Organization behavior of guaiacyl and guaiacyl/syringyl dehydrogenation polymers (lignin model compounds) at the air/water interface

In plant cell walls, lignins are closely associated with hydrophilic polysa ccharides. In these associations, the interface between the two polymers ma y have a strong influence on the molecular architecture of plant cell walls . To model such hydrophilic/hydrophobic and anisotropic media, two DHPs (de hydrogenation polymer models of lignins, one guaiacyl type (G) and one mixe d guaiacyl/syringyl type (GS)) were spread at the air/water interface. The investigation of these two DHP layers at the air/water interface by neutron reflectivity has demonstrated that both DHPs form a nonhomogeneous structu re with DHP distribution going from a concentrate structure at the air side to a dilute one at the water side. When the amount of spread polymer is in creased, the GS DHP layer shows a regular increase of the DHP volume fracti on whereas the G; DHP forms steeper density profile structures, implying th at molecular structural differences might be involved in these different be haviors.