Surface modification enables fiber lubrication and processing but little is known about the extent and dynamics of adsorption of typical adsorbates applied for such purposes, which often includes water-soluble block nonionic amphiphilic polymers. In this work we used quartz crystal microgravimetry (QCM) to investigate the adsorption on poly(ethylene terephthalate) (PET) of polyalkyl glycol ethers and triblock molecules of ethylene oxide and propylene oxide. The adsorption from aqueous solution of the block nonionic amphiphilic polymers strongly correlated with the self-association driven by the chain length of the respective hydrophobic blocks. This was demonstrated for the different adsorbing polymers using hydrophobic numbers calculated from simple group contribution methods. Hydrophobic and van der Waals interactions explain the affinity of the nonionic polymers with PET, which lead to adsorption isotherms that follow Langmuir-based and one-step empirical adsorption models. (C) 2014 Elsevier Inc. All rights reserved.