Xiang Meng,Jiajun Ma,Kang Xie,Liang Hong,Junxi Zhang,Zhijia Hu
We have demonstrated a low threshold and tunable flexible random laser (RL) in dye-doped poly ethylene glycol diacrylate (PEG-DA) hydrogel, which was prepared by crosslinking polymerization using PEG-DA monomer and photoinitiator. The random lasering is attributed to the light scattering from the porous structure of hydrogels, and the wavelength of random lasing can be tuned by ~3.2 nm in the temperature range from 30 °C to 70 °C. Under the continuous increasing and decreasing temperature cycle, the random lasing tunable phenomenon can still be observed, which proves that this flexible material can be used as a new temperature sensor . In addition, we also explored the application of flexible laser in phototherapy. Considering the good elasticity and transparency of hydrogels, this thermo-responsive property will be of great significance to the biomedical applications of flexible material.
In this contribution, shape memory polymers (SMPs) of chemically-crosslinked zwitterionic polyurethanes (CZPUs) were fabricated by crosslinking of the N,N-bis(2-hydroxyethyl) isonicotinamide (BINA)/hexamethylene diisocyanate (HDI) polyurethanes system by using pentaerythritol (PER), followed by zwitterionization with 1, 3-propanesultone (PS). As the zwitterionic units increased, it was found that the glass transition of hard phase in CZPUs remains constant while that of soft phase shifted at lower temperature, and a broad glass transition was obtained. The broad glass transition enables CZPUs to display triple, quadruple, and quintuple shape memory behaviours. Meanwhile, due to the chemically-crosslinked structure, the CZPUs exhibited an excellent shape fixation and recovery. Furthermore, the CZPU also exhibited good moisture-induced shape memory effect (SME) with a fast and high shape recovery observed below 70% RH and at 37 °C. The excellent thermally-induced multi-shape memory effect and moisture-induced shape memory effect enable CZPUs to be applied as smart materials for many applications among them the biomedical fields .
A water-processable blue fluorescent silver nanoparticle@graphene–polymer composite (Ag@G–pNIPAM) consisting of graphene coated with a thermally responsive poly-(N-isopropylacrylamide) (pNIPAM) shell is prepared. The pNIPAM shell swells or collapses as a function of temperature, serving as a means to trap silver nanoparticles in solution and get them sufficiently close to the graphene core to provide fluorescence enhancement based on the local surface plasmon resonance (LSPR) effect. The unique thermoresponsive properties and high enhancement ratio of the material should find application in solution fluorescence enhancers and a variety of biomedical applications, such as cellular uptake, sensing and imaging.
危险品化学品经营许可证（带存储）