We propose a new way of regulating protein adsorption by using a pH-responsive polymer. According to the the- oretical results obtained from the molecular theory and kinetic approaches, both thermodynamics and kinetic...We propose a new way of regulating protein adsorption by using a pH-responsive polymer. According to the the- oretical results obtained from the molecular theory and kinetic approaches, both thermodynamics and kinetics of protein adsorption are verified to be well controlled by the solution pH. The kinetics and the amount of adsorbed proteins at equi- librium are greatly increased when the solution environment changes from acid to neutral. The reason is that the increased pH promotes the dissociation of the weak polyelectrolyte, resulting in more charged monomers and more stretched chains. Thus the steric repulsion within the polymer layer is weakened, which effectively lowers the barrier felt by the protein during the process of adsorption. Interestingly, we also find that the kinetics of protein desorption is almost unchanged with the variation of pH. It is because although the barrier formed by the polymer layer changes along with the change of pH, the potential at contact with the surface varies equally. Our results may provide useful insights into controllable protein adsorption/desorption in practical applications.展开更多
Free radical co-polymerization was employed to synthesize co-poly carboxylate (PC) su-perplasticizers with different amount of carboxyl and methyl polyethylene glycol (MPEG) side chain. Dispersion ability and retentio...Free radical co-polymerization was employed to synthesize co-poly carboxylate (PC) su-perplasticizers with different amount of carboxyl and methyl polyethylene glycol (MPEG) side chain. Dispersion ability and retention of PC were compared with one another. The results show that increase of side chain is advantageous to dispersion, but it decreases when amount of MPEG is beyond a certain value which is different with the proportion of carboxyl. If the amount of carboxyl increases, the influence of side chain in copolymer on dispersion diminishes. Polyether side chain is advantageous to retention. And the author explained the mechanism of PC using the theory of steric repulsive force.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.21274062,11474155,and 91027040)
文摘We propose a new way of regulating protein adsorption by using a pH-responsive polymer. According to the the- oretical results obtained from the molecular theory and kinetic approaches, both thermodynamics and kinetics of protein adsorption are verified to be well controlled by the solution pH. The kinetics and the amount of adsorbed proteins at equi- librium are greatly increased when the solution environment changes from acid to neutral. The reason is that the increased pH promotes the dissociation of the weak polyelectrolyte, resulting in more charged monomers and more stretched chains. Thus the steric repulsion within the polymer layer is weakened, which effectively lowers the barrier felt by the protein during the process of adsorption. Interestingly, we also find that the kinetics of protein desorption is almost unchanged with the variation of pH. It is because although the barrier formed by the polymer layer changes along with the change of pH, the potential at contact with the surface varies equally. Our results may provide useful insights into controllable protein adsorption/desorption in practical applications.
文摘Free radical co-polymerization was employed to synthesize co-poly carboxylate (PC) su-perplasticizers with different amount of carboxyl and methyl polyethylene glycol (MPEG) side chain. Dispersion ability and retention of PC were compared with one another. The results show that increase of side chain is advantageous to dispersion, but it decreases when amount of MPEG is beyond a certain value which is different with the proportion of carboxyl. If the amount of carboxyl increases, the influence of side chain in copolymer on dispersion diminishes. Polyether side chain is advantageous to retention. And the author explained the mechanism of PC using the theory of steric repulsive force.
