RAFT聚合制备PMPS-b-PNIPAM嵌段共聚物及温敏性纳米粒子

doi:10.11949/0438-1157.20190342

摘要/Abstract

摘要：

利用可逆加成-断裂链转移(RAFT)活性自由基聚合合成了一系列分子量可控、分子量分布窄的甲基丙烯酸-3-三甲氧基硅丙酯(MPS)和N-异丙基丙烯酰胺(NIPAM)的嵌段共聚物，在水溶液中分散制备温敏性的含硅纳米粒子。保持疏水链段PMPS的长度恒定，改变亲水链段PNIPAM的长度，在不同pH的水溶液中进行实验，研究亲水链段长度、pH对聚合物的临界聚集浓度、纳米粒子的尺寸和形貌以及温度变化过程中的相分离行为的影响，得到尺寸较小、溶液稳定的温度响应性含硅纳米粒子，同时具有有机物和无机物的优良特点，在生物医学、化学催化、纳米反应器、染料涂料等多领域具有广泛的应用前景。

关键词: 共聚物, 硅烷, 纳米粒子, pH, 水解

Abstract:

A series of molecular weight-controlled, narrow molecular weight distributions of 3-trimethoxysilyl methacrylate (MPS) and N-isopropyl acrylamide (NIPAM) block copolymers were synthesized by reversible addition-fragmentation chain transfer (RAFT) living radical polymerization. Temperature-sensitive silicon-containing nanoparticle are prepared by dispersing in aqueous solution. With the same chain length of hydrophobic segment PMPS, by changing the chain length of hydrophilic segment PNIPAM and the pH of the water solutions, the critical aggregation concentrations, the diameters and morphologies of the nanoparticles, and the phase separation behavior happening in the process of temperature variation were studied. Thermo-responsive and spherical nanoparticles were attained. The nanoparticles possessed advantages of both organics and inorganics. And they may have wide applications in many fields such as biomedicine, chemical catalysis, nanoreactors, dyes, coatings and so on.

Key words: polymers, silicane, nanoparticles, pH, hydrolysis

中图分类号:

TQ 316.344

赵小燕, 单国荣. RAFT聚合制备PMPS-b-PNIPAM嵌段共聚物及温敏性纳米粒子[J]. 化工学报, 2019, 70(10): 4080-4088.

Xiaoyan ZHAO, Guorong SHAN. PMPS-b-PNIPAM copolymers synthesized by RAFT polymerization and their thermo-responsive nanoparticles[J]. CIESC Journal, 2019, 70(10): 4080-4088.

图/表 13

图1 RAFT聚合制备PMPS-b-PNIPAM嵌段共聚物反应过程

Fig.1 Reaction process of MPS and NIPAM RAFT copolymerization

表1 PMPS以及PMPS-b-PNIPAM嵌段共聚物的分子量和分子量分布

Table 1 Molecular weight and its distribution of PMPS and PMPS-b-PNIPAM block copolymers

Sample	$M n ˉ$ ^①	$M n ˉ$	PDI
PMPS	2800	2700	1.19
M10N10^②	4000	4100	1.68
M10N30^②	6400	6500	1.53
M10N50^②	8700	8500	1.32

表1 PMPS以及PMPS-b-PNIPAM嵌段共聚物的分子量和分子量分布

Table 1 Molecular weight and its distribution of PMPS and PMPS-b-PNIPAM block copolymers

Sample	$M n ˉ$ ^①	$M n ˉ$	PDI
PMPS	2800	2700	1.19
M10N10^②	4000	4100	1.68
M10N30^②	6400	6500	1.53
M10N50^②	8700	8500	1.32

图2 PMPS-b-PNIPAM嵌段共聚物的凝胶渗透色谱图

Fig.2 GPC curves of PMPS-b-PNIPAM block copolymers

图3 PMPS-b-PNIPAM嵌段共聚物的1H NMR谱图

Fig.3 1H NMR spectra of PMPS-b-PNIPAM block copolymers

表2 PMPS-b-PNIPAM嵌段共聚物核磁谱图部分峰面积比值

Table 2 Ratio of peak areas in 1H NMR curves of PMPS-b-PNIPAM block copolymers

Sample	Ratio of peak areas of [—CH₂ —CH—,—CH₂—CH— and —CH₂ —C— in main chain] and [—CH₃ in PMPS]		Ratio of peak areas of [—CH(CH₃ )₂ in PNIPAM] and [—CH₃ in PMPS]
Sample	Calculated data	Theoretical data	Calculated data	Theoretical data
M10N10	1.90	1.67	2.32	2.00
M10N30	4.57	3.67	5.54	6.00
M10N50	5.90	5.67	9.37	10.00

图4 不同pH条件下芘激发光谱在339 nm和333 nm处峰强度的比值随PMPS-b-PNIPAM嵌段共聚物浓度的变化

Fig.4 Intensity ratio (I 339/I 333) of pyrene measured by fluorescence spectroscopy as function of PMPS-b-PNIPAM copolymers concentration in different pH solutions

表3 不同条件下聚合物的临界聚集浓度

Table 3 CAC of PMPS-b-PNIPAM copolymers in different environments

Sample	CAC/(mol/L)
Sample	NaOH	H₂O	HCl
M10N10	9.40×10^-6	19.10×10^-6	42.23×10^-6
M10N30	4.21×10^-6	11.68×10^-6	25.35×10^-6
M10N50	2.10×10^-6	5.56×10^-6	12.71×10^-6

表4 不同条件下纳米粒子的尺寸

Table 4 Average nanoparticle size in different environments/nm

Sample	H₂O		NaOH(10^-3mol/L)		HCl(10^-3mol/L)
Sample	15℃	60℃	15℃	60℃	15℃	60℃
M10N10	193	158.5	103.8	90.91	—	—
M10N30	212.7	147.1	145.3	98.14	—	—
M10N50	328.8	63.82	226.2	127.9	314.4	—

图5 不同pH条件下纳米粒子溶液的透光率随温度变化曲线

Fig.5 Optical transmittance changes of nanoparticles in different pH solutions

图6 水溶液中含Si纳米粒子的TEM图

Fig.6 TEM photographs of nanoparticles in water solution

图7 NaOH溶液中含Si纳米粒子的TEM图

Fig.7 TEM photographs of nanoparticles in NaOH solution

图8 HCl溶液中M10N50含Si纳米粒子的TEM图

Fig.8 TEM photograph of M10N50 nanoparticles in HCl solution

图9 PMPS-b-PNIPAM形成纳米粒子的机理

Fig.9 Formation mechanism of PMPS-b-PNIPAM nanoparticles

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