Mechanical properties of ladder-like polysilsesquioxane-based hard coating films containing different organic functional groups

Seon Oh Hwang, Albert S. Lee, Ju Yeon Lee, Sang Hee Park, Kevin Injoe Jung, Hyun Wook Jung, Jung Hyun Lee

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)


A series of ladder-like polysilsesquioxanes (LPSQs) containing the UV-curable methacryoxypropyl (MA) and different organic functional (R) groups (propyl, hexyl, cyclohexyl, phenyl or naphthyl) at the fixed MA/R molar ratio were synthesized as hard coating materials. The LPSQ hard coating films prepared by a simple UV curing process exhibited excellent optical transparency in the visible light range. X-ray diffraction analysis of the LPSQ films characterized how their intermolecular chain-to-chain distance and thus chain packing density varied according to the organic functional group. In addition, the hardness, elastic modulus and scratch resistance of the LPSQ films were evaluated by nanoindentation and nanoscratch tests. Although the mechanical properties of the LPSQ films were affected by both the chain rigidity of the organic functional group and the chain packing density of the siloxane backbones, chain rigidity played the dominant role in determining their mechanical robustness. Hence, despite its lowest chain packing density, the LPSQ film with the naphthyl group exhibited the best mechanical properties due to its high chain rigidity derived from the increased aromaticity of the naphthyl group. This study suggests the key factor when designing mechanically durable, scratch resistant hard coating films is the chain rigidity of the film network.

Original languageEnglish
Pages (from-to)105-111
Number of pages7
JournalProgress in Organic Coatings
Publication statusPublished - 2018 Aug

Bibliographical note

Funding Information:
This research was supported by KCC Corporation research fund and a Korea University Future Research Grant .

Publisher Copyright:
© 2018 Elsevier B.V.


  • Hard coating films
  • Hybrid materials
  • Ladder-like polysilsesquioxanes
  • Mechanical properties
  • Scratch resistance
  • Silicone

ASJC Scopus subject areas

  • General Chemical Engineering
  • Surfaces, Coatings and Films
  • Organic Chemistry
  • Materials Chemistry


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