基于DMD数字掩模的光引发表面ATRP制备聚乙二醇聚合物刷微图案

Fabrication of Micropatterned Poly( ethylene glycol) Brushes via Photo-Initiated Surface Atom Transfer Radical Polymerization Under DMD Digital Mask Projection

以基于数字微镜器件(DMD)的数字掩模技术为基础,以三(2-苯基吡啶)合铱(Ir(ppy)3)为光氧化还原催化剂,以低聚(乙二醇)甲基丙烯酸酯为单体,通过光引发表面原子转移自由基聚合(ATRP)在硅片表面实现了复杂图案形状聚乙二醇(PEG)聚合物刷微图案的快速制备(小于10 min)。原子力显微镜(AFM)和光学显微镜测试结果表明该方法能够实现最小10μm图形线宽的PEG聚合物刷微图案,且聚合物刷厚度和图形精度受到催化剂浓度、单体浓度的影响。综合考量聚合物刷厚度与图形精度,优选的催化剂浓度为1. 22 mmol/L,单体浓度为1. 22 mol/L。激光共聚焦显微镜表征异硫氰酸荧光素(FITC)染色牛血清蛋白在PEG聚合物刷微图案表面的吸附结果表明,所得PEG聚合物刷微图案能够在硅片表面实现不同区域的非特异性抗蛋白吸附反差。

Using digital micro-mirror device（DMD）-based digita! mask for light mediation, photo-initiated surface atom transfers radical polymerization （ATRP） was introduced to prepare complicated poly （ethylene glycol） （PEG） brushes micropatterns on silicon substrates （less than 10 min）, with Ir（ppy）3 as photo-redox catalyst and oligo （ethylene glycol） methacrylate （OEGMA） as monomer. X-ray photoelectron spectroscopy （XPS） characterization was conducted to verify the chemical Composition of silicon substrates, establishing the comb-structure of obtained PEG brushes. Optical microscopy and atomic force microscope （AFM） were applied to investigate the thickness and dimension of micropatterned PEG brushes corresponding to different Catalyst concentrations and monomer concentrations. A minimum width of 10 υm for stripe-shaped PEG brushes micropattern is observed under a stripe- shaped digital mask projection with two-pixel width （7.6 /υm）. The correlation between digital mask design and obtained micropattern dimension features is revealed in form of dimensional accuracy. Actually, catalyst concentration presents promotion effect on PEG brush thickness growth at the expenses of decreasing dimensional accuracy, while the influence of monomer concentration on PEG brushes thickness exhibits a first increase and then decrease trend. In a global consideration of PEG brushes thickness and micr0pattern dimensional accuracy, optimal catalyst concentration and monomer concentration are proposed as 1.22 mmol/L and 1.22 mol/L, respectively. Furthermore, laser confocal microscopy was applied for the observation of 5-isothiocyanatofluorescein（FITC） labeled bovine serum albumin（BSA） absorption on PEG brushes micropatterned silicon substrates, of which fluorescent and dark contrast images indicate the distinct nonspecific protein adsorption contrast characteristics corresponding to different regions with/without PEG brushes.