Hollow poly(alpha-methylstyrene) (PAMS) shows application in inertial confinement fusion experiments as the degradable mandrels of glow plasma polymer shells. However, the molecular weight of PAMS has great influence on the quality of mandrels. In this work, this influence was systematically studied using several PAMS samples with different molecular weights. For PAMS shells with 900 μm inner diameter and different wall thickness, when the molecular weight of PAMS is in the range of 300-500 kg·mol^-1, perfect sphericity and good wall thickness uniformity can be obtained. In contrast, when increasing molecular weight to 800 kg·mol ^-1, the sphericity and the wall thickness uniformity become worse. Moreover, compared with the wall uniformity, the sphericity of PAMS shells was much less sensitive to the molecular weight. The results also showed that the stability of W1/O compound droplets of PAMS shells were less affected by the molecular weight. It was revealed that the wall uniformity and the sphericity of the PAMS shells were associated with the diffusion rates of fluorobenzene (FB).

Polymer shells with high sphericity and uniform wall thickness are always needed in the inertial confined fusion (ICF) experiments. Driven by the need to control the shape of water-in-oil (W1/O) compound droplets, the effects of the density matching level, the interfacial tension and the rotation speed of the continuing fluid field on the sphericity and wall thickness uniformity of the resulting polymer shells were investigated and the spherical and concentric mechanisms were also discussed. The centering of W1/O compound droplets, the location and movement of W1/O compound droplets in the external phase (W2) were significantly affected by the density matching level of the key stage and the rotation speed of the continuing fluid field. Therefore, by optimizing the density matching level and rotation speed, the batch yield of polystyrene (PS) shells with high sphericity and uniform wall thickness increased. Moreover, the sphericity also increased by raising the oil/water (O/W2) interfacial tension, which drove a droplet to be spherical. The experimental results show that the spherical driving force is from the interfacial tension affected by the two relative phases, while the concentric driving force, as a resultant force, is not only affected by the three phases, but also by the continuing fluid field. The understanding of spherical and concentric mechanism can provide some guidance for preparing polymer shells with high sphericity and uniform wall thickness.Physics for financial support (2014B0302052) and National Natural Science Foundation of China (U1530260).

为提高惯性约束聚变（ICF）点火靶尺度（约2 mm）聚苯乙烯（PS）空心微球的球形度,研究了油相与外水相界面张力、初始油相质量分数和固化旋转流场转速对PS微球球形度的影响。结果表明,将双重乳液体系外水相中的表面活性剂聚乙烯醇（PVA）替换为聚丙烯酸（PAA）后,油相与外水相之间的界面张力增大了约10倍,PS空心微球的球形度显著提高,球形偏离度小于1 μm的微球比例由5%增加至约50%；但是,在较宽范围内改变油相初始质量分数及旋转固化流场转速,对PS微球球形度的影响并不显著,球形偏离度值小于1 μm的PS微球比例介于40%~60%之间。

在乳液微封装技术制备聚苯乙烯空心微球的工艺中，固化过程是决定微球球形度及壁厚均匀性的关键阶段。基于乳粒发生器制备内径(850±10) μm、壁厚(250±25) μm的复合乳粒，以25 ℃,45 ℃和65 ℃作为固化温度，考察了固化温度对微球球形度和壁厚均匀性的影响。结果表明，固化温度越低，界面张力越高，乳液固化速率越慢，微球球形度和壁厚均匀性越好。当固化温度为25 ℃时，批次微球中球形偏离值优于2 μm的微球产率为90%，壁厚偏差值优于2 μm的微球产率为40%，明显优于固化温度为45 ℃和65 ℃时微球的质量。

为研究分子量对聚-α-甲基苯乙烯(PAMS)空心微球的乳液微封装制备过程中乳液固化速率的影响, 实验采用分子量为300~800 kg·mol-1的3种PAMS作为油相, 测量在聚乙烯醇(PVA)和聚丙烯酸(PAA)两种外水相环境下, PAMS/氟苯(FB)乳液直径、油相浓度和FB扩散通量随固化时间的变化。结果表明, 随PAMS分子量减小, PAMS油相浓度上升趋势变慢, FB扩散通量的峰值在分子量为300 kg·mol-1时达到最小。因此, 可通过降低PAMS分子量的方式来延长乳液的固化时间, 从而降低FB的扩散速率, 使乳液有足够时间调整形变有利于获得良好的微球球形度。

在考察聚苯乙烯(PS)与聚乙烯基苄氯(PVBCl)相容性及干涉效应对测量结果影响的基础上, 使用红外显微化学图像技术研究表征了PS与PVBCl混合物薄膜和微球的相分离情况, 对比分析了不同处理条件下制备的微球半球壳中两种聚合物的相分离红外显微化学图像。研究结果表明建立的研究方法可以用来定性或半定量的分析球壳内PS和PVBCl两聚合物的分相情况, 在测试中样品的干涉效应会对测量造成较大的不确定度, 在不同温度下获得的聚合物微球样品中, 40 ℃条件下两聚合物的分相情况更为理想。该研究为探索非均相双半球型聚合物微球制备条件以及红外显微化学图像法表征聚合物相分离提供了一种直观可行的表征方法, 但受空间分辨率的影响, 该方法不适合于6.25 μm×6.25 μm以下尺寸样品的分析。

激光惯性约束聚变的核心思想是利用球形内爆技术对聚变燃料进行增压，使热核燃料达到高温、高密度的等离子体状态，进而实现聚变点火。基于对称压缩、流体界面不稳定性和实验诊断的考虑，ICF实验对作为热核燃料容器的空心微球的品质在球形度、壁厚均匀性、表面粗糙度以及掺杂水平等方面提出了严格的要求。为满足这些要求，陆续发展了乳液微封装技术、降解芯轴技术、低压等离子体聚合/掺杂技术、干凝胶玻璃微球制备技术等用于多层塑料微球和空心玻璃微球的研制。另一方面，针对ICF靶丸量小、质轻以及表面要求高的特点，发展了相应的非破坏性靶丸参数表征技术，如X光照相技术、4π形貌表征技术、微球掺杂水平测量技术以及微球内燃料负载水平快速测试技术。基于这些制备与表征技术，初步实现了多层塑料微球、玻璃微球、聚-α-甲基苯乙烯芯轴微球、梯度掺杂CH微球的研制，满足了“神光Ⅱ”、“神光Ⅲ原型”及“神光Ⅲ主机”上开展的一系列内爆物理实验的要求，同时为未来点火物理实验用靶丸的研制提供了技术支撑。

为满足惯性约束聚变(ICF)对聚酰亚胺(PI)靶丸的要求，研究了气相沉积过程单体加热温度对PI薄膜厚度的影响并测试其均匀性，测试了脉冲敲击模式下复合微球的表面质量。研究了薄膜热环化过程中的结构变化，并对所得PI薄膜进行了热稳定性分析。研究结果表明: 脉冲敲击下制备所得复合微球表面粗糙度均方根值波动在29~45 nm之间，在相同时间内其薄膜厚度随单体加热温度的增加而增加，通过调节不同单体加热温度，可将薄膜厚度控制在一定范围; 薄膜厚度测试发现其较为均匀，横向和纵向各点厚度相差不足1 μm; 热环化后聚酰胺酸转化为PI，CONH与COOH结合形成C-N键; 热重分析数据显示PI薄膜热稳定性较好，600 ℃左右才开始大量分解。

为调控固化过程中双重乳液内径的变化和降低聚-α-甲基苯乙烯(PAMS)微球的表面粗糙度，研究了双重乳液固化过程中内外水相中电解质浓度对水在油相液膜中迁移和分相行为的影响。结果表明: 仅在外水相中添加电解质时，内水相的渗透压高于外水相，使得内相水向外水相迁移，导致固化后的微球表面起皱。当在内外水相同时添加电解质时，由于平衡了三相之间水的化学势，抑制了水在油相液膜中的迁移和分相，导致PAMS微球壳壁内气泡体积和数量显著降低。同时，在内外水相中同时添加不同浓度的电解质，还可显著改善双重乳液三相之间的密度匹配度，从而提高微球的球形度和壁厚均匀性。