The Effect Of Cyclodextrin On Morphology And Release Behavior Of Chitosan Microcapsule

Core-shell capsules are of particular interest to researchers,because such capsules are capable of encapsulating payloads and protecting payloads from undesirable destruction.In order to preferably control the release of payloads,more attention is being paid to stimuli-responsive capsules.Such responsive capsules can be triggered by environmental pH,temperature,ionic concentration or chemical reagent,and they show excellent ability in controlling the release rate.In this article,chitosan microcapsules that show a stimuli response to cyclodextrin have been introduced.In addition,this article attempts to prepare polymer microspheres with excellent properties using a microfluidic device.This article described a new and simple method to control the release of payloads encapsulated in chitosan microcapsules.The chitosan microcapsule with the liquid core and rigid shell was performed by drop-wisely adding chitosan solution into anionic surfactant solution.We found that the microcapsule showed a stimuli response to?-cyclodextrin??-CD?.The microcapsule was destroyed by?-CD,because?-CD bound and sequestered surfactant from the shell through the host-guest interaction.The destruction process was studied by optical microscopy and scanning electron microscopy.The microcapsule swelled in acid solution and shrank in alkaline solution.It was found that the destruction speed of the microcapsule increased with increasing acidity or alkalinity of?-CD solution.Rhodamine B encapsulated in the liquid-core of chitosan microcapsule was released from the microcapsule in?-CD solution.The release rate was adjusted by the pH value and the concentration of?-CD solution.The release speed of the microcapsule increases with the increase of acidity or alkalinity in?-CD solution.The release speed of microcapsule treated by?-CD is more serious than that treated by?-CD in the same treatment time.The second part of the work introduced a novel method to prepare polymer microspheres.Firstly,poly?methyl methacrylate-co-butyl acrylate??PMMA-co-BA?emulsion was synthesized by using sodium dodecyl benzene sulfonate?SDBS?as an emulsifier.Then,polymer microspheres were prepared through a microfluidic device.When concentration of polyvinyl alcohol was 2.5%in the emulsion,the receptor liquid was the mixture of 1wt%chitosan with low viscosity and 1wt%CaCl₂,gas flow rate was 0.3 L/min,the prepared microspheres showed the best morphology and size distribution.Microspheres containing sodium fluorescein showed a stable fluorescent property for a long time.