Quantification of dominant diffusion processes through plasma enhanced chemical vapor deposition-coated plastics by combining two complementary methods for porosity analysis
Abstract:Thin plasma polymerized gas barrier coatings were applied on PET films using low-pressure microwave excited hexamethyldisiloxane plasma. Oxygen and water vapor transmission rates were determined for the same barrier coating of varying thickness and correlated with the coating porosity. The porosity was quantified on different scales with two complementary methods. A plasma etching process with subsequent high-resolution SEM imaging and an automated defect detection as well as an overall porosity measurement by… Show more
“…Often, the changes in the pore size also includes the surface pores and thus the surface roughness. Figure 7 shows the changes in the surface morphology of membranes upon variation in the CVD deposition time upon which not only the changes in pore size but also in thickness were noticeable 192 . Figure 6 (c) exhibits the effect of deposition time on contact angle.…”
Section: Cvd Process Parameters Selection and Controlmentioning
confidence: 99%
“…Further reduction in He permeability up to ~25% was possible but required stacking five layers of graphene deposition. In another attempt, Wilski et al 192 employed low pressure PECVD to coat silica on a PET film. Their best membrane showed 96% and 92% decrease in oxygen and water vapor transmission rates, respectively, compared to the neat PET.…”
Section: Progress In Applications Of Cvd‐based Thin Films and Membranesmentioning
confidence: 99%
“…As can be seen in Table 1, there are several studies on the use of PET substrates for CVD, particularly to enhance oxygen and water vapor barrier properties. Specifically, silica and silicon‐based coatings have been applied by CVD which effectively improved the impermeability by more than 90% 142,167,192,215 …”
Section: Materials Selection For Cvd Processesmentioning
confidence: 99%
“…The influence of CVD deposition time on three key characteristics of the coating: (a) coating thickness, (b) pore size, and (c) surface contact angle. 84,171,187,192,200,201,255 [Color figure can be viewed at wileyonlinelibrary.com] dichalcogenides (TMDs) which are a class of materials with growing interests due to their unusual electrical, optical, and mechanical properties. The three-atom thick unit cell of TMDs is created by a layer of transition metal atoms sandwiched between two layers of chalcogen atoms.…”
Section: Deposition Temperaturementioning
confidence: 99%
“…The influence of CVD deposition time on three key characteristics of the coating: (a) coating thickness, (b) pore size, and (c) surface contact angle 84,171,187,192,200,201,255 . [Color figure can be viewed at wileyonlinelibrary.com]…”
Section: Cvd Process Parameters Selection and Controlmentioning
Advanced materials are among the prime drivers for technological revolutions and transformation in quality of lives. Over time, several modification techniques have emerged enabling development of novel materials with extraordinary features. The present review aims to introduce various promising chemical and physical surface modification techniques instrumental for tailoring the characteristics of thin films and membranes. Meticulous discussions are provided over chemical vapor deposition (CVD) techniques evolved for addressing the demands for materials with desired functionalities. Also, essential criteria for the selection of substrates, modifying and precursor materials for an effective CVD modification are elaborated. Investigations are extended to unraveling the role of various process parameters on the quality and properties of deposition. Special attention is paid to the significance and performance of CVD‐based membranes and thin films for industrial applications ranging from desalination and water treatment to energy and environment, biomedical and life science as well as packaging. The goal has been to establish a scientific platform for a timely tracking of the prevailing trends in exploitation of CVD techniques and highlighting the unexplored opportunities. This also helps in identification of the scientific and technical gaps and setting directions for further progress in the fields of thin films and membranes.
“…Often, the changes in the pore size also includes the surface pores and thus the surface roughness. Figure 7 shows the changes in the surface morphology of membranes upon variation in the CVD deposition time upon which not only the changes in pore size but also in thickness were noticeable 192 . Figure 6 (c) exhibits the effect of deposition time on contact angle.…”
Section: Cvd Process Parameters Selection and Controlmentioning
confidence: 99%
“…Further reduction in He permeability up to ~25% was possible but required stacking five layers of graphene deposition. In another attempt, Wilski et al 192 employed low pressure PECVD to coat silica on a PET film. Their best membrane showed 96% and 92% decrease in oxygen and water vapor transmission rates, respectively, compared to the neat PET.…”
Section: Progress In Applications Of Cvd‐based Thin Films and Membranesmentioning
confidence: 99%
“…As can be seen in Table 1, there are several studies on the use of PET substrates for CVD, particularly to enhance oxygen and water vapor barrier properties. Specifically, silica and silicon‐based coatings have been applied by CVD which effectively improved the impermeability by more than 90% 142,167,192,215 …”
Section: Materials Selection For Cvd Processesmentioning
confidence: 99%
“…The influence of CVD deposition time on three key characteristics of the coating: (a) coating thickness, (b) pore size, and (c) surface contact angle. 84,171,187,192,200,201,255 [Color figure can be viewed at wileyonlinelibrary.com] dichalcogenides (TMDs) which are a class of materials with growing interests due to their unusual electrical, optical, and mechanical properties. The three-atom thick unit cell of TMDs is created by a layer of transition metal atoms sandwiched between two layers of chalcogen atoms.…”
Section: Deposition Temperaturementioning
confidence: 99%
“…The influence of CVD deposition time on three key characteristics of the coating: (a) coating thickness, (b) pore size, and (c) surface contact angle 84,171,187,192,200,201,255 . [Color figure can be viewed at wileyonlinelibrary.com]…”
Section: Cvd Process Parameters Selection and Controlmentioning
Advanced materials are among the prime drivers for technological revolutions and transformation in quality of lives. Over time, several modification techniques have emerged enabling development of novel materials with extraordinary features. The present review aims to introduce various promising chemical and physical surface modification techniques instrumental for tailoring the characteristics of thin films and membranes. Meticulous discussions are provided over chemical vapor deposition (CVD) techniques evolved for addressing the demands for materials with desired functionalities. Also, essential criteria for the selection of substrates, modifying and precursor materials for an effective CVD modification are elaborated. Investigations are extended to unraveling the role of various process parameters on the quality and properties of deposition. Special attention is paid to the significance and performance of CVD‐based membranes and thin films for industrial applications ranging from desalination and water treatment to energy and environment, biomedical and life science as well as packaging. The goal has been to establish a scientific platform for a timely tracking of the prevailing trends in exploitation of CVD techniques and highlighting the unexplored opportunities. This also helps in identification of the scientific and technical gaps and setting directions for further progress in the fields of thin films and membranes.
Vapor phase infiltration (VPI) has emerged as a promising tool for fabrication of novel hybrid materials. In the field of polymeric gas separation membranes, a beneficial impact on stability and membrane performance is known for several polymers with differing functional groups. This study for the first time investigates VPI of trimethylaluminum (TMA) into poly(1‐trimethylsilyl‐1‐propyne) (PTMSP), featuring a carbon–carbon double bond as functional group. Saturation of the precursor inside the polymer is already attained after 60 s infiltration time leading to significant densification of the material. Depth profiling proves accumulation of aluminum in the polymer itself, but a significantly increased accumulation is visible in the gradient layer between polymer and SiO2 substrate. A reaction pathway is proposed and supplemented by density‐functional theory (DFT) calculations. Infrared spectra derived from both experiments and simulation support the presented reaction pathway. In terms of permeance, a favorable impact on selectivity is observed for infiltration times up to 1 s. Longer infiltration times yield greatly reduced permeance values close or even below the detection limit of the measurement device. The present results of this study set a strong basis for the application of VPI on polymers for gas‐barrier and membrane applications in the future.
This feature article presents insights concerning the correlation of plasma‐enhanced chemical vapor deposition and plasma‐enhanced atomic layer deposition thin film structures with their barrier or membrane properties. While in principle similar precursor gases and processes can be applied, the adjustment of deposition parameters for different polymer substrates can lead to either an effective diffusion barrier or selective permeabilities. In both cases, the understanding of the film growth and the analysis of the pore size distribution and the pore surface chemistry is of utmost importance for the understanding of the related transport properties of small molecules. In this regard, the article presents both concepts of thin film engineering and analytical as well as theoretical approaches leading to a comprehensive description of the state of the art in this field. Perspectives of future relevant research in this area, exploiting the presented correlation of film structure and molecular transport properties, are presented.
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