As robotic technology advances towards autonomy and intelligence, tactile sensing systems have become a key technology for overcoming the bottleneck of environmental interaction. Unlike visual perception, which captures macroscopic information, tactile sensing provides precise mechanical feedback for robotic manipulation by real-time analysis of microscopic physical parameters such as contact force, material properties, and surface morphology. This is particularly important in application scenarios that require high precision in force control, such as minimally invasive surgery and precision assembly, where the sensitivity, multimodal perception capabilities, and environmental adaptability of tactile sensors directly determine the operational performance of the robotic system. However, traditional tactile sensors are limited by rigid structures, limited sensitivity, and a single perception modality, making it difficult to meet the demands of complex interactions. In recent years, breakthroughs in flexible electronic materials, biomimetic microstructure design, and multimodal sensing integration technologies have provided innovative opportunities for tactile sensing systems. This review provides a detailed overview of the key technological advancements in tactile sensors and their applications in robotic surfaces, analyzes the major challenges currently faced, and looks ahead to future development directions, particularly the potential in flexible materials and intelligent algorithms. Received: 25 March 2025 | Revised: 26 May 2025 | Accepted: 28 May 2025 Conflicts of Interest PingAn Hu is the Editor-in-Chief for Smart Wearable Technology and was not involved in the editorial review or the decision to publish this article. The authors declare that they have no conflicts of interest to this work. Data Availability Statement Data sharing is not applicable to this article as no new data were created or analyzed in this study. Author Contribution Statement Huiwen Ren: Conceptualization, Methodology, Software, Validation, Formal analysis, Investigation, Resources, Data curation, Writing – original draft, Writing – review & editing, Visualization. Wangyang Li: Methodology, Software, Validation, Formal analysis, Investigation, Resources, Data curation, Writing – original draft, Writing – review & editing, Visualization. Yanan Ding: Resources, Data curation, Writing – original draft, Writing – review & editing, Visualization. Yuming Feng: Writing – original draft. Hexin Li: Resources, Data curation, Writing – original draft, Writing – review & editing, Visualization. Jianyang Li: Writing – original draft, Writing – review & editing. Jia Zhang: Writing – original draft, Writing – review & editing, Supervision. Haiying Xiao: Writing – original draft, Writing – review & editing. Jialu Li: Writing – original draft, Writing – review & editing. Shuai Wang: Writing – original draft. Cong Huang: Writing – original draft, Writing – review & editing, Supervision. Li Jiang: Writing – original draft, Writing – review & editing, Supervision. PingAn Hu: Conceptualization, Methodology, Writing – original draft, Writing – review & editing, Supervision, Project administration, Funding acquisition.

Silane coupling agent (SCA), a kind of organic solvent, was introduced to improve the performance of coral coarse aggregates and enhance the interfacial adhesion between the inorganic coral aggregate and the cement paste of coral concrete. The crushing indicator and water absorption of the coral aggregates over various dipping times were measured, and the slump, interface microhardness, and compressive strength of coral concrete tested. The microscopic appearances of the coral concrete before and after modification were analyzed based on SEM images. The experimental results indicate that SCA can effectively reduce the crushing indicator and water absorption of coral coarse aggregates, and the modification performance becomes better over time. SCA facilitates the generation of chemical forces between the coral aggregates and cement mortars, improves adhesion between the aggregates and mortars, augments the microhardness of the interface, and increases the compressive strength. According to the microscopic appearance of the treated and untreated coral aggregate interfaces, the aggregates and the mortars are in closer combination after modification.

In this paper, an ultrahigh-strength marine concrete containing coral aggregates is developed. Concrete fabricated from marine sources is considered an effective and economical alternative for marine engineering and the construction of remote islands. To protect sea coral ecosystems, the coral aggregates used for construction are only efflorescent coral debris. To achieve the expected mechanical performance from the studied concrete, an optimal mixture design is conducted to determine the optimal proportions of components, in order to optimize the compressive strength. The mechanical properties and the autogenous shrinkage, as well as the heat flow of early hydration reactions, are measured. The hydration products fill up the pores of coral aggregates, endowing our concrete with flowability and self-compacting ability. The phases in the marine concrete are identified via X-ray diffraction analysis. The 28-day compressive and flexural strength of the developed marine concrete achieve 116.76 MPa and 18.24 MPa, respectively. On account of the lower cement content and the internal curing provided by coral aggregates, the volume change resulting from autogenous shrinkage is only 63.11% of that of ordinary reactive powder concrete.

Coral concrete has low cost and convenient materials, making it an excellent raw material for processing. However, its lower strength limits the application of coral concrete. Surface modification is expected to increase the properties of porous coral concrete. In this study, single and compound modification treatments were applied to the surface of a coral aggregate to improve its properties for promoting the mechanical performance of coral concrete. The results showed that the micro-aggregate effect and pozzolanic activity of granulated blast furnace slag (GBFS) and the permeability and polycondensation of sodium silicate (SS) could be mutually promoted. The GBFS and SS could effectively fill the pores of the coral aggregate, enhancing the properties of the aggregate, such as density and load-bearing capacity, and reducing the water absorption and crushing index by more than 50%. GBFS and SS could intensify and accelerate the hydration of cement, and generate a large number of hard hydration products at the interfacial transition zone (ITZ), which could strengthen the bonding between the aggregate and mortar, improving the strength of the ITZ. The compressive strength of the coral concrete was significantly increased.

In the present work, the properties of graphene-nanoplates/aluminum (GNPs/Al) composites with a heterogeneous matrix design were investigated. The advantage of the heterogeneous matrix was investigated by the finite element method. Then, 0.6 wt.% (GNPs/6061Al)/2024Al (heterogeneous matrix) and 0.6 wt.% GNPs/6061Al composites were prepared by ball milling, pressure infiltration technology, and hot extrusion. The aggregation of GNPs was eliminated and the interlayer slide of GNPs was observed. Mechanical property test results show that the mechanical properties of the heterogeneous matrix composite are better than that of a homogeneous matrix composite, including strength, elastic modulus, and plasticity. It is assumed that the heterogeneous matrix design enhances the non-uniform stress field during the deformation treatment. This improves the dispersion of GNPs, grain refinement, and produces the few-layer graphene (FLG), thus enhancing the strengthening effect of GNPs. Meanwhile, heterogeneous matrix design is thought to introduce more hardening mechanisms to increase the plasticity of materials and improve the intrinsic trade-off of strength and toughness.

InSe/β-Ga ₂ O ₃ heterojunction detects 230 nm deep UV under zero bias.