A thermo-responsive core-shell microcapsule with a porous membrane and poly (N-isopropylacrylamide) (PNIPAM) gates was prepared using interfacial polymerization to prepare polyamide core-shell microcapsules, and plasma-graft pore-filling polymerization to graft PNIPAMinto the pores in the microcapsule wall. The proposed thermo-responsive microcapsule could be a positive thermo-response controlled-release one or a negative thermo-response one by changing the PNIPAM graft yield. When the graft yield is low, the release rate from the microcapsules is higher at temperatures above the lower critical solution temperature (LCST) than that below the LCST, due to the opened/closed pores in the microcapsule membranes controlled by the PNIPAM gates. In contrast, when the graft yield is high, the release rate is lower at temperatures above the LCST than that below the LCST, due to the hydrophilic/hydrophobic phase transition of the PNIPAM gates.

Experimental investigations on the Shirasu-porous-glass (SPG)-membrane emulsification processes for preparing monodisperse core-shell microcapsules with porous membranes were carried out systematically. The results showed that, to get monodisperse oil-in-water (O/W) emulsions by SPG membrane emulsification, it was more important to choose an anionic surfactant than to consider hydrophile-lipophile balance (HLB) matching. Increasing the viscosity of either the disperse phase or the continuous phase or decreasing the solubility of the disperse phase in the continuous phase could improve both the monodispersity and the stability of emulsions.With increasing monomer concentration inside the disperse phase, the monodispersity of emulsions became slightly worse and the mean diameter of emulsions gradually became smaller. Monodisperse monomer-containing emulsions were obtained when the SPG membrane pore size was larger than 1.0

The pore size and permeability control of a glucose-responsive gating membrane with plasma-grafted poly (acrylic acid) (PAAC) gates and covalently bound glucose oxidase (GOD) enzymes were investigated systematically. The PAAC-grafted porous polyvinylidene fluoride (PVDF) membranes with a wide range of grafting yields were prepared using a plasma-graft pore-filling polymerization method, and the immobilization of GOD was carried out by a carbodiimide method. The linear grafted PAAC chains in the membrane pores acted as the pH-responsive gates or actuators. The immobilized GOD acted as the glucose sensor and catalyzer; it was sensitive to glucose and catalyzed the glucose conversion to gluconic acid. The experimental results showed that the glucose responsivity of the solute diffusional permeability through the proposed membranes was heavily dependent on the PAAC grafting yield, because the pH-responsive change of pore size governed the glucose-responsive diffusional permeability. It is very important to design a proper grafting yield for obtaining an ideal gating response. For the proposed gating membrane with a PAAC grafting yield of 1.55%, the insulin permeation coefficient after the glucose addition (0.2mol/l) was about 9.37 times that in the absence of glucose, presenting an exciting result on glucosesensitive self-regulated insulin permeation.