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Blue quantum dot (QD) light emitting diode (QLED) developments are far lagging behind the red and green ones as it becomes difficult to balance charge injection and photo stability than the latter. Here, we introduced a combination of a low band energy shell with better surfactants, which largely meet both abovementioned requirements. Our simulation pinpoints that it is the exposed Se on the QD surface, which causes non-radiative relaxations. By adding tributyl phosphine (TBP), which is a good ligand to Se, we recover photoluminescence quantum yield (PLQY) from less than 8.0% up to above 85.0%. The corresponding external quantum efficiency (EQE) of QLEDs increases from 3.1% to 10.1%. This demonstrates that the low bandgap shell with effective surfactant passivation is a promising strategy to enhance QLED performance.

Over the past decade, 3D bioprinting technology has progressed tremendously in the field of tissue engineering in its ability to fabricate individualized biological constructs with precise geometric designability, which offers us the capability to bridge the divergence between engineered tissue constructs and natural tissues. In this work, we first review the current widely used 3D bioprinting approaches, cells, and materials. Next, the updated applications of this technique in tissue engineering, including bone tissue, cartilage tissue, vascular grafts, skin, neural tissue, heart tissue, liver tissue and lung tissue, are briefly introduced. Then, the prominent advantages of 3D bioprinting in tissue engineering are summarized in detail: rapidly prototyping the customized structure, delivering cell-laden materials with high precision in space, and engineering with a highly controllable microenvironment. The current technical deficiencies of 3D bioprinted constructs in terms of mechanical properties and cell behaviors are afterward illustrated, as well as corresponding improvements. Finally, we conclude with future perspectives about 3D bioprinting in tissue engineering.

The brittleness of ethyl cellulose (EC) film limited its full applications, and the addition of plasticizers is one of the most common methods to reduce its brittleness. However, the mechanical properties are normally dropped with the addition of plasticizers. Herein, cellulose nanocrystal (CNC) was chosen as a reinforcing agent to improve its mechanical properties. CNC was firstly extracted from the tobacco-stem and then modified by epoxidized soybean oil (ESO) via ring-opening grafting to obtain epoxidized soybean oil grafting CNC (ECNC). The grafting effect was evaluated by FTIR and XPS. After that, the films of ECNC/EC nanocomposites were prepared by the solution-casting method, and their mechanical, thermal and optical properties and fracture morphology were investigated. The results showed that at 4 phr loading of ECNC, the tensile strength of the nanocomposite film was up to 43.7 Mpa (about twice as much as that of the EC film plasticized by ESO), and the elongation at break was not influenced. Moreover, a higher thermal decomposition temperature was achieved for the ECNC/EC films. Besides, owing to the good dispersion, ECNC had no significant impact on the transparency, and the films presented high light transmittance in the visible light region.

The ability to effectively manipulate non-equilibrium ‘hot’ carriers could enable novel schemes for highly efficient energy harvesting and interconversion. In the case of semiconductor materials, realization of such hot-carrier schemes is complicated by extremely fast intraband cooling (picosecond to subpicosecond time scales) due to processes such as phonon emission. Here we show that using magnetically doped colloidal semiconductor quantum dots we can achieve extremely fast rates of spin-exchange processes that allow for ‘uphill’ energy transfer with an energy-gain rate that greatly exceeds the intraband cooling rate. This represents a dramatic departure from the usual situation where energy-dissipation via phonon emission outpaces energy gains due to standard Auger-type energy transfer at least by a factor of three. A highly favourable energy gain/loss rate ratio realized in magnetically doped quantum dots can enable effective schemes for capturing kinetic energy of hot, unrelaxed carriers via processes such as spin-exchange-mediated carrier multiplication and upconversion, hot-carrier extraction and electron photoemission. Subpicosecond spin-exchange Auger interactions realized in manganese-doped quantum dots allow for manipulating hot carriers before their intraband cooling.

It is well known that molecular structure has great influence on the porous structure prepared by breath figures. However, the effect of graft architecture on porous structure from graft copolymer is unclear. Here, the cellulose-based graft copolymers with different graft architectures were synthesized and the highly ordered porous films were facilely prepared by breath figure method. The effects of graft architecture with four different structural parameters on porous structure were systematically investigated. It was found that the pore size increased with the increasing graft chain length, main chain length or molecular weight, while the pore size decreased with the increasing graft density under other similar structural parameters. The shorter main chain and the higher graft density resulted in the smaller pore size. Moreover, the shorter main chain was more beneficial for the formation of highly ordered porous structure than the longer main chain. These results will help to understand the effect of graft architecture on porous structure and regulate pore size by adjusting the graft architecture.

Objective: Biopsies are the gold standard for clinical diagnosis. However, a discrepancy between the biopsy sample and target tissue because of misplacement of the biopsy spoon can lead to errors in the diagnosis and subsequent treatment. Thus, correctly determining whether the needle tip is in the tumor is crucial for accurate biopsy results. Methods: A biopsy needle system was designed with a steerable, flexible, and superelastic concentric tube; electrodes to monitor the electrical resistivity; and load cells to monitor the insertion force. The degrees of freedom were analyzed for two working modes: straight-line and deflection. Results: Experimental results showed that the system could perceive the tissue type in online based on the electrical resistivity. In addition, changes in the insertion force indicated transitions between the interfaces of adjacent tissue layers. Conclusion: The two monitoring methods guarantee that the biopsy spoon is at the desired position inside the tumor during an operation. Significance: The proposed biopsy needle system can be integrated into an autonomous robotic biopsy system.

The low efficiency and fast degradation of devices from ink-jet printing process hinders the application of quantum dot light emitting diodes on next generation displays. Passivating the trap states caused by both anion and cation under-coordinated sites on the quantum dot surface with proper ligands for ink-jet printing processing reminds a problem. Here we show, by adapting the idea of dual ionic passivation of quantum dots, ink-jet printed quantum dot light emitting diodes with an external quantum efficiency over 16% and half lifetime of more than 1,721,000 hours were reported for the first time. The liquid phase exchange of ligands fulfills the requirements of ink-jet printing processing for possible mass production. And the performance from ink-jet printed quantum dot light emitting diodes truly opens the gate of quantum dot light emitting diode application for industry., Designing efficient and scalable quantum dot LEDs meeting industrial requirements remains a challenge. Here, the authors, by leveraging the liquid phase exchange of d-MX2 ligands, present printed quantum dot LEDs with external quantum efficiency over 16% and half lifetime of more than 1,721,000 hours.

Shear thickening of suspensions was generally researched as a macro-perspective, the neglect of microstructure and micro-interactions may deviate the truth. Here, four suspensions were prepared by matching SiO2 microspheres, SiO2-g-PMMA microspheres with oligomeric fluids PEG, PPG, respectively, the rheological behavior of them under the controlled temperature was investigated to figure out the influence of grafted chains on shear thickening. For all suspensions, the reversible shear thickening with significant temperature dependency was observed, the critical shear rate ( γ ˙ ) decreases rapidly and reaches to a balance with the decreased temperature. Under the same media viscosity, the γ ˙ of SiO2/PEG suspensions is higher than that of other suspensions at the lower temperature due to the stronger hydrogen bond interaction between the hydroxyl of microsphere and media. Comparing PEG, using low polar PPG as media raises the γ ˙ of SiO2 suspensions and decreases the γ ˙ of SiO2-g-PMMA suspensions by reason of the changed interaction between microsphere and media, which is also affected by temperature. Moreover, the critical shear stress ( τ c ) of SiO2/PEG suspensions is higher than that of other suspensions in all test temperature region, revealing that the grafted chains weaken the jamming effect. Two models were used to predict τ c , the Wagner’s hard-sphere model predicts the SiO2/PEG suspensions well, Kaldasch’s model based on polymer stabilized colloidal system could fit the SiO2-PMMA/PEG suspensions better.

Due to the huge reserves and great commercial potential of No. A group coal seam, the study on its thermal properties and combustion kinetics have attracted much attention. Via thermogravimetric (TG) analysis, the combustion characteristics and kinetics of No. A 3 coal were studied with three types of coal samples, with the grain diameter less than 200 meshes, 200~100 meshes, 100~60meshes, seperately. Under three characteristic temperatures such as T t , T p and T b , the whole combustion process could be roughly divided into 4 stages. Combined with the T max and T i , these five characteristic temperatures increase with elevating heating rates. The Kissinger-Akahira-Sunose (KAS) method and Flynn-Wall-Ozawa (FWO) method as reliable methods were used to verify the results of activation energy ( E a ) determined by of model-fitting methods. As complementary, the Coats-Redfern method was used to calculate the pre-exponential factor ( A ) and the correlation coefficient ( R 2 ). According to the evaluation criteria of E a and R 2 , D1 mechanism was the most probable model to depict the combustion kinetics.

The hand-eye calibration is used to determine the transformation between the end-effector and the camera marker of the robot. But the robot movement in traditional method would be time-consuming, inaccurate and even unavailable in some conditions. The method presented in this article can complete the calibration without any movement and is more suitable in clinical applications.Instead of solving the classic non-linear equation AX = XB, we collected the points on X and Y axes of the tool coordinate system (TCS) with the visual probe and fitted them using the singular value decomposition algorithm (SVD). Then, the transformation was obtained with the data of the tool center point (TCP). A comparison test was conducted to verify the performance of the method.The average translation error and orientation error of the new method are 0.12 ± 0.122 mm and 0.18 ± 0.112° respectively, while they are 0.357 ± 0.347 mm and 0.416 ± 0.234° correspondingly in the traditional method.The high accuracy of the method indicates that it is a good candidate for medical robots, which usually need to work in a sterile environment.

Early prediction is one of the key technologies to the prevention and extinguishment of spontaneous combustion of coal. The aim of this study was to propose a type of scientific and convenient forecasting indicator for initial spontaneous combustion of coal in the gob area. The authors developed the calculation model of carbon monoxide (CO) concentration in the air return corner based on the generation mechanism, sources, and influencing factors of CO. The parameters obtained from both large-scale coal self-heating experiment and in-situ observation of four collieries in Yuanyang lake mine area were used to calculate the extreme value of CO concentrations on various stages of spontaneous combustion. The established indicators were applied to specific coal mine scenarios and combined with the in-situ measurements. It demonstrates that this method has provided the scientific guidance for safer exploitation on coal mines. Furthermore, the main reasons of unstable CO concentrations in the return corne...

GaAs is one of the most important semiconductors. However, colloidal GaAs nanocrystals remain largely unexplored because of the difficulties with their synthesis. Traditional synthetic routes either fail to produce pure GaAs phase or result in materials whose optical properties are very different from the behavior expected for quantum dots of direct-gap semiconductors. In this work, we demonstrate a variety of synthetic routes toward crystalline GaAs NCs. By using a combination of Raman, EXAFS, transient absorption, and EPR spectroscopies, we conclude that unusual optical properties of colloidal GaAs NCs can be related to the presence of Ga vacancies and lattice disorder. These defects do not manifest themselves in TEM images and powder X-ray diffraction patterns but are responsible for the lack of absorption features even in apparently crystalline GaAs nanoparticles. We introduce a novel molten salt based annealing approach to alleviate these structural defects and show the emergence of size-dependent excitonic transitions in colloidal GaAs quantum dots.

Application of 3D printing in the individualized fabrication of biological organ receives more and more attentions. The adopted movement trajectories of nozzle in 3D printing are all based on depositing materials vertically layer by layer. We noticed that the biological organ has always anisotropic property and its natural growing procedure implies a so-called stereotactic fabrication method which can be implemented utilizing robotic techniques. In this research, we proposed and simulated a robot-assisted stereotactic printing method. Kinematics analysis of the robotic manipulator was analyzed. Trajectory planning method for stereotactic operation was designed. Motion simulation analysis of the planned trajectory utilizing manipulator was conducted which validated effectiveness of the proposed printing system from aspects of motion accuracy, flexibility, and potential collisions. The results indicated flexibility of the proposed robot-assisted stereotactic printing technology.

Impurity doping has been widely used to endow semiconductor nanocrystals with novel optical, electronic, and magnetic functionalities. Here, we introduce a new family of doped NCs offering unique insights into the chemical mechanism of doping, as well as into the fundamental interactions between the dopant and the semiconductor host. Specifically, by elucidating the role of relative bond strengths within the precursor and the host lattice, we develop an effective approach for incorporating manganese (Mn) ions into nanocrystals of lead-halide perovskites (CsPbX3, where X = Cl, Br, or I). In a key enabling step not possible in, for example, II–VI nanocrystals, we use gentle chemical means to finely and reversibly tune the nanocrystal band gap over a wide range of energies (1.8–3.1 eV) via postsynthetic anion exchange. We observe a dramatic effect of halide identity on relative intensities of intrinsic band-edge and Mn emission bands, which we ascribe to the influence of the energy difference between the cor...

A new polyhedral oligomeric silsesquioxane (POSS) hybrid hydrogels were desinged and fabricated by introducing cationic octa-ammonium (Oa)-POSS) into chemically cross-linked cationic PDMAEMA hydrogels via in situ radical freezing polymerization. The prepared gels (shorten as OP-PD gels) show considerably improved properties through the effective incorporation and dispersion of Oa-POSS particles in gels. Comparing to the Oa-POSS-free gels, the hybrid gels own better mechanical properties with higher tensile and compressive strength. Meantime, except the decreased swelling ratio in acid condition, the OP-PD gels still keep excellent swelling ability with obvious pH and temperature double responsiveness, which is affected by the content of Oa-POSS slightly. All OP-PD gels exhibit an ultrarapid deswelling rate due to the interconnected micropores structure caused by freezing and the formation of microhydrophobic region around POSS particles. Moreover, the application potential of OP-PD gels in drug release was exploited by using flutamide as target drug, the result showed that the increased Oa-POSS could improve the drug loading ability, and OP-PD gels showed well controlled-release effect in simulated human stomachic condition. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2345-2355, 2016.

The test method and principle that isothermal difference leading the elevated temperature experiment and the large coal spontaneous ignition experiment are different, data acquisition methods are also different, the content and calculation basis of coal spontaneous combustion characterization parameters and solution are slightly different. In order to realize the comparative analysis of isothermal difference leading experiment and large coal spontaneous combustion experiment, it selects samples of Zhaoxian Coal Mine to conduct large coal spontaneous combustion experiment (defined as ZXDY) and isothermal difference leading experiment (defined as ZXYM), and to make an analysis of the characterization parameters of coal spontaneous combustion, obtaining the characteristics and applicability of the two experimental methods of coal spontaneous combustion characterization parameters.

Traditional polymer filtration membranes are easily polluted in operation. An interpenetrating polymer network (IPN) gel was designed as a self-supported filter membrane. This IPN gel was structured by a Ca2+ crosslinked alginate network and a covalently crosslinked poly(acrylamide) network. Polyethylene glycol-polyhedral oligomeric silsesquioxane (PEG-POSS) was hybridised into the gel to optimise performance. Our research demonstrated that the uniform dispersion of PEG-POSS in the matrix improved membrane performance comprehensively due to its nanoscale and amphipathicity. The membranes showed well mechanical properties and sewage treatment capacity. Under the operation pressure 2 bar, the water flux of membranes could keep 11.7 L m−2 h−1 in long-term use. When dealing with the high concentration (500 mg L−1) of Methylene blue and Congo red solution, the rejection of dye could reach 93% and 95% respectively. In anti-fouling experiments with 8000 mg L−1 protein emulsion as the fouling source, the membranes keep over 80% initial flux after 10 times of water-emulsion cycle.

The condensation of water vapor on cold surfaces is termed as breath figures. It is fascinating that the highly ordered breath figure arrays can be formed by simple evaporation of a volatile polymer solution. It has been speculated that the ordered breath figure arrays originate from ordered water droplet arrays induced by the evaporation of volatile solvents. However, it is unknown what the real formation process of ordered water droplet arrays on volatile surfaces of pure solvents is. Herein, we report the real-time observation of the growth process of water droplets on the volatile surface of the pure solvent of carbon disulfide by using an optical microscope. We observed the highly ordered water droplet arrays on the volatile surface. We found six distinct stages during the evaporation process. The growth mechanism of water droplets obeys individual growth before coalescing. In addition, a few defects of large water droplets, vacancies and irregular boundaries were observed. The rapid movement of water droplets indicated the strong convective current in the solvent, promoting the rearrangement of water droplets to form more ordered arrays. The highly ordered water droplet arrays only need a moist environment, which is very convenient for ordered structures. Our findings not only provide direct evidence for ordered water droplet arrays but also quantitatively clarify their dynamic process, which helps to understand the mechanism of ordered breath figure arrays.

Poly(butylene adipate-co-terephthalate) (PBAT) has good biodegradability and mechanical properties, but its high cost limits its full applications. The incorporation of thermoplastic starch (TPS) into PBAT can significantly lower the cost, but the mechanical properties of the obtained PBAT/TPS composites are dramatically reduced. Herein, the PBAT/TPS composites with excellent mechanical properties were prepared by simple melt-blending extrusion in combination with the reinforcing and compatibilizing strategy. The results showed that the tensile strength of the reinforced and double-compatibilized composite significantly increased by 50%, and its elongation at break increased by 18%. The increased mechanical properties indicated improved compatibility, which was confirmed by SEM. The presence of the additives had no significant effect on the thermal stability and the crystalline structures of the composites. Moreover, the composite melt was a typical pseudoplastic fluid, showing easy processibility. The PBAT-based composites with excellent performance and reduced cost by simple melt-extrusion processing will show promising applications.

Grasping by robotic devices for manipulation and transposition is one of the fundamental and ubiquitous tasks in various domains, including industrial, food and medical fields. Grasping safety is crucial for manipulated object, especially for brittle item or biological target. Thus, contact force, which is a vital factor for grasping safety, has been studied for decades. From the angle of view of system structure design, various kinds of soft gloves are proposed for reducing grasping contact force. However, existing soft gloves are designed to drive fingers from the back of the hand, without considering contact force between finger and manipulated object. The forces between five fingers and object are not equal and often big differences exist between forces on fingers. Aforementioned emerging soft graspers with multiple fingers lack study on balancing contact force of all fingers. Thus, in this paper, a soft hand pad is designed to balance contact force between all fingers. A balancing force control algorithm is developed, which can fulfill balancing force control through adjusting air-pressure of fingers during its grasping object. Experiments verify the proposed soft hand pad design, and the balancing force control algorithm.

Soft tissue cutting is a fundamental operation in clinical treatments. Autonomous soft tissue cutting using scalpel, one of soft tissue cutting methods, is an emerging field. However, soft tissue displacement during cutting by robotic system is a bottleneck. In this paper, a robotic system is proposed with sucker that can fix soft tissue before and during cutting. The system consists of scalpel fixation and three degrees of freedom (DoF) motion structure and surrounding suckers at the bottom. Cutting curve is abstracted from the cut soft tissue imaged by X-ray. Then the curve is fitted using 10-order B-spline function. The experimental results provide a pilot study towards high precision soft tissue cutting robot.

Effective magnetic fields as high as 30 T can arise in magnetically doped nanocrystals due to spin fluctuations alone, and can now be observed using ultrafast optical spectroscopy. Strong quantum confinement in semiconductors can compress the wavefunctions of band electrons and holes to nanometre-scale volumes, significantly enhancing interactions between themselves and individual dopants. In magnetically doped semiconductors, where paramagnetic dopants (such as Mn2+, Co2+ and so on) couple to band carriers via strong sp–d spin exchange1,2, giant magneto-optical effects can therefore be realized in confined geometries using few3,4,5,6,7 or even single8,9 impurity spins. Importantly, however, thermodynamic spin fluctuations become increasingly relevant in this few-spin limit10. In nanoscale volumes, the statistical fluctuations of N spins are expected to generate giant effective magnetic fields Beff, which should dramatically impact carrier spin dynamics, even in the absence of any applied field. Here we directly and unambiguously reveal the large Beff that exist in Mn2+-doped CdSe colloidal nanocrystals using ultrafast optical spectroscopy. At zero applied magnetic field, extremely rapid (300–600 GHz) spin precession of photoinjected electrons is observed, indicating Beff ∼ 15 −30 T for electrons. Precession frequencies exceed 2 THz in applied magnetic fields. These signals arise from electron precession about the random fields due to statistically incomplete cancellation of the embedded Mn2+ moments, thereby revealing the initial coherent dynamics of magnetic polaron formation, and highlighting the importance of magnetization fluctuations on carrier spin dynamics in nanomaterials.

The use of semiconductor nanocrystal quantum dots (QDs) in optoelectronic devices typically requires postsynthetic chemical surface treatments to enhance electronic coupling between QDs and allow for efficient charge transport in QD films. Despite their importance in solar cells and infrared (IR) light-emitting diodes and photodetectors, advances in these chemical treatments for lead chalcogenide (PbE; E = S, Se, Te) QDs have lagged behind those of, for instance, II-VI semiconductor QDs. Here, we introduce a method for fast and effective ligand exchange for PbE QDs in solution, resulting in QDs completely passivated by a wide range of small anionic ligands. Due to electrostatic stabilization, these QDs are readily dispersible in polar solvents, in which they form highly concentrated solutions that remain stable for months. QDs of all three Pb chalcogenides retain their photoluminescence, allowing for a detailed study of the effect of the surface ionic double layer on electronic passivation of QD surfaces, which we find can be explained using the hard/soft acid-base theory. Importantly, we prepare highly conductive films of PbS, PbSe, and PbTe QDs by directly casting from solution without further chemical treatment, as determined by field-effect transistor measurements. This method allows for precise control over the surface chemistry, and therefore the transport properties of deposited films. It also permits single-step deposition of films of unprecedented thickness via continuous processing techniques, as we demonstrate by preparing a dense, smooth, 5.3-μm-thick PbSe QD film via doctor-blading. As such, it offers important advantages over laborious layer-by-layer methods for solar cells and photodetectors, while opening the door to new possibilities in ionizing-radiation detectors.

In semiconductors, quantum confinement can greatly enhance the interaction between band carriers (electrons and holes) and dopant atoms. One manifestation of this enhancement is the increased stability of exciton magnetic polarons in magnetically-doped nanostructures. In the limit of very strong 0D confinement that is realized in colloidal semiconductor nanocrystals, a single exciton can exert an effective exchange field $B_{\rm{ex}}$ on the embedded magnetic dopants that exceeds several tesla. Here we use the very sensitive method of resonant photoluminescence (PL) to directly measure the presence and properties of exciton magnetic polarons in colloidal Cd$_{1-x}$Mn$_x$Se nanocrystals. Despite small Mn$^{2+}$ concentrations ($x$=0.4-1.6\%), large polaron binding energies up to $\sim$26~meV are observed at low temperatures via the substantial Stokes shift between the pump laser and the resonant PL maximum, indicating nearly complete alignment of all Mn$^{2+}$ spins by $B_{\rm{ex}}$. Temperature and magnetic field-dependent studies reveal that $B_{\rm{ex}} \approx$ 10~T in these nanocrystals, in good agreement with theoretical estimates. Further, the emission linewidths provide direct insight into the statistical fluctuations of the Mn$^{2+}$ spins. These resonant PL studies provide detailed insight into collective magnetic phenomena, especially in lightly-doped nanocrystals where conventional techniques such as nonresonant PL or time-resolved PL provide ambiguous results., Comment: 12 pages, 8 figures, Nano Letters articles ASAP (2017)

Organic-inorganic lead-halide perovskites have been the subject of recent intense interest due to their unusually strong photovoltaic performance. A new addition to the perovskite family is all-inorganic Cs-Pb-halide perovskite nanocrystals, or quantum dots, fabricated via a moderate-temperature colloidal synthesis. While being only recently introduced to the research community, these nanomaterials have already shown promise for a range of applications from color-converting phosphors and light-emitting diodes to lasers, and even room-temperature single-photon sources. Knowledge of the optical properties of perovskite quantum dots still remains vastly incomplete. Here we apply various time-resolved spectroscopic techniques to conduct a comprehensive study of spectral and dynamical characteristics of single- and multiexciton states in CsPbX3 nanocrystals with X being either Br, I, or their mixture. Specifically, we measure exciton radiative lifetimes, absorption cross-sections, and derive the degeneracies of the band-edge electron and hole states. We also characterize the rates of intraband cooling and nonradiative Auger recombination and evaluate the strength of exciton-exciton coupling. The overall conclusion of this work is that spectroscopic properties of Cs-Pb-halide quantum dots are largely similar to those of quantum dots of more traditional semiconductors such as CdSe and PbSe. At the same time, we observe some distinctions including, for example, an appreciable effect of the halide identity on radiative lifetimes, considerably shorter biexciton Auger lifetimes, and apparent deviation of their size dependence from the "universal volume scaling" previously observed for many traditional nanocrystal systems. The high efficiency of Auger decay in perovskite quantum dots is detrimental to their prospective applications in light-emitting devices and lasers. This points toward the need for the development of approaches for effective suppression of Auger recombination in these nanomaterials, using perhaps insights gained from previous studies of II-VI nanocrystals.

The microporous hydrogels (Pn-Cm gels) composed of poly(dimethylaminoethyl methacrylate) and carboxymethylchitosan were synthesized in situ radical polymerization by using nano γ-Fe2O3 particles as pore-agent. The microporous structure formed through eliminating the Fe2O3 particles was designed to achieve a faster response rate and better drug loading effect. Comparing to the neat gels, Pn-Cm gels exhibit deteriorative mechanical properties with the increased pores, while the gels still keep the elastic network structure which could bear some degree of tensile and compression deformation. Meantime, Pn-Cm gels show similar temperature and pH double responsiveness with same isoelectric point shrink as that of neat gels, the swelling ability decreases slightly, and the deswelling rate increases with the increase of pores. Moreover, the 5-fluorouracil was used as a target drug to explore the potential of this gel applied as drug-release system. For Pn-Cm gels, the more pores and carboxymethyl chitosan inside the gels are beneficial to the drug loading, all gels show a burst release of drug, being followed by a slow and sustained release with different rate. Comprehensively, the Pn-Cm gels exhibit a better sustained release effect in the simulated stomach condition (pH = 2.1), the related release mechanism could be interpreted by the superposition of Fickian diffusion. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45326.