Ultrastretchable and Self-Healing Double-Network Hydrogel for 3D Printing and Strain Sensor

Abstract In this study, we evaluated the ease of removal of soot layers from ancient wall paintings by employing double network gels as a controllable cleaning method. The ceiling of the temple of Seti I (Abydos, Egypt) is covered with thick layers of soot; this is especially the case in the sanctuary of Osiris. These layers may have been accumulated during the occupation of the temple by Christians, fleeing the Romans in the first centuries A.D.. Soot particulates are one of the most common deposits to be removed during conservation-restoration activities of (Egyptian) wall paintings. They usually mask the painted reliefs and reduce the permeability of the painted surface. A Polyvinyl alcohol-borax/agarose (PVA-B/AG) double network gel was selected for this task since its properties were expected to be compatible with the cleaning treatment requirements. The gel is characterized by its flexibility, permitting to take the shape of the reliefs, while also having self-healing properties, featuring shape stability and an appropriate capacity to retain liquid. The gel was loaded with several cleaning reagents that proved to be effective for soot removal. Two sets of soot removal tests were conducted with these gel composites. The cleaned surfaces were examined in situ with the naked eye and with a digital microscope in order to select the best gel composite. The gel composite, loaded with a solution of 5% ammonia, 0.3% ammonium carbonate, and 0.3% EDTA yielded the most satisfactory results and allowed to safely remove a crust of thick soot particles from the surface. Thus, during a third phase of the study, it was used successfully to clean a larger area of the ceiling.

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3D Printing of Solvent-Free Supramolecular Polymers

Frontiers in Chemistry ◽

10.3389/fchem.2021.771974 ◽

2021 ◽

Vol 9 ◽

Author(s):

Harald Rupp ◽

Wolfgang H. Binder

Keyword(s):

3D Printing ◽

Dynamic Properties ◽

Polymeric Materials ◽

Fundamental Principle ◽

Supramolecular Polymers ◽

Fused Deposition Modelling ◽

Self Healing ◽

Polymer Science ◽

Fused Deposition ◽

Molecular Ordering

Additive manufacturing has significantly changed polymer science and technology by engineering complex material shapes and compositions. With the advent of dynamic properties in polymeric materials as a fundamental principle to achieve, e.g., self-healing properties, the use of supramolecular chemistry as a tool for molecular ordering has become important. By adjusting molecular nanoscopic (supramolecular) bonds in polymers, rheological properties, immanent for 3D printing, can be adjusted, resulting in shape persistence and improved printing. We here review recent progress in the 3D printing of supramolecular polymers, with a focus on fused deposition modelling (FDM) to overcome some of its limitations still being present up to date and open perspectives for their application.

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Characterization of polyvinyl alcohol-borax/agarose (PVA-B/AG) double network hydrogel utilized for the cleaning of works of art

10.21203/rs.3.rs-48527/v3 ◽

2020 ◽

Author(s):

Ehab Awad Al-Emam ◽

Hilde Soenen ◽

Joost Caen ◽

Koen Janssens

Keyword(s):

Polyvinyl Alcohol ◽

Self Healing ◽

Retention Capacity ◽

Structured Surfaces ◽

Double Network ◽

Liquid Retention ◽

Long Time ◽

Cleaning Procedures ◽

Phase Retention

Abstract Since cleaning of artworks may cause undesirable physicochemical alterations and is a nonreversible procedure, it is mandatory to adopt the proper cleaning procedure. Such a procedure should remove undesired materials whilst preserving the original surface. In this regard, numerous gels have been developed and exploited for the cleaning of various artwork surfaces. Lately, agarose (AG) and polyvinyl alcohol-borax (PVA-B) hydrogels have been widely employed as cleaning tools by conservators. Both hydrogels show some limitations in specific cleaning practices. In this work, we investigated the influence of including increased levels of agarose into PVA-B systems. For this reason, we performed a detailed characterization on the double network (DN) hydrogel including the chemical structure, the liquid phase retention, the rheological behavior, and the self-healing behavior of various PVA-B/AG double network hydrogels. These new hydrogels revealed better properties than PVA-B hydrogels and obviated their limitations. The inclusion of AG into PVA-B systems enhanced the liquid retention capacity, shape-stability, and mechanical strength of the blend. Furthermore, AG minimized the expelling/syneresis issue that occurs when loading PVA-B systems with low polarity solvents or chelating agents. The resultant double network hydrogel exhibits relevant self-healing properties. The PVA-B/AG double network is a new and useful cleaning tool that can be added to the conservators’ tool-kit. It is ideal for cleaning procedures dealing with porous and complex structured surfaces, vertical surfaces and for long time applications.

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On 3D printing of electro-active PVDF-Graphene and Mn-doped ZnO nanoparticle-based composite as a self-healing repair solution for heritage structures

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/09544054211060912 ◽

2021 ◽

pp. 095440542110609

Author(s):

Vinay Kumar ◽

Rupinder Singh ◽

Inderpreet Singh Ahuja

Keyword(s):

3D Printing ◽

Polyvinylidene Fluoride ◽

Nano Particles ◽

Zno Nanoparticle ◽

Self Healing ◽

Fused Deposition ◽

Crack Repair ◽

3D Printed ◽

Doped Zno ◽

Mn Doped

Construction is the part of human activity which is directly linked to urbanization for moving ahead on the path of growth and prosperity. Construction activities in past centuries are now part of our precious heritage. The repair and maintenance of heritage structures are of great importance for present-day researchers. One of the most common damage these century-long constructions faces are in form of surface cracks. In the present study, investigations were performed for a 3D printing-based customized solution for crack repair and maintenance of heritage structures. In this study, polyvinylidene fluoride (PVDF) polymer was reinforced with graphene (Gr) and Mn-doped ZnO nano-particles to prepare a smart composite material for crack repair and restoration. The composite was successfully 3D printed on fused deposition modeling (FDM) based 3D printer after investigating its rheological, thermal, and mechanical properties. The in-house developed composite was tested for smart characteristics to use as a programmable solution for filling cracks. The piezoelectric property and dielectric constant of 3D printed disk-shaped composite (PVDF-Gr-Mn-ZnO) were obtained after DC poling (to be used as stimulus) of the functional prototype. The results of the study suggest that the electro-active nature, volumetric change, and charge storing capacity of the additively manufactured composite may be used practically to acquire the shape of cavity/crack present in the constructed wall and repair the damages that occurred in a heritage site. The photoluminescence (PLS) and atomic force microscopy (AFM) analysis was used to ascertain the properties of the prepared composite. Also, the results obtained from the morphological analysis are reported to support the outcomes of the research.

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A Photoinduced Dual‐Wavelength Approach for 3D Printing and Self‐healing of Thermosetting Materials

Angewandte Chemie ◽

10.1002/ange.202114111 ◽

2021 ◽

Author(s):

Zhiheng Zhang ◽

Nathaniel Corrigan ◽

Cyrille Andre Jean Marie Boyer

Keyword(s):

3D Printing ◽

Dual Wavelength ◽

Self Healing

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