Research progress and application prospect of functional adhesive materials in the field of oil and gas drilling and production

By summarizing the composition,classification,and performance characterization of functional adhesive materials,the adhesion mechanisms of functional adhesive materials,such as adsorption/surface reaction,diffusion,mechanical interlocking,and electrostatic adsorption,are expounded.The research status of these materials in oil and gas drilling and production engineering field such as lost circulation prevention/control,wellbore stabilization,hydraulic fracturing,and profile control and water plugging,and their application challenges and prospects in oil and gas drilling and production are introduced comprehensively.According to the applications of functional adhesive materials in the field of oil and gas drilling and production at this stage,the key research directions of functional adhesive materials in the area of oil and gas drilling and production are proposed:(1)blending and modifying thermoplastic resins or designing curable thermoplastic resins to improve the bonding performance and pressure bearing capacity of adhesive lost circulation materials;(2)introducing low-cost adhesive groups and positive charge structures into polymers to reduce the cost of wellbore strengthening agents and improve their adhesion performance on the wellbore;(3)introducing thermally reversible covalent bond into thermosetting resin to prevent backflow of proppant and improve the compressive strength of adhesive proppant;(4)introducing thermally reversible covalent bonds into thermoplastic polymers to improve the temperature resistance,salt-resistance and water shutoff performance of adhesive water shutoff agents.

New Adhesive Material for Construction Joint of Tunnel Lining

The new adhesive material for the construction joints of tunnel lining(named as SZC) was studied based on the structural characteristics of interfaces and the characteristic of bonding construction, and the performance indexes were verified by tests. The experimental results show that the adhesive capability of interface is improved effectively by using SZC material, the properties, such as anti-freezing, erosion-resistance and anti-shrinkage are improved greatly as well as durability.

Fully umbilical cord-derived adhesive materials enable to recruit and segregate immune cells for the reversal of acute liver failure

Inflammatory cytokine storms can trigger disease exacerbation and even death and have reached a consensus in the clinical treatment of acute organ failure.However,the existing strategies remain a great challenge to efficiently suppress inflammatory cytokine storms for promoting organ repair and regeneration.Herein,fully human umbilical cord(UC)-derived adhesive materials(UCAM)that integrate decellularized extracellular matrix(ECM)nanofiber hydrogel and homologous mesenchymal stem cells(MSCs)are demonstrated to greatly suppress inflammatory cytokine storms,demonstrating high efficacy in treating acute liver failure(ALF)in rats with 90%hepatectomy.The UC-derived adhesive materials have the capacity to secrete a significant quantity of cytokines by MSCs to recruit activated immune cells to migrate into their ECM nanofiber networks,segregating them away from the infection area and thereby greatly suppressing the inflammatory cytokine storms.As expected,the UC-derived adhesive materials can significantly promote hepatocyte proliferation to achieve functional recovery and regeneration of the liver,significantly improving the survival rate in rats.Our fully human UC-derived adhesive materials provide a new avenue in suppressing inflammatory cytokine storms for promoting organ regeneration that would be really utility in clinical organ transplantation-related treatment.

Wet-adhesive materials of oral and maxillofacial region:From design to application

Oral and maxillofacial diseases are a group of high-incidence disorders that affect people’s life quality to a great extent,while the wet and highly movable environment of the related regions brings challenges to traditional therapies.Faced with the obstacles of insufficient adhesive strength and ensuing short drug retention time,conventional oral therapeutic agents often have difficulty in achieving their desired efficacy.Oral and maxillofacial wet-adhesive materials have the advantages of excellent wet environment retention,internal stability,plasticity,and clinical potential,thus have become a significant research direction in the field of oral related disorders healing.In the past decade,the development of oral adhesive materials with good wet adhesion has accelerated based on the chemical molecular interaction,physical interlocking,and biological adhesion mechanisms,including biomimetic-inspired materials,naturally derived polymer–based materials and adhesive electrospun fiber films.These fancy wet-adhesive materials can be used for oral mucosal drug delivery,oral vaccination,wound healing,and bone defects treatments.Despite their numerous novel applications,wet-adhesive materials in stomatology still face unresolved challenges from material and biological aspects.Here,advances in designs of oral and maxillofacial wetadhesive materials are reviewed in terms of design backgrounds,attachment mechanisms,and common classifications.Recent demonstrations of wet-adhesive materials for oral and maxillofacial region medical applications from drug delivery to multifunctional tissue treatments are presented.To conclude,current challenges and prospects on potential applications of oral and maxillofacial wet-adhesive materials are also briefly discussed.

Supramolecular adhesive materials from small‐molecule self‐assembly

Developing high‐performance adhesive materials not only aims at industrial and social requirements but also bears the fundamental importance of understanding the chemical factors of biological adhesion to develop biomimetic adhesive materials.Owing to the wide development of supramolecular chemistry,numerous supramolecular tools are exploited and proved to be reliable in the replacement of traditional covalent materials by reversible noncovalent or dynamic covalent materials.Taking advantage of these readyto‐use supramolecular toolboxes,supramolecular adhesive materials are rising and promising toward“smart”adhesives,that is,enabling responsiveness,reversibility,and recyclability.Compared with polymeric adhesive materials,low‐molecular‐weight adhesives feature chemically precise structure,easier engineering by molecular design,and hence higher reproducibility.However,it remains highly challenging to make high‐performance adhesive materials by low‐molecular‐weight feedstocks.This review will focus on the recent advancement in the construction of supramolecular adhesive materials by smallmolecule self‐assembly.The design guidelines and consideration on the molecular scale will be discussed and summarized on how to enhance the strength of adhesives.Meanwhile,owing to the dynamic nature of supramolecular self‐assembly,several“smart”functions of such materials will be presented,such as stimuli–responsiveness and adaptiveness.Finally,current challenges and future perspectives of this emerging field will be proposed.

Supramolecular Adhesive Materials from Natural Acids and Sugars with Tough and Organic Solvent-Resistant Adhesion

Natural adhesives have been widely replaced by industrial adhesives made from petroleum-based products.Compared with that of traditional natural adhesives,modern industrial adhesives show improved adhesion performance.However,the drawbacks of modern adhesives,including toxicity and nonbiodegradability,drive the need for new and high-performance adhesive materials from renewable and biocompatible natural feedstock.In this study,a new family of acid-sugar adhesive materials exhibiting excellent and long-term adhesion effects was developed inspired by the concept of deep eutectic solvents(DESs).The supramolecular polymerization between natural sugars and acids gave rise to both strong cohesion and adhesion properties.Moreover,high resistance to organic solvents is an advantage of acid-sugar supramolecular adhesive materials.This study not only dramatically expands the applications of DESs but also sheds light on the development of supramolecular adhesive materials as promising alternatives to polymeric adhesives.

The dynamic stress intensity factor analysis of adhesively bonded material interface crack with damage under shear loading

This paper studies the dynamic stress intensity factor （DSIF） at the interface in an adhesive joint under shear loading. Material damage is considered. By introducing the dislocation density function and using the integral transform, the problem is reduced to algebraic equations and can be solved with the collocation dots method in the Laplace domain. Time response of DSIF is calculated with the inverse Laplace integral transform. The results show that the mode Ⅱ DSIF increases with the shear relaxation parameter, shear module and Poisson ratio, while decreases with the swell relaxation parameter. Damage shielding only occurs at the initial stage of crack propagation. The singular index of crack tip is -0.5 and independent on the material parameters, damage conditions of materials, and time. The oscillatory index is controlled by viscoelastic material parameters.

Dynamic fracture analysis of adhesive bonded material under normal loading

Dynamic fracture behavior of a Griffith crack along the interface of an adhesive bonded material under normal loading is studied. The singular integral equations are obtained by employing integral transformation and introducing dislocation density functions. By adopting Gauss-Jacobi integration formula, the problem is reduced to the solution of algebraic equations, and by collocation dots method. their solutions can be obtained Based on the parametric discussions presented in the paper, the following conclusions can be drawn： （1） Mode I dynamic stress intensity factor （DSIF） increases with increasing initial crack length and decreasing visco-elastic layer thickness, revealing distinct size effect; （2） The influence of the visco-elastic adhesive relaxation time on the DSIF should not be ignored.

Modification of Interfacial Performance of Fiber Bragg Grating Embedded in the Composite Materials

The interfacial performance of the Fiber Bragg grating（FGB） embedded in the composite was studied and the influence of interface modification on the final profile of the spectra of the FBG sensor was examined. A type of polyamine（Pentaethylenehexamine, PEHA） was proposed to modify the coating of PI on FBG, and the interfacial performance was evaluated by a pull-out test. Sharp improvements of the interfacial shear strength（77%） were obtained by 40 min treatment of PEHA. Compared with untreated specimen, FGB spectra of treated specimen in the tensile tests show improved linearity within the test regime, which proves that the enhanced interface is beneficial for the sensing performance.

Effect of spatial configuration on adhesion of 1,2-disubstituted cyclohexane derivatives

Spatial configuration has a significant effect on chemical self-assembly.However,the importance of spatial configuration in supramolecular adhesive materials has been frequently ignored.In this study,the effects of the spatial configuration on cohesion and adhesion were investigated.Owing to the diversities of the chemical structures and assembly patterns,1,2-disubstituted cyclohexane derivatives were used in this combined experimental and theoretical investigation.The self-sorting assembly of enantiopure isomers improved cohesion but had a negative effect on adhesion.In contrast,racemic mixtures displayed stronger adhesion effects.Moreover,it was proven that the cis-configuration was more favorable for supramolecular adhesion than the trans-counterpart.In addition,the influence of the spatial configuration of 1,2-disubstituted cyclohexane derivatives could be effectively mitigated by hydrogen bond donors or acceptors.The addition of natural acids yielded three-dimensional polymeric networks,in which the spatial configuration was not the decisive factor for supramolecular adhesion.

A Four-legged Wall-climbing Robot with Spines and Miniature Setae Array Inspired by Longicorn and Gecko

In industrial applications,climbing robots are widely used for climbing and detection of rough or smooth pipe surfaces.Inspired by the special claws of longicorn is that can crawl on rough surfaces and the array of tiny bristles of geckos that can crawl on smooth surfaces,a new type of wall-climbing robot for rough or smooth surfaces is proposed in this paper.The bionic palms of the robot are suggested with special bionic hooks inspired by the longicorn and bionic adhesive materials inspired by the gecko with a good performance on adhering on the surfaces.The special bionic hooks are manufactured by the 3D printing method and the bionic adhesive materials are made by the polymer print lithography technology.These two different bionic adhere accessory are used on the robot’s palm to achieve climbing on the different surfaces.This foldable climbing robot can not only bend its own body to accommodate the cylindrical contact surfaces of different diameters,but also crawl on vertical rough and smooth surfaces using their bionic palms.

Design,Modeling and Experimentation of a Biomimetic Wall-climbing Robot for Multiple Surfaces

Wall-climbing robots can work on steep terrain and obtain environment information in three dimensions for human in real time,which can improve operation efficiency.However,traditional single-mode robots cannot ensure the stable attachment on complex wall surfaces.Inspired by the structure characteristics of flies and clingfishes,three bionic structures including the flexible spine wheel,the adhesive material and the adsorption system are proposed.Aiming at task requirements on multiple walls and based on the above three bionic structures,a wall-climbing robot with the composed mode of“grabbing+adhesion+adsorption”is presented v/a the law of mechanism configuration synthesis.Using static analysis,the safe attachment conditions for the robot on smooth and rough walls are that the adsorption force is 30 N or more.Based on Newton's Euler and Lagrange formulas,the dynamic equations of the robot on vertical walls are established to deduce that the maximum theoretical torque of the driving motor is 1.43 N·m at a uniform speed.Finally,the prototype of the wall-climbing robot is manufactured and tested on the vertical lime wall,coarse sandpaper wall and acrylic ceiling wall.Meanwhile,experiment results imply that the average maximum moving speed and the corresponding load are 7.19 cm·s-1 and 0.8 kg on the vertical lime wall,7.78 cm·s-1 and 0.6 kg on the coarse sandpaper wall,and 5.93 cm·s-1 and 0.2 kg on the acrylic ceiling wall respectively.These findings could provide practical reference for the robot’s application on walls.