Layer-by-layer assembly of graphene on polyimide films via thermal imidization and synchronous reduction of graphene oxide

• Published in: Macromolecular research 2017, 25(6), , pp.496-499
• Main Authors: Li, Yuheng, Choi, Myeon-Cheon, Jeong, Keuk-Min, Jeong, Jae Hoon, Lee, Hyeok-Gi, Kim, Gue-Hyun, Ha, Chang-Sik
• Format: Article
• Language: English
• Subjects: Assembly; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Communication; Complex Fluids and Microfluidics; Deposition; Electrical resistivity; Flat surfaces; Gas transmission; Graphene; Milk; Molecular weight; Morphology; Nanochemistry; Nanotechnology; Permeability; Physical Chemistry; Polyethyleneimine; Polymer Sciences; Soft and Granular Matter; Transmission rate (communications); Weight reduction; 고분자공학
• ISSN: 1598-5032; 2092-7673
• DOI: 10.1007/s13233-017-5093-x

To investigate the effects of holding time after deposition of polyethylenimine (PEI) solution and molecular weight of PEI on the surface morphology of multi-layer films prepared by layer-by-layer (LbL) method, polyamic acid (PAA)/PEI/graphene oxide (GO) films were prepared using different holding times and different molecular weights of PEI. To convert PAA into polyimide (PI), the films were thermally imidized after film deposition. In this process, GO was also converted into partially reduced GO (rGO). The effects of holding time and molecular weight of PEI on the surface morphology and the sheet resistance of PI/PEI/rGO films were investigated. Also, to investigate the effect of rGO on the barrier properties of PI based multilayer films, (PI/PEI/rGO/PEI) 6 films were prepared by LbL method. Longer holding time (10 min) and smaller molecular weight (25,000) of PEI lead to relatively flat surfaces, but shorter holding time (5 min) and larger molecular weight (75,000) result in wrinkled and overlapped surfaces. The sheet resistance of PI/PEI 25K /rGO films prepared with holding time 10 and 5 min is 502.1 kΩ/sq and out of range (> 2000 kΩ/sq), respectively. The sheet resistance of PI/PEI 75K /rGO films prepared with holding time 10 min is out of range (> 2000 kΩ/sq). Gas transmission rate (GTR) and permeability coefficient of (PI/PEI 25K /rGO/PEI 25K ) 6 are lower than those of (PI/PEI 75K /rGO/PEI 75K ) 6 , respectively.