乳液/悬浮电纺制备微纳米结构及控制

Emulsion electrospinning combining suspension electrospinning, that is, emulsion/suspension electrospinning, leads the way to an easy and green method for electrospinning. The research in terms of emulsion/suspension electrospinning has been focus on drug delivery and related applications. However, the relationship between the electrospinning process conditions (the electric field, the solution concentration and etc.) and the micro/nano-structure of electrospun product has not been studied extensively and intensively.. Emulsion electrospinning offers many advantages, in particular for drug encapsulation and thereby modification of drug release. One of the reasons of using emulsion electrospinning technique is to overcome the challenge of incorporation and sustained release of the hydrophilic bioactive molecules, such as drugs etc. from hydrophobic polymer nanofibers. However, emulsion electrospinning still is a concept which makes use of toxic and/or flammable organic solvents either as a continuous phase (W/O emulsion) or as a separated phase (O/W emulsion). This could hinder the development for large scale productions and could be critical for in vivo medical applications and in many other areas such as agriculture. This demands a need for further solutions regarding electrospinning of polymers only from water and if possible. Suspension electrospinning could solve the problem mentioned above. Thus, emulsion electrospinning together with suspension electrospinning, should be a potential and meaningful field and be worth carrying out a thorough research.. Our objective is to find out the optimum conditions concerning with electrospinning and then to point out the relationship between the conditions and the micro/nano-structure of the product. Moreover, the mechanism how the the micro/nano-structure of the product in emulsion/suspension electrospinning work out, should be explained. In recent years, the electrospinning technique and its applications have been studied and we have got some interesting results. Sample analysis instruments includes scanning electron microscopy, X-ray diffraction (XRD), fourier transform infrared instrument, differential thermal and etc. So our team has required conditions in this applied project. Moreover, several research groups and our team maintain a long-term cooperation in terms of related research and thus a convenient sample analysis could be available.

乳液/悬浮液电纺是简易、绿色环保的电纺方法。目前，乳液/悬浮电纺研究主要集中在药物控释材料的制备和应用方面，在乳液/悬浮电纺工艺参数与最终产物的微纳米结构之间的关系有待进一步研究。本申请通过对部分乳液/悬浮体系（如核壳乳液）进行电纺研究，充分考察乳液/悬浮液本身属性（乳液固含量、助纺剂、表面活性剂的种类及含量等）及电纺过程参数（电压和分散液配比等）对产物的微纳米结构的影响，研制出各种形态的微纳米结构。并同时开展工艺参数与产物微纳米结构参数的关联及机理研究。将SEM、XRD、XPS等测试仪器得到的物理和化学信息进行系统分析，建立起参数变化和产物微纳米结构变化的一一对应关系。合理的提出 "微纳米结构-电纺条件"机理或机制相关假设。通过研究，期望得到更有实际应用价值的微纳米级的纤维或结构，并且实现一定程度上产物微纳米结构的可控，为乳液/悬浮电纺的应用及产品开发奠定理论与实验基础。

本项目通过对部分乳液/悬浮体系（如核壳乳液）进行电纺研究，充分考察乳液/悬浮液本身属性（乳液固含量、助纺剂、表面活性剂的种类及含量等）及电纺过程参数（电压和分散液配比等）对产物的微纳米结构的影响，研制出各种形态的微纳米结构。通过研究，实现了的电纺微纳米级的纤维或结构地控制，具体如下：.1. 表面活性剂决定电纺丝混合液的稳定性的关键性因素，研究发现表面活性剂含量在3%~7%时，才能配制成均一稳定的纺丝液；电纺纤维的微观结构通过调节PS/PVA配比实现其可控性，随着PVA含量的降低，电纺纤维的微观结构由光滑无串珠的丝状结构，逐步转变串珠结构、纺锤状的串珠结构、带孔的球（或半球）串珠结构。.2. 利用较软的苯丙无规共聚物（PSBA）制备了弹性较好的纤维结构，解决了较硬的PS乳胶粒子有序堆积于纤维中形成纤维膜较脆的问题。纺丝电压在一定程度上影响纤维的形貌与尺寸；调控纺丝液PSBA/PVA配比可获得可控性的纤维结构。.3. 利用苯丙核壳粒子外层柔软，核硬的特点，制备软硬适中的电放纳米纤维，得到性能优良的具有精细微观结构的纳米纤维膜材料。对比聚苯乙烯与不同苯丙乳液体系聚合物所得电纺纤维的表面形貌发现，利用具有较高Tg的聚合物电纺可得到表面粗糙的玉米粒型纤维，而利用具有较低Tg的聚合物电纺可得到表面光滑的纤维。