impermeable barrier films and protective coatings based on reduced graphene oxide - high barrier packaging films
For many industries, from food to medical care, from chemical to electronics, flexible barrier films that prevent gas and moisture penetration are very important.
From this point of view, graphene has recently attracted special interest because of its defects.
For all atoms and molecules, free single layer does not penetrate.
However, the development of large enterprises has proved to be a challenge.
Defect-free graphene film suitable for industrial use.
Here, we report the barrier properties of a multi-layer graphite film made of hydrogen iodine acid and vitamin C mild chemical reduction graphene oxide laminate.
It is found that they have a high degree of non-permeability to all gases, liquids and corrosive chemicals, including, for example, hf.
The special barrier properties are attributed to the high degree of graphite of the laminate and the reduction of small structural damage during the process.
This work heralds the development of graphene.
Based on flexible and inert barriers and protective coatings, this may be of interest to many applications.
Graphite oxide was prepared by Hummers method, and then dispersed in water by ultrasonic wave to obtain a stable GO solution.
The size of a single GO sheet is from ~ 0 change.
2-20 μm, we did not find any significant size dependence in the above barrier performance.
We used two types of RGO samples: free-
Supporting film and supporting film on various substrates. The free-
As stated in the reference, an upright membrane was prepared by vacuum filtration with a thickness from 0. 5 to 5u2009μm.
Supported film by rod-
Coating or spraying-
12-coating on topμm-
Thick PET film, metal foil and oxidized silicon wafer.
In the hydrogen-ar mixture, a thermal reduction of 4 u2009 h was performed at 300 °c.
HI reduction is carried out by exposing the GO film to acid steam at 90 °c.
The exposure time varies from 5 minutes to 30 minutes, depending.
The samples were then rinsed repeatedly with ethanol to remove the residual HI.
For VC reduction, dip the GO film into the aqueous solution of VC (30u2009gu2009l)
For 1 hour at 90 °c.
To characterize the RGO film on PET, we used a scanning electron microscope, an atomic force microscope (AFM)
Display absorption spectrum of 30-nm-
Thick film of HI-RGO.
For visible spectra, the transmission ratio varies between 30 and 40%.
In ambient conditions, the thickness of the RGO coating is measured using an AFM with a Veeco size of 3100 in tapping mode.
The illustration shows a representative AFM image of 30-nm-thick HI-RGO on PET.
The penetration properties of various RGO films were measured using several techniques described in detail before.
In short, for steam penetration measurement, freedom-
Standing film and RGO-on-
The PET film is glued to the copper foil and the opening is 2-cm diameter.
Foil sandwiched between two dinnitrile rubber O-
Sealing ring of metal container.
The penetration rate is measured by monitoring the weight loss of containers filled with water and other liquids in the glovebox.
In the gas penetration experiment, GO-on-
The PET film is placed between two standard rubber washers and pressurized from one side to 1 bar.
Monitoring gas penetration across the street (vacuum)
Analysis by mass spectrometry.
We used the INFICON UL200 that can detect helium and hydrogen.
Calculated permeability from our weight loss measurement is = ×/×Δ, where the weight loss rate, the thickness of the film, its area and the differential pressure of water vapor on the film.
Conduct a moisture penetration experiment in a glove box with negligible water vapor (