论文总字数：21521字

摘 要

微结构颗粒材料是指一类具有特殊的构造、可调的性质或者能够易于功能化的单组分或者多组分复合材料，可广泛应用在生物技术、纳米技术、电子技术、能源再生领域。其中以各向异性颗粒和核壳结构颗粒为典型代表。其制备方法需要根据材料自身性质的不同来选择和设计，普适性不好，无法拓展至其他性质的材料的制备。因此，近来有研究者开发基于液滴微流体技术的制备这些材料的方法，其普适性较好，并且能够制备多种形貌和性质的颗粒材料，但是其不能同时实现复杂形貌和多组分的灵活调变，并且需要复杂的微流体芯片。本文通过丙烯酰胺（AM）-聚乙二醇（PEG）水相液滴经过聚合致分相过程后形成了核壳结构的现象，有望将其用于多种形貌微结构颗粒材料的制备。

主要研究内容和结果如下。

利用液滴微流体技术研究了丙烯酰胺（AM）-聚乙二醇水相体系的聚合致分相过程，分散相是AM、交联剂、引发剂和PEG的混合水溶液，通过同轴微流体装置分散在连续相液体石蜡中形成单分散的水相液滴，液滴在延长管中的受热引发AM聚合生成PAM，PAM 与PEG 形成了分相体系。观察到液滴分相之后形成了核壳结构，将核壳液滴分散到含有Span80的液体石蜡接中得到H/W/O（hydrogel in water in oil）乳液。考察了聚合反应的温度、PEG的分子量和含量、交联剂含量和连续相流速的影响。提高反应温度，液滴内部的核会增大。增加PEG含量，液滴内部的核直径增加的同时透光性下降。PEG的分子量也会显著的影响分相过程，提高分子量，体系分相所需的PEG浓度会相应的降低。交联剂含量的提高会降低核的透光性。此外，油相的流速从1.5 mL/h 下降至0.9 mL/h，得到了棒形核的核壳液滴，并且随着油相流速的进一步降低至0.3 mL/h，棒形核的长径比从1.9增加到2.1。

关键词：微流体 聚合致分相 各向异性 核壳

ABSTRACT

Microarchitectural particles which are composed of single or multiple components and exhibit unique configurations, tailored properties and facilitatory multi-functionalization, have recently attracted increasing attention because of their promising properties for applications in biotechnology, nanotechnology, electronic technique and energy regeneration, etc. Anisotropic particles and core/shell particles are two typical examples.However the conventional synthesis methods are restricted by material properties. Hence, synthesis strategies based on droplet-based microfluidics are developed which show easily tunablility in both the morphologies and properties. The PIPS is a process in which an initially homogeneous solution of monomer and solvent becomes phase separated during the polymerization.In this dissertation, core/shell PAM/PEG droplets are obtained in microdroplets by PIPS.The mainly findings and conclusions are shown below.

The PIPS of polyacrylamide-polyethylene glycol aqueous system was studied by microfluidics. The dispersed phase was the aqueous solution of AM, PEG, crosslinker and initiator. Monodispersed droplets were formed via coaxial microfluidics device.Polymerization of acrylamide was achieved by thermal initiation. Thus the formed polyacrylamide was separated from aqueous solution of PEG. We observe that the core/shell PAM/PEG droplets were formed after polymerization. The H/W/O (hydrogel in water in oil) emulsions were obtained by dispersing the core/shell droplet into liquid paraffin (containing 5 wt% Span 80). The influences of the temperature, PEG contain and molecule weight, crosslinker contain and oil phase flow rate are examined. With increasing the polymerization temperature and the PEG content, the core size increased. In additional, core/shell droplet with a rod-liked core were obtained by decreasing the flow rate of oil phase from 1.5 to 0.9 mL/h. The aspect ratio of the rod increased from 1.9 to 2.1 as the flow rate of oil phase decreased from 0.9 to 0.3 mL/h.

KEYWORDS：Microfluidics；Polymerization induced phase separatio；Anisotropy；Core/shell

目录

摘 要 I

ABSTRACT II

第一章 文献综述 1

1.1 研究背景 1

1.2 聚丙烯酰胺微球的性质 1

1.2.1 聚丙烯酰胺（PAM）微球的性质与用途 1

1.2.2 聚丙烯酰胺（PAM）微球的制备方法 1

1. 3 液滴微流体技术简介 2

1.3.1 液滴的成型 3

1.3.2 液滴的操控 5

1.4 本文研究的目的与内容 8

第二章 实验部分 11

2.1 实验部分 11

2.1.1 原料 11

2.2 实验步骤 11

2.2.1 装置 11

2.2.2 PAM/PEG单核壳H/W/O液滴的制备 12

2.3 样品表征 14

第三章 结果与讨论 15

3.1 AM/PEG 液滴在微通道中分相现象 15

3.2 PEG-4000的含量对分相过程的影响 17

3.3 PEG分子量的影响 17

3.4 交联剂MBAM含量的影响 19

3.5 棒形核H/W/O乳液的制备 19

3.6 本章小结 20

第四章 结论 21

参考文献 23

致 谢 25

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