Polystyrene comb polymers built on cellulose or poly(styrene-co-2-hydroxyethylmethacrylate) backbones as substrates for the preparation of structured honeycomb films

Comb polymers were prepared using the RAFT process via a Z-group approach. Trithiocarbonate RAFT agents were covalently bound to a polymer backbone via ester linkages. Two different types of comb polymer backbones were prepared, based on either modified cellulose or statistical poly(styrene-co-2-hydroxyethylmethacrylate) backbones. The subsequent polymerization of styrene from these multi-RAFT-functional backbones displayed some unusual kinetics with the rate of polymerization increasing concomitantly with the trithiocarbonate concentration. The molecular weight of each polystyrene branch increased with conversion, however, deviation from the theoretical molecular weight was detected. The polystyrene comb polymers were utilized in a casting process to prepare highly regular honeycomb structured porous films using breath figures. In general, the regularity was found to increase with increasing number of branches on a backbone and with increasing length of the polystyrene branch.     

Directional Photomanipulation of Breath Figure Arrays

Porous polymeric films are of paramount importance in many areas of modern science and technology. However, processing methods typically based on direct writing, imprint, and lithography techniques have low throughput and are often limited to specific fabricated shapes. Herein, we demonstrate the directional photomanipulation of breath figure arrays (BFAs) formed by an azobenzene‐containing block copolymer to address the aforementioned problems. Under the irradiation of linearly polarized light, the round pores in the BFAs were converted to rectangular, rhombic, and parallelogram‐shaped pores in 30 min, due to the anisotropic mass migration based on the photo‐reconfiguration of the azobenzene units. Through a secondary irradiation after rotating the sample by 90°, the transformed pores were apparently recovered. Therefore, this non‐contacted, directional photomanipulation technique in conjunction with breath figure processing opens a new route to nano/microporous films with finely tuned features.     

李萨如图形法测浅水波波长

本文采用一种非接触光学方法对受外激励的连续变化的水表面波的波长进行实验测量，实验结果与理论曲线吻合较好。     

Equivalence Relations from a Geometrical Point of View

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Breath figures method to control the topography and the functionality of polymeric surfaces in porous films and microspheres

Polymeric films with porous structures and microsphere patterns were prepared by the method of breath figures, mixing poly(methyl methacrylate) (PMMA) and amphiphilic copolymers containing glucose moieties in their structure, glycopolymers. Statistical and block glycopolymers were used in a proportion of 10 wt %. The statistical glycopolymers were synthesized via conventional free radical copolymerization, whereas the block copolymer of methyl methacrylate and 2‐{[(D ‐glucosamin‐2‐Nyl) carbonyl]oxy}ethyl methacrylate, PMMA‐b‐PHEMAGl, was obtained by atom transfer radical polymerization. Glycopolymers were blended with a high molecular weight PMMA matrix and dissolved in a mixture of tetrahydrofuran and a small amount of water. Results showed that, depending on experimental conditions (water content, humidity, and type of copolymer), the observed final film morphology changes significantly. Thus, films with honeycomb pattern structures, spherical particles, or a mixture of both were obtained. In addition, polar glucose moieties were oriented principally either inside of the pores in the case of films and towards the surface in the case of particles. The specific surface bioactivity of these materials was examined using the specific lectin concanavalin A conjugated with fluorescein, Con A‐FITC. The successful binding of the Con A was demonstrated by fluorescence microscopy being more intense at the surface of the pores and of the particles. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012