The diffusion, size and location of added silver grains in the cell walls of Swedish pine, Pinus sylvestris

The size and location of silver particles in K-glycerate/AgNO3 impregnated Swedish pine, green wood as well as high temperature dried, have been studi ed using TEM micrographs. The diameter of the silver particles was found to be 2-20 nm in the impregnated green wood and as large as 1000 nm (major ax is) for the ellipsoid-shaped silver clusters in the impregnated dried wood. Studying the projected area of the silver particles in impregnated green w ood indicated that there are a lot of particles (40%) in the compound middl e lamella with fewer particles in the St (6-8%), S-1 (4%) and S-3 (2%) laye rs. The average distance between the silver particles, 50 nm (S-2-layer), i n impregnated green wood shows that the impregnant is distributed in the ce ll wall at the microfibrilar level. Experimental results show that the fast est diffusion path into the cell. wall is from the lumen over the pit membr ane through the compound middle lamella and not from the lumen through the secondary wall layer S-3.