Influence of geometric factors of the substrate on hydrophilic surface modification of polyurethane sponges by plasma treatment

The surface modification by plasma treatment occurs by consecutive processes of excitation of gas(es) and deexcitation of excited species. The deexcitation occurs primarily at the surface yielding chemical modification of the surface (nonpolymer‐forming plasmas) or deposition of material (polymer‐forming plasma) on the substrate surface. Because of this sequence, geometric factors of the substrate in relation to the surrounding plasma phase have crucial influence on the effectiveness of plasma treatments. Simple mathematical models were developed to illustrate the effect of geometric factors involved in plasma treatments, and experimental results obtained with porous polyurethane sponges in various sizes were examined by the mathematical models for both plasma treatments by O₂, H₂O, and NH₃ and plasma polymerization of acrylic acid.