Developing tough and conductive materials is crucial for the fields of wearable devices. However, soft materials like polyurethane (PU) are usually non-conductive, whereas conductive materials like carbon nanotubes (CNTs) are usually brittle. Besides, their composites usually face poor interfacial interactions, leading to a decline in performance in practical use. Here, we develop a stretchable PU/CNTs composite foam for use as a strain sensor. A cationic chain extender is incorporated to afford PU cationic groups and to regulate its mechanical properties, whose tensile strength is up to 12.30 MPa and breaking strain exceeds 1000%, and which shows considerable adhesion capability. Furthermore, porous PU foam is prepared via a salt-templating method and carboxylic CNTs with negative groups are loaded to afford the foam conductivity. The obtained foam shows high sensitivity to small strain (GF = 5.2) and exhibits outstanding long-term cycling performance, which is then used for diverse motion detection. The strategy illustrated here should provide new insights into the design of highly efficient PU-based sensors. Developing tough and conductive materials is very crucial for the fields of wearable devices. We develop a stretchable polyurethane/carbon nanotubes composite, which shows excellent mechanical performance and high sensitivity to small strain.

An artificial skin that simulates not only the mechanical performance but also the conductive behavior of natural skin is developed based on a zwitterionic polyurethane ionogel, which could be used as wearable sensors.

Human activities have led to elevated levels of selenium (Se) in the environment, which poses a threat to eco-systems and human health. Stenotrophomonas sp. EGS12 (EGS12) has been identified as a potential candidate for the bioremediation of repair selenium-contaminated environment because of its ability to efficiently reduce Se (IV) to form selenium nanospheres (SeNPs). To better understand the molecular mechanism of EGS12 in response to Se(IV) stress, a combination of transmission electron microscopy (TEM), genome sequencing techniques, metabolomics and transcriptomics were employed. The results indicated that under 2 mM Se(IV) stress, 132 differential metabolites (DEMs) were identified, and they were significantly enriched in metabolic pathways such as glutathione metabolism and amino acid metabolism. Under the Se(IV) stress of 2 mM, 662 differential genes (DEGs) involved in heavy metal transport, stress response, and toxin synthesis were identified in EGS12. These findings suggest that EGS12 may respond to Se(IV) stress by engaging various mechanisms such as forming biofilms, repairing damaged cell walls/cell membranes, reducing Se(IV) translocation into cells, increasing Se (IV) efflux, multiplying Se(IV) reduction pathways and expelling SeNPs through cell lysis and vesicular transport. The study also discusses the potential of EGS12 to repair Se contamination alone and co-repair with Se-tolerant plants (e.g. Cardamine enshiensis). Our work provides new insights into microbial tolerance to heavy metals and offers valuable information for bio-remediation techniques on Se(IV) contamination.

The schematic diagram of the charge transfer path of an LDH/CN nanocomposite for photocatalytic degradation of TC and photocatalytic hydrogen evolution.

Development of smart switchable surfaces to solve the inevitable bacteria attachment and colonization has attracted much attention; however, it proves very challenging to achieve on-demand regeneration for noncontaminated surfaces. We herein report a smart, host-guest interaction-mediated photo/temperature dual-controlled antibacterial surface, topologically combining stimuli-responsive polymers with nanobactericide. From the point of view of long-chain polymer design, the peculiar hydration layer generated by hydrophilic poly(2-hydroxyethyl methacrylate) (polyHEMA) segments severs the route of initial bacterial attachment and subsequent proliferation, while the synergistic effect on chain conformation transformation poly(N-isopropylacrylamide) (polyNIPAM) and guest complex dissociation azobenzene/cyclodextrin (Azo/CD) complex greatly promotes the on-demand bacterial release in response to the switch of temperature and UV light. Therefore, the resulting surface exhibits triple successive antimicrobial functions simultaneously: (i) resists ∼84.9% of initial bacterial attachment, (ii) kills ∼93.2% of inevitable bacteria attack, and (iii) releases over 94.9% of killed bacteria even after three cycles. The detailed results not only present a potential and promising strategy to develop renewable antibacterial surfaces with successive antimicrobial functions but also contribute a new antimicrobial platform to biomedical or surgical applications.

Hydrophobic micro-porous membrane such as polyvinylidene fluoride (PVDF) with excellent thermal-/chemical-stability and low surface energy has received extensive attention in industrial water treatment and sustainable energy conversion. However, undesirable contaminants caused by inevitable proteins or microorganisms adhesion may lead to a rapid loss of separation efficiency, which significantly deteriorate their porous structures and eventually limit their practical performance. Herein, we present a scalable approach for fabricating comb-like copolymer modified PVDF membranes (PVDF-PN@AgNPs) that prevent bacteria from proliferating on the surface and temperature-controlled release of adhered contaminants. Comb-like structured copolymers were imparted to a polydopamine (PDA)-treated PVDF membrane by Michael addition reaction, which enabled a covalent binding of comb-like structured copolymers to the membrane. Such unique structural design of grafted copolymer, containing hydrophilic side chain and temperature-responsive chain backbone, stably prevents bacteria adhesion and provides reversible surface wettability. Therefore, the resultant membranes were evaluated to prevent bacterial adhesion, high touch-killing efficiency and temperature-controlled contaminants release (~99% of protein and ~75% of bacteria). Moreover, with the collapse and stretch of grafted copolymer chain backbone, the synthetic membrane further reversibly adjusted inner micro-porous structure and surface wettability, which eventually helped to achieve variable water fluid transport efficiency. This study not only provides a feasible structural design for stably coping with the challenging of antifouling and subsequent contamination adhesion of PVDF membrane, but also potentially answers the significant gap between lab research advances and practical application, particularly in the industrial membrane field.

Numerous efforts to fabricate antimicrobial surfaces by simple yet universal protocols with high efficiency have attracted considerable interest but proved to be particularly challenging. Herein, we designed and fabricated a series of antimicrobial polymeric coatings with different functions from single to multiple mechanisms by selectively utilizing diethylene glycol diglycidyl ether (PEGDGE), polylysine, and poly[glycidylmethacrylate-co-3-(dimethyl(4-vinylbenzyl)ammonium)propyl sulfonate] (poly(GMA-co-DVBAPS)) via straightforward mussel-inspired codeposition techniques. Bactericidal polylysine endowed the modified surfaces with a high ability (∼90%) to kill attached bacteria, while PEGDGE components with unique surface hydration prevented bacterial adhesion, avoiding the initial biofilm formation. Moreover, excellent salt-responsive poly(GMA-co-DVBAPS) enabled reactant polymeric coatings to change chain conformations from shrinkable to stretchable state and subsequently release >90% attached bacteria when treated with NaCl solution, even after repeated cycles. Therefore, the obtained polymeric coatings, polydopamine/poly(GMA-co-DVBAPS) (PDA/PDV), polydopamine/polylysine/poly(GMA-co-DVBAPS) (PDA/l-PDV), and polydopamine/polylysine/poly(GMA-co-DVBAPS)/diethylene glycol diglycidyl ether (PDA/l-PDV-PEGDGE), controllably realized functions from single and dual to multiple antimicrobial mechanisms, as evidenced by long-term antifouling activity to bacteria, high bactericidal efficiency, and salt-responsive bacterial regeneration performance with several bacterial killing-release cycles. This study not only contributes to mussel-inspired chemistry for polymeric coatings with controllable functions but also provides a series of reliable and highly efficient antimicrobial surfaces for potential biomedical applications.

Bacteria in the external environment inevitably invade the wound and subsequently colonize the wound surface during surgery and biomedical operations, which slows down the process of wound healing and tissue repair; this poses a significant threat to human health. Therefore, the development of an intelligent antibacterial surface has become the focus of research in the field of antimicrobial strategies, which has important social and economic significance. Here, we present a simple approach of producing an ionic interaction-driven anionic activation substratum which is then functionalized with cationic molecules through coulombic interactional immobilization. The switchable multifunctional antibacterial surface can decrease bacterial attachment and inactivate the attached microorganisms, thus overcoming the conventional challenge for antibacterial surfaces. Briefly, poly (3-sulfopropyl methacrylate potassium salt) (PSPMA) brushes were constructed by surface-initiated atom transfer radical polymerization on silicon or cotton fabric substrates, and a positive-charged component, namely lysozyme (LYZ), hexadecyl trimethyl ammonium bromide (CTAB) or chitosan (CS), was loaded on negative-charged sulfonate groups through electrostatic interactions. The resultant brush-grafted surfaces exhibited more than ∼95.5% bactericidal efficacy and ∼92.8% release rate after the introduction of an adequate amount of contra-ions (1.0 M; Na+ & Cl-) against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, thus achieving a regenerated surface through the cyclic process of "assembly-dissociation". Smart cotton fabric (Fabric-PSPMA/LYZ and Fabric-PSPMA/CS) surfaces were constructed, which were found to promote wound epidermal tissue regeneration with a higher efficiency after 7-day in vivo studies. This ionic interaction-driven method used in the present work is simple and can reversibly renew antibacterial surfaces, which will help in the wider utilization of switchable antibacterial materials with a more ecologic and economic significance. STATEMENT OF SIGNIFICANCE: Smart antibacterial surfaces with renewable characteristics have attracted considerable interests over the past few years. Here, we used ionic interaction-driven force to manipulate dynamic conformational changes in PSPMA surface brushes, accompanied by highly switchable bacteria killing and bacteria releasing behaviors. Different cationic molecules were also designed for assembly/dissociation on the PSPMA-modified surfaces, and the essential parameters, including chemical structures, molecular weight, and cationic charge density, were investigated. With the refined structural combinations and the balance of bacteria killing/bacteria releasing behaviors, smart cotton fabrics (e.g., Fabric-PSPMA/lysozyme and Fabric-PSPMA/chitosan) were designed that could promote wound healing and tissue repair. These results contribute to the fundamental understanding of a switchable cationic-anionic pair design and the corresponding practical, renewable, highly antibacterial fabric.

It is still challenging to fabricate polymer foams with bimodal structure via a simple technique in the both in-dustrial and academic fields. In this work, by mixing polydimethylsiloxane (PDMS) into thermoplastic poly-urethane (TPU) and utilizing the difference of foaming dynamics between TPU and PDMS, the target foams with bimodal structures were successfully prepared through a one-step foaming process. It was shown that under the optimal conditions (i.e. PDMS content of 15 wt%, foaming temperature of 100 degrees C and foaming pressure of 13.8 MPa), the resultant foam possessed distinct bimodal structures with large cells of similar to 12 mu m and small cells of similar to 3 mu m. Such bimodal structures also help the forms to have the excellent compress strength and modulus of 506 kPa and 1618 kPa, which are much higher than the foam with uniform structure. In addition, bimodal structure foam has similar to 3 dB higher sound insulation than uniform structure foam.

Continuously growing interest in the controlled and tunable transport or separation of target molecules has attracted more attention recently. However, traditional "on-off" stimuli-responsive membranes are limited to nongradient feedback, which manifests as filtration efficiency that cannot be increased or decreased gradually along with the different stimuli conditions; indeed, only the transformation of on/off state is visible. Herein, we design and fabricate a series of robust salt-responsive SiO2@cellulose membranes (SRMs) by simply combining salt-responsive poly[3-(dimethyl(4-vinylbenzyl)ammonium)propyl sulfonate] (polyDVBAPS)-modified SiO2 nanoparticles and cellulose membranes under negative-pressure filtering. The antipolyelectrolyte effect induces stretch/shrinkage of polyDVBAPS chains inside the channels and facilities the directional aperture size and surface wettability variation, greatly enhancing the variability of interfacial transport and separation efficiency. Due to the linear salt-responsive feedback mechanism, the optimal SRMs achieve highly efficient target macromolecule separation (>75%) and rapid oil/saline separation (>97%) with a continuous gradient and adjustable permeability, instead of simply an "on-off" switch. The salt-responsive factors (SiO2-polyDVBAPS) could be reversibly separated or self-assembled to membrane substrates; thus, SRMs achieved unprecedented repeatability and reusability even after long-term cyclic testing, which exceeds those of currently reported membranes. Such SRMs possess simultaneously a superfast responsive time, a controllable gradient permeability, a high gating ratio, and an excellent reusability, making our strategy a potentially exciting approach for efficient osmotic transportation and target molecule separation in a more controllable manner.

Abstract In the study of marine geology, the sampling technology and preservation are very important links. Marine geology is developed on the basis of marine sediment sampling technology. ORM (Object-Relation Mapping) technology is an effective method to solve the “impedance mismatch” between object model and relation model. The research on object-relation mapping technology has become a research hotspot in the field of software architecture. The development of object-relational database has enhanced the ability of database to support complex data types, making the integrated storage of spatial data, topological relations and attribute data a reality. This paper proposes a class hierarchy based on the technical framework of object-relational mapping, and explains all kinds of classes. The application of this framework can simplify the mapping mechanism on the premise of meeting the requirements of marine geological sampling, thus providing users with an object-oriented way to intuitively access the database.

The enhanced adsorption of methylene blue in aqueous solution is triggered by the phase transition of the thermo-responsive polymer poly(di(ethylene glycol) methyl ether methacrylate-co-poly(ethyle...

Instead of previously reported graphene oxide (GO), industrial graphene (reduced graphene oxide (IrGO)) was annealed with a nitrogen precursor. The obtained nitrogen-doped graphene (N-IrGO) was then employed as a novel catalyst for peroxymonosulfate (PMS) activation to degrade benzophenone-1 (BP-1) for the first time. The results show that N-IrGO exhibits excellent catalytic performance over conventional GO and its nitrogen-doped sample and was even better than the metal catalysts Co3O4 and Fe3O4. The enhanced catalytic performance might be attributed to graphitic-like nitrogen. Moreover, the effects of various factors were studied, including catalyst load, PMS concentration and reaction temperature. Possible degradation pathways of BP-1 in the N-IrGO/PMS system were proposed based on detected intermediates and the frontier electron density calculation. Radical quenching experiments and electron paramagnetic resonance (EPR) tests indicated that nonradical oxidation (singlet oxygen (1O2)) plays a dominant role in the BP-1 degradation, in contrast to the previously proposed radical process. Finally, mineralization and stability experiments confirmed that N-IrGO may be an alternative catalyst for environmental remediation. This study contributes to designing novel graphene materials with N doping and gives new insight into nonradical oxidation on benzophenone-type UV filters degradation.

A new method was proposed for fabricating the polymer foams with bimodal structure. Briefly, nanoparticles and polymer powders were dry-mixed by ball-milling and then hot-pressed into the composites in which nanoparticles were selectively distributed at the interfaces between polymer multi-facets. Upon batch foaming using scCO(2) as blowing agent, bimodal structure was generated due to the selective distribution and heterogeneous nucleation effect of the nanoparticles. Using this method, several bimodal composite foams based on different nanoparticles, i.e. graphene, carbon nanotubes, and silica nanoparticles and different polymers, i.e. thermoplastic polyurethane (TPU) and polystyrene (PS) were successfully fabricated. Specifically, TPU/graphene system was systemically studied. The results showed that the foam morphologies could be easily tuned by changing nanoparticle content, particle size of polymer powder, hot-pressing temperature and pressure, as well as foaming conditions (e. g. foaming temperature and pressure), indicating the great simplicity and tune-ability of this method.

Development of novel materials with dual antibacterial and antifouling functions is important for many bio-applications. In this work, we design and synthesize a series of mixed polymer brushes grafted from silica surface as a new type of antibiofouling and antimicrobial coating, which combine poly(N-hydroxyethyl acrylamide) (polyHEAA) synthesized by atom transfer radical polymerization (SI-ATRP) and cationic poly(trimethylamino) ethyl methacrylate chloride, polyMETAC) synthesized by photoiniferter-mediated polymerization (SI-PIMP). The surface composition, charge and morphology of the resultant mixed polymer brushes are carefully characterized and optimized by tuning ATRP and PIMP initiator ratios. The mixed polymer brushes possess strong bacterial killing ability from polyMETAC chains and high antifouling property from polyHEAA chains. At the optimal conditions, the mixed polyHEAA/polyMETAC brushes exhibit excellent anti-bacterial adhesion property by retaining ultralow cell adhesion of (similar to)3.0 x 105 cells/cm2 and high contact killing efficiency by killing more than 90% attached bacteria of Escherichia coil and Staphylococcus. Long-term antibacterial performance indicated the cell adhesion was retained at ultralow level of 5 x 105 cells/cm2 even after 72 h exposure to bacteria solution. The results indicate that surface grafting with polyHEAA and polyMETAC can be potentially useful for long-term biomedical and biomaterial applications.

Polyzwitterionic brushes with strong antipolyelectrolyte effects have shown great potential as versatile platforms for the development of switchable friction/lubrication and bacterial absorption/desorption surfaces. However, the surface property switches of these brushes are usually triggered by high salt concentrations (>0.53 M), thereby greatly limiting their applications in biological fields where the salt concentration for mammals is ?0.15 M. To solve this problem, an electric field was used to assist the salt-responsive process of the polyzwitterionic brushes to achieve bacterial release at low concentrations of the salt solution. Briefly, poly(3-(dimethyl (4-vinylbenzyl) ammonium) propyl sulfonate) (polyDVBAPS) brushes grafted on ITO surfaces were prepared by surface initiated atom transfer radical polymerization. The bacterial release of this surface was conducted under an electric field, where anions were migrated and enriched around the brush-grafted ITO surface as anode. The local high concentration ion led to the conformation change of the brush and release of the attached bacteria. The effect of salt type, salt concentration, electric field strength, and conducting time on the bacterial release properties were investigated. The results indicated that under an electrical field of 3 V/mm, polyDVBAPS showed release capacities of ?93% for E. coli and ?81% for S. aureus in 0.12 M NaCl electrolyte solution. Furthermore, by the introduction of a bactericidal agent, i.e., Triclosan (TCS), an antibacterial surface with dual functions of killing and release was fabricated. This surface could kill ?90% and release 95% of attached E. coli in a 0.12 M NaCl solution by the application of a 3 V/mm electric field. This work demonstrated the feasibility of triggering a salt-responsive behavior of polyzwitterionic at low salt concentration by assistance of electric field, which would greatly extend the applications of polyzwitterionic, in particular in biological applications.

Polyzwitterionic brushes with strong anti-polyelectrolyte effect have shown great potential as smart surfaces for tunable lubrication, protein absorption/desorption, and bacteria killing and release. However, due to the brush structure in which polymer chain is tethered on the substrate by one end, this surface is easily destroyed from the detachment of the brush, greatly limiting its real-world applications. To solve this problem, herein, cross-linked structure was introduced in poly(3-(dimethyl (4-vinylbenzyl) ammonium) propyl sulfonate) (polyDVBAPS) brushes to offer the long-term stability. The cross-link structure was fabricated by adding a cross-linker during the surface initiated atom transfer radical polymerization, and the effect of such structure on the surface morphology, salt-responsive behavior, and long-term stability were investigated. The results indicated that the crosslink structure with tunable cross-link density could be readily prepared by this method. The responsive behaviors, such as switch between friction and lubrication, bacteria release in response to salt solution, were well-retained by the cross-linked polyDVBAPS brush. More importantly, high long-term stability was endowed by the cross-link structure, from which the cross-linked brush not only showed long-time lubrication and high load resistance during friction measurements, but also exhibited a high retention ratio (more than 90%) of bacteria release capability even after 30 water/salt solution switch cycles, in contrast, the non-cross-linked brush showed a low retention ratio of (similar to)50% after the similar treatment. These results indicated that cross-linked structure could be an efficient method to enhance the stability of responsive polymer brushes and greatly strengthen the practicability of such brushes in real-world applications.

"Janus-featured" hydrogels with different structure and function for each layer can be particularly important in diverse application. However, very few studies have been conducted on multifunctional Janus-featured hydrogel, and significant challenge for simple, rapid, and efficient fabrication of such hydrogels remains. Herein, Janus-featured poly(N-hydroxyethyl acrylamide) (polyHEAA) hydrogel loaded with modified silica nanoparticle was fabricated by the supergravity method. Silica nanoparticles grafted with poly(3-(dimethyl(4-vinylbenzyl) ammonio) propyl sulfonate) (polyDVBAPS) were first prepared and then introduced into progel of polyHEAA hydrogel. During the formation of the hydrogel, a supergravity resulting from centrifugation was applied, from which silica nanoparticles moved to one side of the hydrogel, forming Janus-featured hydrogels, i.e., a pristine polyHEAA layer and a composite layer. These two layers showed different properties, where the prinstine polyHEAA layer showed excellent antifouling property by resisting the bacteria adsorption (<10(6) cells/cm(2)) for up to 5 days, and the nanoparticle-loaded hydrogel layer showed excellent bacteria-releasing properties by releasing >94% adherent bacteria upon a simple treatment with 2.0 M NaCl solution for 10 min. Based on its superb biocompatibility and low biotoxicity, we expect that our interesting strategy may provide a new assumption for the fabrication of "Janus featured" hydrogel and hopefully offer reference significance for the design of hydrogel-based wound dressing in the near future.

Stimuli-responsive surfaces with switchable bacterial killing and release are new promising candidates for the development of new antibacterial materials. Although such surfaces have been extensively studied and many advances have been achieved, a number of challenges are remained, including the optimization of structure, moderate stimuli, and so forth. In this paper, we developed a new "killing and release" antibacterial surface by combining poly[2-(tert-butylamino) ethyl methacrylate] (polyTA) and poly(3-(dimethyl (4-vinylbenzyl) ammonio) propyl sulfonate) (polyDVBAPS) via mixed brushes system. The bactericidal activity of polyTA and salt-responsive property of polyDVBAPS could be well integrated in this way. Accordingly, the surface showed high bactericidal activity by killing more than 94% attached bacteria of E. coli and S. aureus and excellent release capability by detaching most attached bacteria in response to salt solution. Both bacterial killing effectiveness and release rate were well retained at a high level of more than 90% after four severe killing and release cycles, indicating the high reliability of surface regeneration. This excellent antibacterial potency made the surface capable to be used in many biological applications, particularly in reusable devices.

Until now more than 14 subway lines are in operation and some new lines are being built in the coastal city Shanghai. The longitudinal settlement of shield tunnel has significant effect on the safety of the subway operation. In this paper, the deformation of the shield tunnel and the surrounding soil were analyzed by the establishment of a three-dimensional model. The vertical displacements of four paths (Path 1 is on the ground; Path 2 is at the top of the tunnel; Path 3 is in the middle of the tunnel; Path 4 is at the bottom of the tunnel) are affected by the nature of the soil. The horizontal displacement is smaller than the vertical displacement and horizontal displacement of the clay is larger than that of the sand. The distribution of the pore pressure changes with soil properties around the tunnel. The pore pressure of the sand layer is larger than that of the clay layer at the same depth of underlying soil.