Entropy dominated behaviors of confined polymer-nanoparticle composites

The stretched polymers would lose their possible configurations if they are mixed with nanoparticles or touch on a hard wall, which leads to a strong depletion attraction responsible for the enrichment of nanoparticles near substrates. Moreover, it is found that there exists a sacrifice mechanism in confined pure polymer samples or polymer-nanoparticle mixtures that part of polymers in order to reach a minimum free energy for the total system, are adsorbed on hard walls even by losing their conformation. The understanding based on the current study provides a simple yet effective approach for the design of thin polymer composites.