Limits...
Evaluation of the surface free energy of plant surfaces: toward standardizing the procedure.

Fernández V, Khayet M - Front Plant Sci (2015)

Bottom Line: Plant surfaces have been found to have a major chemical and physical heterogeneity and play a key protecting role against multiple stress factors.During the last decade, there is a raising interest in examining plant surface properties for the development of biomimetic materials.Regardless of the degree of surface roughness, the methods based on 2 test liquids often led to the under- or over-estimation of surface free energies as compared to the results derived from the 3-Liquids method.

View Article: PubMed Central - PubMed

Affiliation: Forest Genetics and Ecophysiology Research Group, Plant Physiology and Anatomy Unit, School of Forest Engineering, Technical University of Madrid Madrid, Spain.

ABSTRACT
Plant surfaces have been found to have a major chemical and physical heterogeneity and play a key protecting role against multiple stress factors. During the last decade, there is a raising interest in examining plant surface properties for the development of biomimetic materials. Contact angle measurement of different liquids is a common tool for characterizing synthetic materials, which is just beginning to be applied to plant surfaces. However, some studies performed with polymers and other materials showed that for the same surface, different surface free energy values may be obtained depending on the number and nature of the test liquids analyzed, materials' properties, and surface free energy calculation methods employed. For 3 rough and 3 rather smooth plant materials, we calculated their surface free energy using 2 or 3 test liquids and 3 different calculation methods. Regardless of the degree of surface roughness, the methods based on 2 test liquids often led to the under- or over-estimation of surface free energies as compared to the results derived from the 3-Liquids method. Given the major chemical and structural diversity of plant surfaces, it is concluded that 3 different liquids must be considered for characterizing materials of unknown physico-chemical properties, which may significantly differ in terms of polar and dispersive interactions. Since there are just few surface free energy data of plant surfaces with the aim of standardizing the calculation procedure and interpretation of the results among for instance, different species, organs, or phenological states, we suggest the use of 3 liquids and the mean surface tension values provided in this study.

No MeSH data available.


Related in: MedlinePlus

Contact angles of water (A,D), glycerol (B,E) and diiomethane (C,F) on to blue gum (rough surface; A–C) and pepper fruit (smooth surface; D–F) surfaces, as an example.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4493370&req=5

Figure 2: Contact angles of water (A,D), glycerol (B,E) and diiomethane (C,F) on to blue gum (rough surface; A–C) and pepper fruit (smooth surface; D–F) surfaces, as an example.

Mentions: The contact angle values of W, G, and DM with the surface of the examined plant materials are shown in Table 2. In Figure 2 the contact angles of water (W), glycerol (G), and diiodomethane (DM) with one of the rough (blue gum leaf) and smooth (pepper fruit) surfaces analyzed are shown as an example. The structural complexity observed in the adaxial surfaces of red ironbark, blue gum eucalypt, and abaxial holm-oak leaf surfaces led to very high contact angles with polar liquids (i.e., W and G; Figures 2A,B). While the blue gum eucalypt leaf is wettable (θ < 90°) for DM (Figure 2C), which suggests the occurrence of chemical interactions between such liquid and epicuticular wax nano-tubes, the surfaces of red ironbark and holm oak leaves are unwettable (θ > 90°) for such largely apolar liquid.


Evaluation of the surface free energy of plant surfaces: toward standardizing the procedure.

Fernández V, Khayet M - Front Plant Sci (2015)

Contact angles of water (A,D), glycerol (B,E) and diiomethane (C,F) on to blue gum (rough surface; A–C) and pepper fruit (smooth surface; D–F) surfaces, as an example.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493370&req=5

Figure 2: Contact angles of water (A,D), glycerol (B,E) and diiomethane (C,F) on to blue gum (rough surface; A–C) and pepper fruit (smooth surface; D–F) surfaces, as an example.
Mentions: The contact angle values of W, G, and DM with the surface of the examined plant materials are shown in Table 2. In Figure 2 the contact angles of water (W), glycerol (G), and diiodomethane (DM) with one of the rough (blue gum leaf) and smooth (pepper fruit) surfaces analyzed are shown as an example. The structural complexity observed in the adaxial surfaces of red ironbark, blue gum eucalypt, and abaxial holm-oak leaf surfaces led to very high contact angles with polar liquids (i.e., W and G; Figures 2A,B). While the blue gum eucalypt leaf is wettable (θ < 90°) for DM (Figure 2C), which suggests the occurrence of chemical interactions between such liquid and epicuticular wax nano-tubes, the surfaces of red ironbark and holm oak leaves are unwettable (θ > 90°) for such largely apolar liquid.

Bottom Line: Plant surfaces have been found to have a major chemical and physical heterogeneity and play a key protecting role against multiple stress factors.During the last decade, there is a raising interest in examining plant surface properties for the development of biomimetic materials.Regardless of the degree of surface roughness, the methods based on 2 test liquids often led to the under- or over-estimation of surface free energies as compared to the results derived from the 3-Liquids method.

View Article: PubMed Central - PubMed

Affiliation: Forest Genetics and Ecophysiology Research Group, Plant Physiology and Anatomy Unit, School of Forest Engineering, Technical University of Madrid Madrid, Spain.

ABSTRACT
Plant surfaces have been found to have a major chemical and physical heterogeneity and play a key protecting role against multiple stress factors. During the last decade, there is a raising interest in examining plant surface properties for the development of biomimetic materials. Contact angle measurement of different liquids is a common tool for characterizing synthetic materials, which is just beginning to be applied to plant surfaces. However, some studies performed with polymers and other materials showed that for the same surface, different surface free energy values may be obtained depending on the number and nature of the test liquids analyzed, materials' properties, and surface free energy calculation methods employed. For 3 rough and 3 rather smooth plant materials, we calculated their surface free energy using 2 or 3 test liquids and 3 different calculation methods. Regardless of the degree of surface roughness, the methods based on 2 test liquids often led to the under- or over-estimation of surface free energies as compared to the results derived from the 3-Liquids method. Given the major chemical and structural diversity of plant surfaces, it is concluded that 3 different liquids must be considered for characterizing materials of unknown physico-chemical properties, which may significantly differ in terms of polar and dispersive interactions. Since there are just few surface free energy data of plant surfaces with the aim of standardizing the calculation procedure and interpretation of the results among for instance, different species, organs, or phenological states, we suggest the use of 3 liquids and the mean surface tension values provided in this study.

No MeSH data available.


Related in: MedlinePlus