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A novel, cost‐effective strategy for sensing performance enhancement of cantilever‐shaped, mass‐sensitive sensors is presented. The developed strategy relies on the introduction of macroporosity in the recognition unit. The developed sensors are successfully applied in air humidity monitoring as well as in chemical sensing. As mass‐sensitive transducers, polymer microelectromechanical systems (MEMS) in the form of poly(vinylidene fluoride‐trifluoroethylene) [P(VDF‐TrFE)] cantilever resonators are specifically developed. These resonators are modified with a hierarchically structured macroporous poly(2,3′‐bithiophene) film, acting as a sensing layer. The design of the recognition layer takes advantage of the synergistic combination of inverse opal structuring, surface imprinting, and semi‐covalent imprinting of proteins. The resulting cantilever resonators are first successfully tested for air humidity monitoring in the whole relative humidity range (ca.10 – 90%). When the recognition layer is composed of human serum albumin‐imprinted polymer (HSA‐MIP) with a hierarchical structure, it can also be used as a selective chemosensor in a concentration range from 10 pM to 20 µM. The obtained results demonstrate that the macroporosity of the receptor film significantly enhances the sensor performance. [ABSTRACT FROM AUTHOR]

The one‐step printing of fully functional electronic devices is one of the main goals of additive manufacturing. In general, this approach is increasingly growing, being one of the key developments additive manufacturing processes based on ultraviolet curing. The main reasons for this increasing interest in UV curing based technologies are its advantages, such as fast curing at room temperature, space and energy efficiency, high‐resolution patterns, and solvent‐free formulations. Despite the important developments, some challenges remain with respect to improving UV curing process and, in particular, to obtain smart UV curable materials, many times based on the inclusion of specific nanoparticles in a UV curable polymer matrix. Thus, this paper reviews the recent developments in UV curable smart materials for printing technologies focusing on both materials and processes. The curing mechanisms and the main materials used in UV photocurable resins are reviewed as well as the main smart and multifunctional materials obtained based on them. Finally, a summary of the main achievement and the future needs are indicated. This review represents therefore a landmark for the development of a new generation of UV curable smart and multifunctional materials and solutions. The basic principles and the fundamental components of UV curable polymer‐based smart materials for printing technologies are reported. The main 2D and 3D printing technologies for UV curable polymers are presented, together with the most important smart UV curable materials and applications based on polymer matrix and active nanofillers. Finally, the main future challenges are indicated. [ABSTRACT FROM AUTHOR]

Mechanical resonators have been used for various applications including timing references, filters, accelerometers, and inertial sensors. Mostly, silicon‐based materials have been thought to be ideal considering robustness and stability and thus used to fabricate micro and nanoscale mechanical resonators. When enhanced sensitivity becomes more important than long‐term stability, materials repertoires other than silicon might be better suited. Herein, a novel manufacturing approach is proposed, which rapidly fabricates microelectromechanical system resonators with hydrogel by single UV exposure via dynamic mask and dry‐state "plugging out" sacrificial process where hydrogel structures are defined by spatially modulated UV light. For practical demonstrations, rectangular cantilevers and closed circular membranes are employed for humidity and pressure sensing applications, respectively. The cost‐effective fabrication route suggested herein not only enables rapid prototyping of suspended hydrogel structures outside a cleanroom, but also offers spatially tunable elastic modulus. Most remarkably, sensitivity enhancement resulting from high swelling rate and/or low elastic modulus exceeds stability deterioration, one of the major concerns for polymeric materials. Such exclusive beneficial features, yet demonstrated with any microfabrication materials and methods or their combinations, open a new avenue for photocurable polymeric materials to be used for specific applications as well as fundamental investigations. Various suspended hydrogel microstructures are fabricated by employing dynamic mask lithography and dry‐state sacrificial process. After thorough characterization, hydrogel resonators are successfully employed for humidity and pressure sensing via either optical transduction with laser and photodetector or electrical transduction with integrated metal piezoresistors deposited through hydrogel shadow masks that are also made by dynamic mask lithography. [ABSTRACT FROM AUTHOR]