scholarly journals Tuning the Properties of Nanogel Surfaces by Grafting Charged Alkylamine Brushes

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1514 ◽  
Author(s):  
Zbyšek Posel ◽  
Paola Posocco

Nanogels are chemically crosslinked polymeric nanoparticles endowed with high encapsulation ability, tunable size, ease of preparation, and responsiveness to external stimuli. The presence of specific functional groups on their surfaces provides an opportunity to tune their surface properties and direct their behavior. In this work, we used mesoscale modeling to describe conformational and mechanical properties of nanogel surfaces formed by crosslinked polyethylene glycol and polyethyleneimine, and grafted by charged alkylamine brushes of different lengths. Simulations show that both number of chains per area and chain length can be used to tune the properties of the coating. Properly selecting these two parameters allows switching from a hydrated, responsive coating to a dried, highly charged layer. The results also suggest that the scaling behavior of alkylamine brushes, e.g., the transition from a mushroom to semi-dilute brush, is only weakly coupled with the shielding ability of the coating and much more with its compressibility.

Crystals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 62
Author(s):  
Xu Xu ◽  
Zeping Zhang ◽  
Wenjuan Yao

Graphene and graphene oxide (GO) usually have grain boundaries (GBs) in the process of synthesis and preparation. Here, we “attach” GBs into GO, a new molecular configuration i.e., polycrystalline graphene oxide (PGO) is proposed. This paper aims to provide an insight into the stability and mechanical properties of PGO by using the molecular dynamics method. For this purpose, the “bottom-up” multi-structure-spatial design performance of PGO and the physical mechanism associated with the spatial structure in mixed dimensions (combination of sp2 and sp3) were studied. Also, the effect of defect coupling (GBs and functional groups) on the mechanical properties was revealed. Our results demonstrate that the existence of the GBs reduces the mechanical properties of PGO and show an “induction” role during the tensile fracture process. The presence of functional groups converts in-plane sp2 carbon atoms into out-of-plane sp3 hybrid carbons, causing uneven stress distribution. Moreover, the mechanical characteristics of PGO are very sensitive to the oxygen content of functional groups, which decrease with the increase of oxygen content. The weakening degree of epoxy groups is slightly greater than that of hydroxyl groups. Finally, we find that the mechanical properties of PGO will fall to the lowest values due to the defect coupling amplification mechanism when the functional groups are distributed at GBs.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 624
Author(s):  
Cintya Dharmayanti ◽  
Todd A. Gillam ◽  
Manuela Klingler-Hoffmann ◽  
Hugo Albrecht ◽  
Anton Blencowe

Synthetic polypeptides and polymer-peptide hybrid materials have been successfully implemented in an array of biomedical applications owing to their biocompatibility, biodegradability and ability to mimic natural proteins. In addition, these materials have the capacity to form complex supramolecular structures, facilitate specific biological interactions, and incorporate a diverse selection of functional groups that can be used as the basis for further synthetic modification. Like conventional synthetic polymers, polypeptide-based materials can be designed to respond to external stimuli (e.g., light and temperature) or changes in the environmental conditions (e.g., redox reactions and pH). In particular, pH-responsive polypeptide-based systems represent an interesting avenue for the preparation of novel drug delivery systems that can exploit physiological or pathological pH variations within the body, such as those that arise in the extracellular tumour microenvironment, intracellularly within endosomes/lysosomes, or during tissue inflammation. Here, we review the significant progress made in advancing pH-responsive polypeptides and polymer-peptide hybrid materials during the last five years, with a particular emphasis on the manipulation of ionisable functional groups, pH-labile linkages, pH-sensitive changes to secondary structure, and supramolecular interactions.


2021 ◽  
pp. 116529
Author(s):  
Magdalena Kowalska ◽  
Marcin Broniatowski ◽  
Marzena Mach ◽  
Łukasz Płachta ◽  
Paweł Wydro

2019 ◽  
Vol 136 (26) ◽  
pp. 47709 ◽  
Author(s):  
Haibo Long ◽  
Zhiqiang Wu ◽  
Qianqian Dong ◽  
Yuting Shen ◽  
Wuyi Zhou ◽  
...  

2016 ◽  
Vol 40 (3) ◽  
pp. 1997-2006 ◽  
Author(s):  
Kaustuv Banerjee ◽  
Kumar Biradha

The ligands containing chelating as well as exodentate functional groups were shown to form functional coordination polymers and heterometallic gels.


2020 ◽  
Vol 7 (4) ◽  
pp. 229-232
Author(s):  
O. A. Karsakova ◽  
M. V. Kuzmin

In this work, photocurable protective coatings based on methacrylic acid esters have been developed and their physical and mechanical properties have been investigated. The photocurable compositions were obtained by mixing at different ratios the following methacrylic acid esters: polyethylene glycol dimethacrylate 400 and triethylene glycol dimethacrylate ether, polyethylene glycol dimethacrylate 400 and oligourethane dimethacrylate, polyethylene glycol dimethacrylate 400 and pentaerythritol tetraacrylate. For the obtained compositions, the viscosity was studied using a Brookfield rotary viscometer. To initiate polymerization, a mixture of initiators was used: benzoyl peroxide and benzoin. Curing of the obtained compositions was carried out under the influence of UV rays for 2-5 minutes. For photo-cured compositions, their physical and mechanical properties have been studied. It was found that the composition based on polyethylene glycol dimethacrylate modified with triethylene glycol dimethacrylate at a ratio of 70:30 has the highest strength.


Author(s):  
Inna Slepchuk ◽  
Olga Ya. Semeshko ◽  
Yuliya G. Saribekova ◽  
Irina N. Kulish ◽  
Igor V. Gorokhov

Results of study of influence of amount of functional groups of glycidyl ethers on characteristics of the spatial grid of crosslinked polyurethane polymer are presented. Parameters of a three-dimensional spatial grid of investigated samples of polymeric films and their physical and mechanical properties were determined by a method of equilibrium swelling in organic solvents.


2016 ◽  
Vol 85 ◽  
pp. 401-410 ◽  
Author(s):  
A. Larrañaga ◽  
F. Pompanon ◽  
N. Gruffat ◽  
T. Palomares ◽  
A. Alonso-Varona ◽  
...  

Author(s):  
Dimitri Stanicki ◽  
Lionel Larbanoix ◽  
Sébastien Boutry ◽  
Thomas Vangijzegem ◽  
Indiana Ternad ◽  
...  

Bimodal sub-5 nm superparamagnetic iron oxide nanoparticles (SPIO-5) coated with polyethylene glycol of different chain lengths (i.e. PEG-800, -2000 and -5000) have been prepared and characterized.


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