We have developed a model containing clustered peptide chains to evaluate coupling difficulties associated with interchain interactions in solid phase peptide synthesis. Our results revealed two new findings. First, there was a significant difference in solvation properties between the conventional dispersed and our clustered peptide chain models at a similar level of peptidyl loading. At the completion of an eight-residue peptide, with a peptide content of >61%, the solvated volumes of a dispersed chain model increased 20-30-fold over the initial dry resin and were about 4-5-fold higher than those of the clustered chain model in both polar and nonpolar solvents.