296248-02-7Relevant academic research and scientific papers
Self-assembly and photoinduced optical anisotropy in dendronized supramolecular azopolymers
Del Barrio, Jesus,Blasco, Eva,Toprakcioglu, Chris,Koutsioubas, Alexandros,Scherman, Oren A.,Oriol, Luis,Sanchez-Somolinos, Carlos
, p. 897 - 906 (2014)
Herein we report the preparation and characterization of dendronized supramolecular polymers composed of a carboxy-Terminated azodendron, dAZO, and two different vinylpyridine-containing polymers: poly(4-vinylpyridine) (P4VP) and polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) block copolymer. P4VP can selectively complex dAZO through hydrogen-bonding interactions, thus resulting in liquid crystalline materials. Additionally, this strategy is also applicable to the preparation of dendronized supramolecular block copolymers (BCs). Lamellar, cylindrical, and spherical morphologies are observed for the BC complexes depending on the dAZO to vinylpyridine repeating unit ratio. Photoinduced orientation of the azobenzene moieties is obtained in films of the H-bonded materials - both P4VP and PS-b-P4VP based complexes - by using 488 nm linearly polarized light and characterized through birefringence and dichroism measurements. High and stable values of birefringence are obtained for polymers with azobenzene content as low as 2.7 wt %, thus demonstrating the benefits of preorganization in photoactive dendritic moieties in side-chain H-bonded materials.
Photoresponsive polymers and block copolymers by molecular recognition based on multiple hydrogen bonds
Concell?n, Alberto,Blasco, Eva,Pi?ol, Milagros,Oriol, Luis,Díez, Isabel,Berges, Cristina,Sánchez-Somolinos, Carlos,Alcalá, Rafael
, p. 3173 - 3184 (2016/02/18)
A new methacrylate containing a 2,6-diacylaminopyridine (DAP) group was synthesized and polymerized via RAFT polymerization to prepare homopolymethacrylates (PDAP) and diblock copolymers combined with a poly(methyl methacrylate) block (PMMA-b-PDAP). These
Synthesis, characterization, and photoresponsive behavior of a series of azobenzene-containing side-chain poly(ether sulfone)s with various lengths of flexible spacers
Zhang, Yuxuan,Pei, Songhao,Wang, Yongpeng,Cui, Zengduo,Li, Na,Zhu, Ye,Zhang, Haibo,Jiang, Zhenhua
, p. 1117 - 1123 (2013/10/08)
A series of azobenzene-containing side-chain poly(ether sulfone)s (azo-PES) with various spacer lengths (2, 6 or 12 methylene units) were successfully synthesized via a nucleophilic substitution grafting reaction between poly(ether sulfone)s with hydroxylphenyl side groups and azobenzene monomers. Their chemical structures and properties were characterized by means of IR, UV-vis and 1H NMR. These azo-polymers show good thermal stability with glass transition temperatures and 5% weight-loss temperatures above 119 C and 347 C, respectively. The results of photoisomerization experiments indicated that azo-PES polymer with longer spacers correspond to higher photoisomerization rates. Upon irradiation with a 532 nm neodymium doped yttrium aluminum garnet (Nd:YAG) laser beam, they presented remnant values of birefringence larger than 82% of the saturation value of birefringence, indicating the good stability of the photoinduced orientation. No fatigue phenomena have been observed after several cycles of inscription-erasure-inscription sequences.
