Study on the impact of photoaging on the generation of very small microplastics (MPs) and nanoplastics (NPs) and the wettability of plastic surface

A review on photochemical effects of common plastics and their related applications

“…[241][242][243][244][245][246] More importantly, rough surfaces are more conducive to adhesion of other contaminants or microorganisms. 228,229,247 For instance, Li et al found that the adsorption of Cr (VI) on the aged microplastics was also significantly enhanced based on the surface physicochemical properties of the microplastics, surface complexation and van der Waals forces. 248 In addition, Yu et al also found that the adsorption capacity of aged microplastics was higher than that of pristine microplastics, and their physical interactions, including partitioning, electrostatic interactions, and intermolecular hydrogen bonding, were the dominant mechanism.…”

“…250 Based on our previous work and according to the change in direction of plastic surface wettability under light irradiation, the photochemical effects of plastics can be divided into photoaging effect and UV irradiation-surface reconstruction effect. 247,251 For one thing, as is shown in Figure 12, photoaging often causes most plastic surface to change from hydrophobic to hydrophilic due to the introduction of oxygen-containing functional groups such as hydroxyl and carboxyl groups in the process of light irradiation. 247 For another thing, the polymer molecules on the surface of most polymer materials actually lack restriction and are independent of each other.…”

“…247,251 For one thing, as is shown in Figure 12, photoaging often causes most plastic surface to change from hydrophobic to hydrophilic due to the introduction of oxygen-containing functional groups such as hydroxyl and carboxyl groups in the process of light irradiation. 247 For another thing, the polymer molecules on the surface of most polymer materials actually lack restriction and are independent of each other. Thus, macromolecules on the surface of polymers have considerable fluidity and these molecules with high degrees of freedom on the surface of polymer materials often migrate and flip, resulting in great changes in the properties of the surface of polymers.…”

“…On the contrary, if a certain type of plastic (usually containing benzene rings) is prone to transition from hydrophobicity to hydrophilicity under the influence of photoaging, this type of plastic is more likely to maintain hydrophilicity after photoaging. 247,251…”

“…120 Furthermore, it has certain reference significance for catalytic degradation of plastics and hydrophilic modification of plastic surface. 247 Besides, some temperature-and light-responsive intelligent polymer materials can be developed. 280…”