Lignin: Functional Biomaterial with Potential in Surface Chemistry and Nanoscience - The Nanoscience and Technology of Renewable Biomaterials - page 189

Table7.4 Previouslypublishedmethodsforthepreparationof ligninmodelsurfaceson
varioussubstrates.

Film preparation Lignin source(s) Substrate References

method
Evaporation, heat
molding

Softwood (Indulin AT,
dioxane lignin,
periodate lignin),
hardwood (REAX 31)

Glass Lee and Luner 1972

Evaporation,
spin-coating

ZL-DHP (synthesized) Glass Micic etal. 2000,

2001a, 2001b
and 2004

Langmuir-Blodgett Sugar cane bagasse

(acetosolv lignin), Pinus
caribaea hondurensis
(organosolv lignin)

Glass, calcium
fluoride

Constantino etal.
1996, 1998 and
2000

Langmuir-Blodgett,
evaporation

Sugar cane bagasse
(saccharification lignin,
ethanol lignin, acetone-
oxygene lignin, soda
lignin)

Mica Pasquini 2002 and

2005

Adsorption Lignosulfonate

(commercial)

Glass, quartz Paterno and

Mattoso 2001

Adsorption Softwood (CURAN 100) Mica Maximova etal.

2004

Spin coating Softwood kraft lignin Oxidized

silicon wafer

Norgren etal. (2006
and 2007), Notley
etal. (2006),
Notley and
Norgren (2008)

Spin coating Milled wood lignin Polystyrene Tammelin etal.

(2006 and 2007)

demonstrated by the atomic force microscopy imaging shown in Figure 7.10. Typically,
the surface roughness of the lignin surfaces is less than 1 nm over a 1

m 2 image.
Macroscopically, the lignin films supported on the silica substrate are continuous over
greater than 1 mm. Furthermore, the ToF-SIMS analysis showed only a minimal amount
of solvent retained in the lignin layer and that the chemical integrity of the monolignols
was maintained.
Importantly, lignin surfaces made using the methodology of Norgren et al . remain
intact upon exposure of the film to a range of aqueous solution conditions. This has
allowed advancement in the study of the physicochemical properties of lignin in pulp and
paper applications that has not been previously possible. To test the stability of the thin
films, kraft lignin surfaces prepared on silica wafer were subjected to various aqueous
electrolyte solutions. Low concentrations of NaCl had little effect on the thickness of
the films whilst only a minimal decrease in thickness was observed for concentrations up
to 0.1 M. Furthermore, no changes were observed for solution pH in the region of 6-9.

µ