γ-FeOOH-g-PDMAEMA稳定的Pickering乳液及其响应性能

Preparation and responsive properties of γ-FeOOH-g-PDMAEMA stabilized Pickering emulsion

以FeSO4·7H2O为原料,2-溴代异丁酸为表面改性剂,加入乙二胺调节pH=9,得到表面含引发剂的γ-FeOOH纳米粒子(γ-Fe OOH-Br);采用表面引发的原子转移自由基聚合法(SI-ATRP),在γ-FeOOH-Br纳米粒子上接枝具有双重响应型的聚甲基丙烯酸N,N-二甲基氨基乙酯(PDMAEMA),得到γ-Fe OOH-g-PDMAEMA纳米粒子刷;以其为Pickering乳化剂,制备了双重响应型的Pickering乳液。通过SEM、TEM、FT-IR、TGA、Zeta电位及粒径对产物进行了表征;考察了粒子刷稳定的Pickering乳液的稳定性、pH和温度响应性能。结果表明:γ-Fe OOH-Br及γ-Fe OOH-g-PDMAEMA均为针状,γ-FeOOH-Br长700nm、宽50nm,γ-Fe OOH-g-PDMAEMA的长宽分别增加到710和80nm。γ-Fe OOH-g-PDMAEMA乳化剂的低临界溶解温度(LCST)为35℃,制备的Pickering乳液稳定性好,具有可逆的pH及温度双重响应行为。

Initiator immobilizedγ-Fe OOH nanoparticles(γ-FeOOH-Br)were prepared by using FeSO4·7 H2 O as precursor,2-bromoisobutyric acid as surface modifier with the aids of ethylenediamine under p H=9.Subsequently,double-responsive poly(2-(dimethylamino)ethyl methacrylate)(PDMAEMA)was grafted fromγ-Fe OOH-Br nanoparticles by surface initiated atomic transfer radical polymerization(SI-ATRP)method to obtainγ-FeOOH-g-PDMAEMA particle brushes,which were further used as a solid particle emulsifier to prepare Pickering emulsion.The obtained products were characterized systematically by SEM,TEM,FT-IR,TGA,Zeta potential,and particle size analyzer.The stability,p H and temperature response of particle brushes stabilized Pickering emulsion were studied.The results showed that the morphologies of bothγ-Fe OOH-Br andγ-Fe OOH-g-PDMAEMA were needle-like.The size ofγ-Fe OOH-Br was 700 nm long and 50 nm wide,and the length and width ofγ-FeOOH-g-PDMAEMA were increased to 710 and 80 nm,respectively.γ-FeOOH-g-PDMAEMA emulsifier had a low critical solution temperature(LCST)of 35℃.The as-prepared Pickering emulsions were highly stable and demonstrated reversible pH and temperature dual responsive behaviors.