Poly(L-lactic acid) (PLLA) has been extensively used in tissue engineering, in which its surface hydrophilicity plays an important role. In this work, an efficient and green strategy has been developed to tailor surface hydrophilicity via alkali hydrolysis. On one hand, the ester bond in PLLA has been cleaved and generates carboxyl and hydroxyl groups, both of which are beneficial to the improvement of hydrophilicity. On the other hand, the degradation of PLLA increases the roughness on the film surface. The resultant surface wettability of PLLA exhibits crucial dependence on its crystallinity. In the specimen with high crystallinity, the local enrichment of terminal carboxyl and hydroxyl groups in amorphous regions accelerates the degradation of ester group, producing more hydrophilic groups and slit valleys on film surface. The enhanced contact between PLLA and water in aqueous solution (i.e., the Wenzel state) contributes to the synergistic effect between generated hydrophilic groups and surface roughness, facilitating further degradation. Consequently, the hydrophilicity has been improved significantly in the high crystalline case. On the contrary, the competition effect between them leads to the failure of this strategy in the case of low crystallinity.

Using a hybrid simulation approach that combines a lattice-Boltzmann method for fluid flow and a molecular dynamics model for polymers, we investigate the inertial migration of star-like and crew-cut polymer micelles in a square microchannel.

Grand-canonical Monte Carlo simulations were carried out to investigate the adsorption and separation of the binary mixture of CO₂, SO₂, and H₂S in neutral and charged armchair single-walled carbon nanotubes (SWCNTs) at low pressures and 303 K. SWCNTs with diameter of 2.17, 2.71, and 3.26 nm and intertube distance of 1.0 nm were modeled. Fixed charges of −0.04 e to +0.04 e were placed on each nanotube carbon to investigate the effect of charge. It is found that the behaviors of CO₂, SO₂, and H₂S as a component of the mixture in charged SWCNTs basically obey the same rules as they behave as pure gases. Due to the additional strong Coulomb force between the adsorbate and the charged SWCNTs, the adsorption quantity of the polar molecule (SO₂ or H₂S) are enhanced remarkably when mixed with CO₂, while the adsorption of CO₂ is usually suppressed as a result of adsorption competition in a limited space. As for the case of the mixture of SO₂ or H₂S, either of them can be enhanced or suppressed in the adsorption competition, depending on the sign of SWCNT charge.