multilayer film showed low surface free energy, which has potential applications in nano/micro electro-mechanical systems (N/MEMS).

End-Blocked Silanization of Side-Chain Fluoroalkyl Oligoether and its Surface Properties

2018 ◽  
Vol 71 (11) ◽  
pp. 855
Author(s):  
Lei Wang ◽  
Lei Chen ◽  
Zhanxiong Li
Keyword(s):  
Contact Angle ◽  
Photoelectron Spectroscopy ◽  
Contact Angles ◽  
Side Chain ◽  
Chemical Compositions ◽  
Silicon Substrates ◽  
Water Contact ◽  
Molecular Weights ◽  
Self Assembled ◽  
Surface Morphologies

In this study, three novel side-chain fluoroalkyl oligoethers with different molecular weights were synthesised via a ring-opening reaction of 2,2,3,3,4,4,5,5,5-nonafluoropentyloxirane. The fluorooligoethers were then silanized and characterised by FT-IR,1H, and 19F NMR spectroscopies. These silanlized fluorooligoethers were used to fabricate hydrophobic coatings on silicon substrates, which were pre-treated with O2 plasma, by the method of liquid phase deposition. The chemical compositions and structures of the film surfaces were analysed by X-ray photoelectron spectroscopy and the results showed that silanized fluorooligoethers formed self-assembled films on the silicon wafer. The surface wettability of the coatings was measured by water contact angles. It is noted that the annealing process can improve the hydrophobicity with the highest water contact angle being 115.2 ± 1° and hexadecane contact angle being 67.2 ± 1°. The surface morphologies and roughness of the self-assembled films were measured by atomic force microscopy (AFM), as a result, the surface was found to be rougher with the increment of the molecular weight of the fluorooligoethers.

Order To Disorder Transition at The Polymer-Air Interface for Hydrophobic Octadecyl Side Chain Copolymers

2000 ◽  
Vol 661 ◽  
Author(s):  
Keshav S. Gautam ◽  
Ali Dhinojwala
Keyword(s):  
Transition Temperature ◽  
Molecular Orientation ◽  
Crystalline State ◽  
Liquid Crystalline ◽  
Side Chain ◽  
Side Chains ◽  
Disorder Transition ◽  
Sum Frequency ◽  
Air Interface ◽  
Alkyl Side Chains

ABSTRACTMolecular orientation of octadecyl alkyl side chains at the poly (vinyl octadecyl carbamates-co-vinyl acetate) polymer-air interface has been studied using surface sensitive sum frequency generation (SFG) spectroscopy. At 280C, below the side chain crystalline transition temperature, the SFG spectra show strong methyl vibrations indicating ordered alkyl side chains at the polymer-air interface. In the liquid state (980C), the SFG spectra show higher contributions from the methylene vibrations indicating higher gauche defects at the interface. This surface order to disorder transition is gradual and spans over a broad temperature range (50-900C), where the bulk is in the smectic liquid crystalline state.

The structure and stability of black foam films

1963 ◽  
Vol 273 (1352) ◽  
pp. 84-102 ◽  
Keyword(s):  
Film Surface ◽  
Film Plane ◽  
Bulk Solution ◽  
Bulk Liquid ◽  
Black Film ◽  
Foam Films ◽  
Air Interface ◽  
Surface Active ◽  
The Stability ◽  
Aqueous Core

The black film (50 to 100 A thick) has a simple lamellar structure in which two monolayers of surface-active molecules are spread on a thin aqueous core. The thickness of the film surface layers has been estimated from the simultaneous measurement of the total film thickness and the thickness of the aqueous core. From these measurements it has been concluded that the surface-active molecules are orientated perpendicularly to the film plane. Radiotracer experiments have shown th at the composition of the film surface is identical to the composition of the surface layer at the bulk solution/air interface. These surface concentrations are in excellent agreement with the limiting value calculated from the solution surface tensions by application of the Gibbs adsorption equation. The factors influencing the stability of the thin films have been discussed in terms of the evaporative equilibrium of the volatile film component. The equilibrium vapour pressure over a thin aqueous film should be greater than that over the bulk liquid phase. I t has been suggested that the stability of a black film can be maintained by an excess of solute, relative to the bulk solution, in the aqueous film core.

Influence of Flexible Side-Chains on the Breathing Phase Transition of Pillared Layer MOFs: A Force Field Investigation

2020 ◽  
Author(s):  
Julian Keupp ◽  
Johannes P. Dürholt ◽  
Rochus Schmid
Keyword(s):  
First Principles ◽  
Good Accuracy ◽  
Field Investigation ◽  
Square Lattice ◽  
Side Chain ◽  
Second Step ◽  
Side Chains ◽  
Dynamics Simulations ◽  
Complex Phenomena ◽  
Closed Pore

The prototypical pillared layer MOFs, formed by a square lattice of paddle-<br>wheel units and connected by dinitrogen pillars, can undergo a breathing phase<br>transition by a “wine-rack” type motion of the square lattice. We studied this not<br>yet fully understood behavior using an accurate first principles parameterized force<br>field (MOF-FF) for larger nanocrystallites on the example of Zn 2 (bdc) 2 (dabco) [bdc:<br>benzenedicarboxylate, dabco: (1,4-diazabicyclo[2.2.2]octane)] and found clear indi-<br>cations for an interface between a closed and an open pore phase traveling through<br>the system during the phase transformation [Adv. Theory Simul. 2019, 2, 11]. In<br>conventional simulations in small supercells this mechanism is prevented by periodic<br>boundary conditions (PBC), enforcing a synchronous transformation of the entire<br>crystal. Here, we extend this investigation to pillared layer MOFs with flexible<br>side-chains, attached to the linker. Such functionalized (fu-)MOFs are experimen-<br>tally known to have different properties with the side-chains acting as fixed guest<br>molecules. First, in order to extend the parameterization for such flexible groups,<br>1a new parametrization strategy for MOF-FF had to be developed, using a multi-<br>structure force based fit method. The resulting parametrization for a library of<br>fu-MOFs is then validated with respect to a set of reference systems and shows very<br>good accuracy. In the second step, a series of fu-MOFs with increasing side-chain<br>length is studied with respect to the influence of the side-chains on the breathing<br>behavior. For small supercells in PBC a systematic trend of the closed pore volume<br>with the chain length is observed. However, for a nanocrystallite model a distinct<br>interface between a closed and an open pore phase is visible only for the short chain<br>length, whereas for longer chains the interface broadens and a nearly concerted trans-<br>formation is observed. Only by molecular dynamics simulations using accurate force<br>fields such complex phenomena can be studied on a molecular level.

scholarly journals Effects of Amino Acid Side-Chain Length and Chemical Structure on Anionic Polyglutamic and Polyaspartic Acid Cellulose-Based Polyelectrolyte Brushes

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1789
Author(s):  
Dmitry Tolmachev ◽  
George Mamistvalov ◽  
Natalia Lukasheva ◽  
Sergey Larin ◽  
Mikko Karttunen
Keyword(s):  
Glutamic Acid ◽  
Chain Length ◽  
Chemical Structure ◽  
Side Chain ◽  
Side Chains ◽  
Side Chain Length ◽  
Polyelectrolyte Brushes ◽  
Grafting Density ◽  
The Difference ◽  
Cellulose Surface

We used atomistic molecular dynamics (MD) simulations to study polyelectrolyte brushes based on anionic α,L-glutamic acid and α,L-aspartic acid grafted on cellulose in the presence of divalent CaCl2 salt at different concentrations. The motivation is to search for ways to control properties such as sorption capacity and the structural response of the brush to multivalent salts. For this detailed understanding of the role of side-chain length, the chemical structure and their interplay are required. It was found that in the case of glutamic acid oligomers, the longer side chains facilitate attractive interactions with the cellulose surface, which forces the grafted chains to lie down on the surface. The additional methylene group in the side chain enables side-chain rotation, enhancing this effect. On the other hand, the shorter and more restricted side chains of aspartic acid oligomers prevent attractive interactions to a large degree and push the grafted chains away from the surface. The difference in side-chain length also leads to differences in other properties of the brush in divalent salt solutions. At a low grafting density, the longer side chains of glutamic acid allow the adsorbed cations to be spatially distributed inside the brush resulting in a charge inversion. With an increase in grafting density, the difference in the total charge of the aspartic and glutamine brushes disappears, but new structural features appear. The longer sides allow for ion bridging between the grafted chains and the cellulose surface without a significant change in main-chain conformation. This leads to the brush structure being less sensitive to changes in salt concentration.

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