Abstract: Different from the aggregation-caused quenching (ACQ) effect of traditional fluorescent dyes, aggregation-induced emission (AIE) dyes have become a research hotspot in recent years due to their unique luminescence behavior. The applications of AIE polymer nanoparticles (AIE-PNPs) have gradually expanded from the fields such as cell imaging and chemical sensing to textile printing and dyeing fields. The research on ACQ-PNPs has been ignored for a long period. It is undeniable that a large number of ACQ dyes such as Nile red (NR) and fluorescein possess advantages of stable photophysical chemical properties, high quantum yield and so on, although the fluorescence of dyes would be weaken even quenched when the concentration reaches a certain value. Additionally, not all fluorescent polymer nanoparticles (FPNPs) need to load dyes at a high concentration in many practical applications. Therefore, it is of great importance to conduct in-depth analysis of the discrepancies of the luminescence performance between ACQ-PNPs and AIE-PNPs, and to explore the practical application value of ACQ-PNPs and AIE-PNPs simultaneously.
Enjoying the advantages of green, simple and efficient preparation process, miniemulsion polymerization technology can be used to prepare various FPNPs flexibly. To compare and analyze the luminescent properties of ACQ-PNPs and AIE-PNPs, and further explore their applications in inkjet printing, PMMA/NR NPs and PMMA/TPE NPs were prepared through encapsulation of ACQgen dyes, NR and AIEgen dyes, tetraphenylethylene (TPE) in water-borne miniemulsions, respectively. Influences of the amount of dyes on the final monomer conversion, particle size and luminescent properties of PMMA/NR and PMMA/TPE NPs were investigated and analyzed. The results show that the maximum content of NR and TPE dyes is 1.5wt% and both NR and TPE dyes have negligible influence on the final monomer conversion and particle size. Within the range of 0–1.5% of fluorescent dyes, the photoluminescence (PL) intensity of PMMA/NR NPs shows a trend of first increasing and then maintaining unchanged with the increase of NR content, without fluorescence weakening or quenching phenomenon, whereas the PL intensity of the PMMA/TPE NPs increases linearly with the increase of TPE content. When the content of florescent dyes is higher than 1.5%, the PL intensity of PMMA/NR NPs begins to decrease while that of PMMA/TPE NPs keeps increasing with the increase of the fluorescent dye’s content. Therefore, the critical concentration of dyes to avoid the weakening of fluorescence of PMMA/NR NPs is 1.5%. Furtherly, in order to improve the film-forming and inkjet printing performance of FPNPs, poly(MMA-co-20%BA)/NR and poly(MMA-co-20%BA)/TPE NP emulsions were prepared through miniemulsion polymerization at 1.5% content of fluorescent dyes. After diluting, adding surfactants and filtering, poly(MMA-co-20%BA)/NR and poly(MMA-co-20%BA)/TPE NP inks were prepared and used for inkjet printing on cotton fabrics. Under incandescent light, the printed fabrics with poly(MMA-co-20%BA)/NR and poly(MMA-co-20%BA)/TPE NP inks display the same appearance as the pristine fabric, but display a bright red and blue pattern under UV light, respectively. 
This paper unveils the relationship of the amount of dyes and luminescent properties of ACQ-PNPs and AIE-PNPs, and further demonstrates both NR-based ACQ-PNPs and TPE-based AIE-PNPs emulsion prepared through miniemulsion polymerization have great potential in inkjet printing application with a suitable amount of fluorescent dyes. Research results can provide reference for the development of photochromic inkjet ink.

Key words: aggregation-induced emission, aggregation-caused quenching, polymeric nanoparticles, miniemulsion polymerization, luminescent properties, inkjet printing

摘要： 为探究聚集诱导猝灭（ACQ）型和聚集诱导发光（AIE）型聚合物纳米粒子（PNPs）的发光性能，以及二者在喷墨印花中的应用效果，采用细乳液聚合技术原位包覆ACQ染料尼罗红（NR）和AIE染料四苯基乙烯（TPE），制得ACQ-PNPs和AIE-PNPs。采用重量法、动态光散射、扫描电镜、紫外-可见分光光度法和荧光光谱法等研究了染料用量对PMMA/NR NPs和PMMA/TPE NPs的最终转化率、颗粒特征和发光性能的影响；将poly(MMA-co-20%BA)/NR NPs和poly(MMA-co-20%BA)/TPE NPs乳液配制成墨水，用于棉织物的喷墨打印，探究两类墨水在棉织物上的喷墨印花效果。结果表明：当染料质量分数低于1.5%时，NR和TPE染料对PMMA/NR NPs和PMMA/TPE NPs体系聚合反应最终转化率和纳米粒子尺寸影响均较小，PMMA/NR NPs荧光强度随NR染料质量分数的增加呈现先增加后趋于稳定的趋势，而PMMA/TPE NPs荧光强度与TPE染料近乎呈线性正相关。此外，经poly(MMA-co-20%BA)/NR和poly(MMA-co-20%BA)/TPE NPs墨水喷墨打印后的棉织物，其图案分别呈现出明亮的红色和蓝色荧光。研究表明，在合适的染料浓度范围内，采用细乳液聚合法制得的ACQ和AIE聚合物纳米粒子乳液在喷墨印花领域中均有良好的应用前景。

关键词: 聚集诱导发光, 聚集荧光猝灭, 聚合物纳米粒子, 细乳液聚合, 发光性能, 喷墨印花