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Effects of material property and heat treatment on nanomechanical properties of chitosan films
Author(s) -
Majd Shervin,
Yuan Youling,
Mishra Sanjay,
Haggard Warren O.,
Bumgardner Joel D.
Publication year - 2009
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.31284
Subject(s) - nanoindentation , materials science , chitosan , crystallinity , composite material , coating , elastic modulus , casting , atomic force microscopy , modulus , young's modulus , chemical engineering , nanotechnology , engineering
The influence of degree of deacetylation (DDA), molecular weight (MW), and heat treatment on nanomechanical properties of three different chitosan coatings was assessed. Chitosans (2.5 wt % in 2% acetic acid) were solution cast and bonded to glass slides, subjected to 40, 70, or 90°C heat treatments for 1 h, and then allowed to air dry. Non‐heat treated films were used as controls. The nanomechanical and structural properties were evaluated using quasi‐static nanoindentation, X‐ray diffraction (XRD), and atomic force microscopy (AFM). Nanoindentation results showed that the coating with the lowest MW and highest DDA (95.6% DDA and MW = 2.43 × 10 6 Da) had higher reduced modulus of elasticity, ( E = 4.02 ± 0.85 GPa) as compared to the other chitosans; 76.1% DDA/MW = 3.20 × 10 6 Da, E = 3.66 ± 0.68 GPa, and 92.3% DDA/MW = 7.52 × 10 6 Da, E = 3.56 ± 0.25 GPa; ( n = 75, p < 0.05). Crystallinity index, estimated via XRD, ranged from 36.4% ± 1% to 49.7% ± 6.5%. AFM revealed the presence of different crystalline morphologies such as needle‐like crystals, sheet‐like crystals, and small spherulites. The heat treatments applied during solution casting of the chitosan coatings did not affect morphology or nanomechanical properties. In conclusion, nanomechanical properties of chitosan coatings varied with DDA and MW and may be important to cell/tissue interactions. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009