2615-07-8Relevant academic research and scientific papers
Synthesis of thermo- and photo-responsive polysiloxanes with tunable phase separation: Via aza-Michael addition
Feng, Kai,Li, Shusheng,Feng, Linglong,Feng, Shengyu
, p. 14498 - 14504 (2017)
Two kinds of thermo- and photo-dual-responsive polysiloxanes (DRPSs) with functional pendent groups, N-isopropyl amides and azobenzene (Azo) or salicylideneaniline (SA), were synthesized through a facile, effective, and catalyst-free aza-Michael addition of poly(aminopropylmethyl-siloxane) with N-isopropyl acrylamide and N-azobenzene acrylamide or N-salicylaldehyde acrylamide. The chemical structrures of DRPSs were systematically characterized using FT-IR, H NMR and UV-Vis spectroscopy. The as-prepared DRPSs with lower Azo or SA contents exhibited lower critical solution temperature (LCST)-type phase transition in water, which is reversible and can be controlled by temperature and UV light. The effects of Azo and SA contents on the responsive properties of DRPSs are examined in detail. The LCST decreased with the increasing Azo or SA content. Once the content of Azo or SA reached up to 5.7% or 8.2%, respectively, DRPSs could not be dissolved in water even in an ice bath. Higher values of the LCST were measured after irradiation of the polymer solutions due to the higher polarity of cis-Azo and keto-SA conformation, induced by irradiation. The differences in cloud points between the irradiated and the non-irradiated DRPS aqueous solutions increased up to 3.4 °C and 9.8 °C when combined with 3.8% Azo and 5.8% SA units, respectively.
Preparation of azobenzene-containing polymer membranes that function in photoregulated molecular recognition
Minoura, Norihiko,Idei, Kazuto,Rachkov, Alexandre,Choi, Young-Woo,Ogiso, Masayo,Matsuda, Kiyomi
, p. 9571 - 9576 (2004)
Selective, stable, molecularly imprinted polymers having intrinsic photoresponsive properties were synthesized for the purpose of photoregulated binding of a predetermined ligand. Highly cross-linked, free-standing polymer membranes were synthesized from
Ultraviolet-responsive self-assembled metallomicelles for photocontrollable catalysis of asymmetric sulfoxidation in water
Gao, Mengqiao,Tan, Rong,Hao, Pengbo,Zhang, Yaoyao,Deng, Jiang,Yin, Donghong
, p. 54570 - 54580 (2017/12/12)
Self-assembled metallomicelles with ultraviolet (UV)-controlled morphologies were constructed from a synthesized azobenzene-containing amphiphilic chiral salen TiIV catalyst. The morphologies of the metallomicelles could be well adjusted by changing the UV irradiation time, and this was confirmed by TEM analyses. The UV-induced change in morphology potentially adjusted the catalyst concentration and/or accessibility in real-time, allowing photocontrollable catalysis of asymmetric sulfoxidation in water. UV-responsive catalytic activities with excellent selectivities were observed over the metallomicelles for a wide range of alkyl aryl sulfides. Moreover, a thermo-responsive NIPAAm block in the catalyst enables it to be easily recovered for steady reuse by thermo-controlled separation. This work constructed a photo-responsive metallomicellar system to carry out metallomicellar catalysis in a controllable way.
