Photoinitiated polymerization of beta-cyclodextrin-stabilized Pickering high internal phase emulsion for preparation of polymethacrylate microsphere and its adsorption towards dyes

Microsphere polymer material finds a wide range of applications in fields such as adsorbent, drug carrier, catalyst and coating, and receives continuous attention. We here report a novel strategy of quick synthesis of polymethacrylate microsphere via photoinitiated polymerization of methacrylate monomer in a high internal phase emulsion (HIPE). A low cost and environmentally friendly natural product of β-cyclodextrin (β-CD) has been directly used as Pickering emulsifier to stabilize the methacrylate monomer in water to prepare the HIPE. The factors to control the particle size such as the dosage of β-CD, volume fraction of monomer internal phase and amount of inert diluting solvent, have been investigated in detail. Meanwhile, the approach has been validated by using various methacrylate monomers. Our results indicate that using a diluting solvent can not only change the surface morphology but also control the inner microstructure of the microsphere. By using a poor solvent of cyclohexane as diluting agent, porous microsphere other than solid microsphere has been prepared, and it could be directly applied as adsorbent to decolor oil. Moreover, the obtained poly(glycidyl methacrylate) microsphere was post-modified to exhibit satisfactory adsorption efficiencies towards organic dye contaminates in water. Those results indicate powerful platform of the obtained microsphere with reactive groups for further modification to prepare functional materials for desired purposes. Based on the fast synthesis, high yield, low energy cost as well as no harmful waste, the preparation strategy reported in this work could be scalable, and the obtained microsphere may find promising potential applications. Graphical abstract