Influence of structural feature of aluminum coatings on mechanical and water barrier properties of metallized PET films

Abstract

This article focuses on description and evaluation of multilayer films, which are used for vacuum insulation panels (VIP). The materials investigated include a neat polyethylene terephthalate (PET) and PET films coated by chemical vapor deposition with different aluminum thicknesses. The aim of these investigations was to evaluate the influence of structural features on the physical properties of Al/PET systems. The morphological analyzes associated to water vapor permeability measurements showed that the metallized surface exhibited defects through which a small amount of water vapor can permeate. It is shown that the permeance varies linearly with the surface fraction occupied by pinholes which in turn changes linearly with the aluminum thickness.

Impermeable barrier films and protective coatings based on reduced graphene oxide

“…1b). Despite being only the limit for our detection technique, this value is already nearly two orders of magnitude lower than water transparency for the industry-standard barrier films (aluminized PET) 30 . Note that the HI-RGO membranes were impermeable under both liquid and vapour conditions, with the former studied by using the same container but turned upside down so that liquid water was in direct contact with the membranes (See methods).…”

“…This yields an upper limit for water permeation through HI-RGO films of submicron thickness as 10 -11 mmg/cm 2 sbar (see Fig. 1b), which is two orders of magnitude lower than water transparency for the industry-standard barrier films (aluminized PET) 28,29 . We also performed permeation measurements for several organic solvents such as acetone, methanol, ethanol and propanol.…”

“…No permeation could be detected for either original GO (as reported previously 5 ) or reduced membranes. 28,29 .…”

“…30 . The green symbols are for a 40 nm thick aluminum film on PET (solid squares, our measurements; open symbol, the literature value 28,29 ). The violet and read arrows indicate our detection limits for 30 and 200 nm HI-RGO, respectively.…”

Impermeable barrier films and protective coatings based on reduced graphene oxide

“…1b). Despite being only the limit for our detection technique, this value is already nearly two orders of magnitude lower than water transparency for the industry-standard barrier films (aluminized PET) 30 . Note that the HI-RGO membranes were impermeable under both liquid and vapour conditions, with the former studied by using the same container but turned upside down so that liquid water was in direct contact with the membranes (See methods).…”

“…This yields an upper limit for water permeation through HI-RGO films of submicron thickness as 10 -11 mmg/cm 2 sbar (see Fig. 1b), which is two orders of magnitude lower than water transparency for the industry-standard barrier films (aluminized PET) 28,29 . We also performed permeation measurements for several organic solvents such as acetone, methanol, ethanol and propanol.…”

“…No permeation could be detected for either original GO (as reported previously 5 ) or reduced membranes. 28,29 .…”

“…30 . The green symbols are for a 40 nm thick aluminum film on PET (solid squares, our measurements; open symbol, the literature value 28,29 ). The violet and read arrows indicate our detection limits for 30 and 200 nm HI-RGO, respectively.…”

Degradation Mechanisms in Metallized Barrier Films for Vacuum Insulation Panels Subjected to Flanging-Induced Stress

“…Modern designs utilize plasma-enhanced chemical vapor deposition (PECVD) to apply ultrathin aluminum coatings (30–100 nm) onto flexible 12–25 μm PET substrates ( Figure 2 b). However, intrinsic microdefects in metallized layers permit gas permeation proportional to both pinhole density and aluminum thickness [ 27 ]. This limitation is addressed through EVOH integration, which compensates for potential defects or inhomogeneities in the aluminum coating via its molecular-level crystalline barrier structure.…”

Impermeable barrier films and protective coatings based on reduced graphene oxide

“…1b). Despite being only the limit for our detection technique, this value is already nearly two orders of magnitude lower than water transparency for the industry-standard barrier films (aluminized PET) 30 . Note that the HI-RGO membranes were impermeable under both liquid and vapour conditions, with the former studied by using the same container but turned upside down so that liquid water was in direct contact with the membranes (See methods).…”

“…This yields an upper limit for water permeation through HI-RGO films of submicron thickness as 10 -11 mmg/cm 2 sbar (see Fig. 1b), which is two orders of magnitude lower than water transparency for the industry-standard barrier films (aluminized PET) 28,29 . We also performed permeation measurements for several organic solvents such as acetone, methanol, ethanol and propanol.…”

“…No permeation could be detected for either original GO (as reported previously 5 ) or reduced membranes. 28,29 .…”

“…30 . The green symbols are for a 40 nm thick aluminum film on PET (solid squares, our measurements; open symbol, the literature value 28,29 ). The violet and read arrows indicate our detection limits for 30 and 200 nm HI-RGO, respectively.…”

Degradation Mechanisms in Metallized Barrier Films for Vacuum Insulation Panels Subjected to Flanging-Induced Stress

“…Modern designs utilize plasma-enhanced chemical vapor deposition (PECVD) to apply ultrathin aluminum coatings (30–100 nm) onto flexible 12–25 μm PET substrates ( Figure 2 b). However, intrinsic microdefects in metallized layers permit gas permeation proportional to both pinhole density and aluminum thickness [ 27 ]. This limitation is addressed through EVOH integration, which compensates for potential defects or inhomogeneities in the aluminum coating via its molecular-level crystalline barrier structure.…”

Impermeable barrier films and protective coatings based on reduced graphene oxide

“…1b). Despite being only the limit for our detection technique, this value is already nearly two orders of magnitude lower than water transparency for the industry-standard barrier films (aluminized PET) 30 . Note that the HI-RGO membranes were impermeable under both liquid and vapour conditions, with the former studied by using the same container but turned upside down so that liquid water was in direct contact with the membranes (See methods).…”

“…This yields an upper limit for water permeation through HI-RGO films of submicron thickness as 10 -11 mmg/cm 2 sbar (see Fig. 1b), which is two orders of magnitude lower than water transparency for the industry-standard barrier films (aluminized PET) 28,29 . We also performed permeation measurements for several organic solvents such as acetone, methanol, ethanol and propanol.…”

“…No permeation could be detected for either original GO (as reported previously 5 ) or reduced membranes. 28,29 .…”

“…30 . The green symbols are for a 40 nm thick aluminum film on PET (solid squares, our measurements; open symbol, the literature value 28,29 ). The violet and read arrows indicate our detection limits for 30 and 200 nm HI-RGO, respectively.…”

Degradation Mechanisms in Metallized Barrier Films for Vacuum Insulation Panels Subjected to Flanging-Induced Stress

“…Modern designs utilize plasma-enhanced chemical vapor deposition (PECVD) to apply ultrathin aluminum coatings (30–100 nm) onto flexible 12–25 μm PET substrates ( Figure 2 b). However, intrinsic microdefects in metallized layers permit gas permeation proportional to both pinhole density and aluminum thickness [ 27 ]. This limitation is addressed through EVOH integration, which compensates for potential defects or inhomogeneities in the aluminum coating via its molecular-level crystalline barrier structure.…”