scholarly journals Preparation of Composite Materials from Self-Assembled Chitin Nanofibers

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3548
Author(s):  
Jun-ichi Kadokawa

Although chitin is a representative abundant polysaccharide, it is mostly unutilized as a material source because of its poor solubility and processability. Certain specific properties, such as biodegradability, biocompatibility, and renewability, make nanofibrillation an efficient approach for providing chitin-based functional nanomaterials. The composition of nanochitins with other polymeric components has been efficiently conducted at the nanoscale to fabricate nanostructured composite materials. Disentanglement of chitin microfibrils in natural sources upon the top-down approach and regeneration from the chitin solutions/gels with appropriate media, such as hexafluoro-2-propanol, LiCl/N, N-dimethylacetamide, and ionic liquids, have, according to the self-assembling bottom-up process, been representatively conducted to fabricate nanochitins. Compared with the former approach, the latter one has emerged only in the last one-and-a-half decade. This short review article presents the preparation of composite materials from the self-assembled chitin nanofibers combined with other polymeric substrates through regenerative processes based on the bottom-up approach.

2020 ◽  
Vol 8 (31) ◽  
pp. 10837-10843
Author(s):  
Zhichun Shangguan ◽  
Chunyang Yu ◽  
Chen Li ◽  
Xianhui Huang ◽  
Yiyong Mai ◽  
...  

We show the strategy of introducing azobenzene groups into graphene nanoribbons (GNRs), which not only endows GNRs with fast photo-responsiveness but also induces the self-assembly of the GNRs into ultra-long nanowires.


2015 ◽  
Vol 6 (9) ◽  
pp. 5114-5119 ◽  
Author(s):  
Alexander Stephenson-Brown ◽  
Aaron L. Acton ◽  
Jon A. Preece ◽  
John S. Fossey ◽  
Paula M. Mendes

A hierarchical bottom-up route exploiting reversible covalent interactions with boronic acids and so-called click chemistry for selective glycoprotein detection is described. The self-assembled and imprinted surfaces confer high binding affinities, nanomolar sensitivity, exceptional glycoprotein specificity and selectivity.


Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2805
Author(s):  
Chie Kojima ◽  
Tomoka Hirose ◽  
Risa Katayama ◽  
Akikazu Matsumoto

2-Methacryloyloxyethyl phosphorylcholine (MPC) polymers have been used as a coating agent on medical devices and as a carrier in drug delivery systems (DDSs). Paclitaxel (PTX) is a water-insoluble anticancer drug whose solubilizer is necessary for administration. Block and random copolymers composed of hydrophilic MPC and butyl methacrylate, named PMB, show different properties, depending on the polymer sequence and MPC content. In the present study, we used amphiphilic MPC polymers comprising hydrophobic dodecyl methacrylate (DMA). The self-assembling properties and PTX solubilization of random and block poly(MPC-co-DMA)s (rPMDs and bPMDs) with different compositions were examined and compared. rPMDs with high DMA content formed large and relatively loose self-assembled structures, which solubilized PTX. However, bPMDs formed small and compact self-assembled structures with poor PTX solubilization. PTX solubilized by PMB with small and loose self-assembled structures showed efficient drug action, similar to free PTX; however, rPMDs fell short of demonstrating PTX efficiency. Our results suggest that the self-assembling properties and the hydrophobicity of amphiphilic MPC polymers largely affect PTX solubilization as well as drug action, which is required to be controlled by the polymer sequence, as well as the structure and composition of the hydrophobic monomer for efficient DDS.


2005 ◽  
Vol 2005 (7) ◽  
pp. 449-451 ◽  
Author(s):  
Haolin Tang ◽  
Zhiping Luo ◽  
Mu Pan ◽  
San Ping Jiang ◽  
Zhengcai Liu

A catalyst-coated membrane (CCM) for a proton exchange membrane fuel cell (PEMFC) with Pt loading of 2.8 μg/cm2 have been prepared by self-assembling charged Pt particles on a sulfonic acid function group, SO3-, on the membrane surface. Proton conductivity of the as-obtained CCM is 0.0932 S/cm. Half-cell polarisation showed that the self-assembled membrane is electrochemical active. Electrochemical characterisation of the self-assembled electrode showed that the Pt-PDDA nanoparticles were electrocatalytic active. The performance of self-assembled MEA with a Pt loading of 2.8 μg/cm2 achieved 2.3 mW/cm2. This corresponds to Pt utilisation of 821 W per 1 g Pt. The results demonstrated the feasibility of the formation of monolayered Pt nanoparticle structure on the membrane interface. Such a monolayered structure could offer a powerful tool in fundamental studies of polymer electrolyte systems.


2005 ◽  
Vol 896 ◽  
Author(s):  
Senthil Subramanium ◽  
Shameem Hasan ◽  
Shantanu Bhattacharya ◽  
Yuanfang Gao ◽  
Steve Apperson ◽  
...  

AbstractCurrent approaches of mixing fuel and oxidizer nanoparticles or adding fuel nanoparticles to oxidizer gel lead to an overall reduced interfacial area of contact between them and thus, limit their burn rates severely. We have developed an approach of self-assembling fuel nanoparticles around an oxidizer matrix using a monofunctional polymer, poly(4)-vinyl pyridine (P4VP). The polymer has been used to accomplish binding of fuel and oxidizer in a molecularly engineered manner. We use composite of Al-nanoparticles and CuO nanorods for executing this self-assembly. TEM images of this composite confirms the self-assembly of Al-nanoparticles around the oxidizer nanorods. The burn rate of self-assembled composite has been found significantly higher than that of the composite prepared by simple mixing.


Author(s):  
Haolin Tang ◽  
Mu Pan ◽  
Shichun Mu ◽  
Zhaohui Wan ◽  
Runzhang Yuan

Direct liquid fuel cells have attracted intensive research because of the promised application in Portable Fuel Cell Systems. Liquid fuel crossover through the proton exchange membranes (PEMs, e.g. Nafion™ membrane) is one of the major obstacles that currently prevent the widespread commercial applications of direct liquid fuel cell. In this paper, PEMs constructed by self-assembling metal nanoparticles on Nafion™ membranes were prepared to probe the crossover behaviors. The results show that the fuel crossover has a remarkable decrease comparing with the original PEMs. This satisfactory performance gives the self-assembled PEMs a promised prospect in direct liquid fuel cells.


Soft Matter ◽  
2010 ◽  
Vol 6 (21) ◽  
pp. 5298 ◽  
Author(s):  
Chao Zhong ◽  
Ashleigh Cooper ◽  
Adnan Kapetanovic ◽  
Zhihua Fang ◽  
Miqin Zhang ◽  
...  

MRS Advances ◽  
2020 ◽  
Vol 5 (64) ◽  
pp. 3507-3520
Author(s):  
Chunhui Dai ◽  
Kriti Agarwal ◽  
Jeong-Hyun Cho

AbstractNanoscale self-assembly, as a technique to transform two-dimensional (2D) planar patterns into three-dimensional (3D) nanoscale architectures, has achieved tremendous success in the past decade. However, an assembly process at nanoscale is easily affected by small unavoidable variations in sample conditions and reaction environment, resulting in a low yield. Recently, in-situ monitored self-assembly based on ion and electron irradiation has stood out as a promising candidate to overcome this limitation. The usage of ion and electron beam allows stress generation and real-time observation simultaneously, which significantly enhances the controllability of self-assembly. This enables the realization of various complex 3D nanostructures with a high yield. The additional dimension of the self-assembled 3D nanostructures opens the possibility to explore novel properties that cannot be demonstrated in 2D planar patterns. Here, we present a rapid review on the recent achievements and challenges in nanoscale self-assembly using electron and ion beam techniques, followed by a discussion of the novel optical properties achieved in the self-assembled 3D nanostructures.


2018 ◽  
Author(s):  
Claudia Contini ◽  
Russell Pearson ◽  
Linge Wang ◽  
Lea Messager ◽  
Jens Gaitzsch ◽  
...  

<div><div><div><p>We report the design of polymersomes using a bottom-up approach where the self-assembly of amphiphilic copolymers poly(2-(methacryloyloxy) ethyl phosphorylcholine)–poly(2-(diisopropylamino) ethyl methacrylate) (PMPC-PDPA) into membranes is tuned using pH and temperature. We study this process in detail using transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) spectroscopy, dynamic light scattering (DLS), and stop-flow ab- sorbance disclosing the molecular and supramolecular anatomy of each structure observed. We report a clear evolution from disk micelles to vesicle to high-genus vesicles where each passage is controlled by pH switch or temperature. We show that the process can be rationalised adapting membrane physics theories disclosing important scaling principles that allow the estimation of the vesiculation minimal radius as well as chain entanglement and coupling. This allows us to propose a new approach to generate nanoscale vesicles with genus from 0 to 70 which have been very elusive and difficult to control so far.</p></div></div></div>


2018 ◽  
Author(s):  
Claudia Contini ◽  
Russell Pearson ◽  
Linge Wang ◽  
Lea Messager ◽  
Jens Gaitzsch ◽  
...  

<div><div><div><p>We report the design of polymersomes using a bottom-up approach where the self-assembly of amphiphilic copolymers poly(2-(methacryloyloxy) ethyl phosphorylcholine)–poly(2-(diisopropylamino) ethyl methacrylate) (PMPC-PDPA) into membranes is tuned using pH and temperature. We study this process in detail using transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) spectroscopy, dynamic light scattering (DLS), and stop-flow ab- sorbance disclosing the molecular and supramolecular anatomy of each structure observed. We report a clear evolution from disk micelles to vesicle to high-genus vesicles where each passage is controlled by pH switch or temperature. We show that the process can be rationalised adapting membrane physics theories disclosing important scaling principles that allow the estimation of the vesiculation minimal radius as well as chain entanglement and coupling. This allows us to propose a new approach to generate nanoscale vesicles with genus from 0 to 70 which have been very elusive and difficult to control so far.</p></div></div></div>


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