Title: Towards Future Interfaces With Tuneable Adhesion By Dynamic Excitation
Acronym ERC-Project: SURFACE
Funder: European Research Council – Horizon Europe
Starting date: 01/10/2022
Project duration: 5 years
Grant amount: 1.5 M€
Grant agreement ID: 101039198
CUP: D95F22000430006
DOI: https://doi.org/10.3030/101039198
Principal Investigator: Prof. Antonio Papangelo
e-mail: antonio.papangelo@poliba.it
mobile: +39 3803418061
Short description:
Understanding the adhesive interactions between mechanical components is of fundamental importance in the development of miniaturized mechanical components (MEMS), in pick-and-place manipulation of objects by robotics arms, in the field of human-robot interaction, in bio-engineering for tissue regeneration and wound closure.
Through evolution, nature has developed optimal topographies which are able to adhere to almost any kind of counter-surfaces in both dry and wet conditions, as demonstrated by the astonishing adhesive capabilities of geckos, frogs and octopus. These adhesive performance are often mediated by the presence of multiscale structures, ranging from the millimetre to the nanometre scale, which not only can efficiently adhere, but also can be efficiently detached, resulting in an optimal design for both hanging and walking/running on ceilings and walls. Although in the recent years bio-inspired artificial interfaces have been developed, these are usually “slow”, in a sense that once the interface sticks to the counter-surface it requires some effort to be detached.
More recent research has shown that using high-frequency micrometric vibrations, macroscopic adhesion can be efficiently and rapidly tuned, from very sticky states up to detachment. This behaviour is related to the viscoelastic nature of polymeric materials (silicones, elastomers), which have a frequency-dependent behaviour in terms of both modulus and dissipation.
SURFACE aims at studying the adhesive properties of polymeric micro-structured interfaces subjected to micro-vibrations. Commonly, the design of bio-inspired adhesive surfaces has followed a quasi-static approach, ignoring the effects due to dynamic excitations (vibrations). SURFACE main objective is to design micro-structured surfaces where macroscopic adhesion can be actively adjusted by means of dynamic excitations with proper frequency and amplitude. By exploiting the coupling between geometric and dynamic effects, SURFACE aims to considerably increase the maximum adhesive tension that the surface is able to sustain macroscopically, and to allow active regulation of the adhesive force exchanged upon contact at the timescale of the order of milliseconds. To this end SURFACE plans: (i) to develop efficient numerical algorithms capable of studying soft surfaces subjected to dynamic loading, (ii) to reveal the mechanisms that allow the coupling between the geometry of the interface (topography) and the viscoelastic effects (due to the soft material) in order to determine the interfacial stickiness, (iii) exploit machine learning and artificial intelligence to derive surrogate models representative of the physical behaviour of the interface, (iv) to fabricate polymeric interfaces with multiscale topography and to demonstrate experimentally the adhesive capabilities of the interfaces.
SURFACE has been funded by the European Research Council (ERC), under the action Starting Grant 2021 with 1.5 M€ and it will have a duration of 5 years. Thanks to SURFACE we have established an international research group and a new laboratory, the TriboDynamics Lab, located in the Department of Mechanics Mathematics and Management at Polytechnic University of Bari.
Title: Fighting blindness with two photon polymerization of wet adhesive, biomimetic scaffolds for neurosensory REtina-retinal Pigment epitheliAl Interface Regeneration
Acronym: REPAIR
Funder: Italian Ministry of University and Research – PRIN 2022 PNRR
Starting date: 01/12/2023
Project duration: 2 years
Overall Grant: 239.950 €
Research Unit Grant: 110.175 €
Project ID: P2022TTZZF
CUP: D53D23018570001
Project Coordinator: Prof. Giada Genchi
Coordinator of the PoliBa Research Unit: Prof. Antonio Papangelo
Partners: University of Bari, Bioscience Department
e-mail: antonio.papangelo@poliba.it
mobile: +39 3803418061
Short description:
Retinal integrity alterations due to the detachment of the neurosensory retina (NSR) from the underlying retinal pigment epithelium (RPE) and fluid accumulation in the subretina are common ophthalmology emergencies potentially leading to complete blindness. Timeliness of medical treatments strongly influences visual function recovery, also depending on the extent of retinal detachment, with more favourable prognosis if treatments are provided in a timeframe of a few days since symptom occurrence. In the case of ample detachments resulting into large macular displacement, visual impairment despite highly invasive surgery however becomes irreversible and complete, with strong detrimental socioeconomical implications. This multidisciplinary project therefore aims at developing an innovative scaffold for macular displacement prevention in large retinal detachments, by promoting fast wet adhesion of NSR cells to the underlying cell layers, thus mediating a prompt maintenance and restoration of visual function by minimally invasive surgical approaches. Core enabling technology will be represented by fast prototyping based on two-photon polymerization (2PP) of biomimetic scaffolds with high spatial resolution, in order to recapitulate the NSR-RPE interface architecture (in particular in terms of microstructuring) and to support the recovery of distinctive cellular functions across 2PP interfaces. Scaffold testing in terms of adhesive/mechanical performances will carefully be conducted both in silico (with the aid of computational numeric modelling) and in vitro (by usage of NSR and RPE cell models) in an iterative optimization process of fabrication and functional verification. Scaffold validation will also be corroborated by physiological analyses focused on the electrical properties and calcium signalling of the different cell populations laden on 2PP scaffolds, by histological analyses, and by analyses on the expression of specific markers of intercellular transportation. Versatile biohybrid interfaces with upgradable physicochemical features will eventually be achieved, with potential application to other degenerative conditions (like retinitis pigmentosa or proliferative vitreoretinopathy) requiring rapid adhesion in wet environment and cellular transplantation for successful tissue engineering approaches.
Title: Exploiting Nonlinearities For Friction-Induced Vibrations Mitigation
Acronym: ENOVIM
Starting date: 01/09/2021
Project duration: 2 years
Overall Grant: 38.149 €
CUP: D95F21000910002
Principal Investigator: Prof. Antonio Papangelo
e-mail: antonio.papangelo@poliba.it
Funding body: Regione Puglia (Avviso pubblico per l’attribuzione del contributo a progetti di ricerca scientifica innovativi di elevato standard internazionale (art. 22 della legge regionale 30 novembre 2019, n. 52) approvato con A.D. n. 89 del 10-02-2021 pubblicata nel BURP n. 25 del 18-02-2021.)
Description and results achieved:
The ENOVIM research project, financed by the Puglia Region, has set itself the objective of developing simplified models for the study of contact between components made of soft materials, for example polymers, plastics, silicones. These materials are called viscoelastic and have the peculiarity of effectively dissipating energy when they are subjected to loads that vary over time, making them ideal candidates in the development of systems designed to reduce or eliminate vibrations in mechanical components subject to external loads. For this reason, these materials are increasingly used in engineering with applications ranging from mechanics to aerospace and biomechanics. In particular, the project developed simplified models to simulate the behavior of bodies in contact with particular reference to the energy dissipation due to viscoelasticity and friction. The results obtained from the research project have been published in prestigious international journals [1-4].
The ENOVIM project demonstrated that the viscoelastic contribution is very important in determining the dissipative capacities of components made of polymeric material (typically in aerospace applications: bumpers, stoppers, dampers) and cannot be neglected. Other sources of dissipation to take into account in the design are surface adhesion.
The results obtained are of interest in the mechanical, biomechanical, aeronautical and aerospace fields, therefore they are of interest for the industrial realities present in the territory of Regione Puglia, in particular for the Puglia Aerospace District which brings together more than 57 companies, 8 research centers and universities, also involving the aerospace tourism sector in the near future (Grottaglie spaceport). Furthermore, the ENOVIM research project has strengthened the skills in the field of simulation of mechanical systems of the Polytechnic of Bari and in particular of the Department of Mathematical Mechanics and Management. The numerical tools developed can in fact be exploited for the design of mechanical systems where friction interfaces play a key role (e.g. turbine blades, gears, dampers, bumpers), confirming the quality of the results achieved by the ENOVIM project.
References:
[1] Papangelo, A., & Ciavarella, M. (2022). Viscoelastic dissipation in repeated normal indentation of an Hertzian profile. International journal of solids and structures, 236, 111362.
[2] Ciavarella, M., Papangelo, A., & McMeeking, R. (2022). Transient and steady state viscoelastic crack propagation in a double cantilever beam specimen. International journal of mechanical sciences, 229, 107510.
[3] Papangelo, A., & Ciavarella, M. (2023). Detachment of a rigid flat punch from a viscoelastic material. Tribology letters, 71(2), 48.
[4] Forsbach, F., Heß, M., & Papangelo, A. (2023). A two-scale FEM-BAM approach for fingerpad friction under electroadhesion. Frontiers in mechanical engineering, 8, 1074393.
