Controlled Wettability of Polymers via Environmental Crazing

This work highlights the benefits of environmental crazing for the control over the hydrophilic-lipophilic balance of glassy amorphous and semicrystalline polymers: poly(ethylene terephthalate) (PET) and biodegradable polycaprolactone (PCL). Task-oriented encapsulation of diverse commercial and natural hydrophilic (polyethyleneoxide, polyvinylpyrrolidone, gelatin) and hydrophobic guest additives (perfluoroorgano siloxanes, water-repellent impregnation) into mesoporous host polymer (PET, PCL) matrixes allows targeted control over the wettability of the resultant nanocomposite materials. Depending on the nature of the guest additive, the properties of the modified polymers can be varied from hydrophilic to hydrophobic: contact angle (CA) of PET can be adjusted from 47⊥/38∥ to 130⊥/117∥° (for initial PET, CA=82°) and CA of PCL from 40° to 114° (for initial PCL CA=75°). The unique benefits of environmental crazing for structural modification are related to the universal character of this approach which can be applied to a broad range of polymers and allows preparation of diverse high-performance materials with tunable hydrophilic-lipophilic balance.