Poly(vinylidene fluoride-co-chlorotrifluoro ethylene) Nanohybrid Membrane for Fuel Cell
Authors: Vinod K Shahi
Devesh K Avasthi
Pralay Maiti
Karun Kumar Jana
Om Prakash
Journal: ACS Omega (2018)
Discipline: CHEMISTRY
Keywords: nanochannels; polymer/hybrid films; swift heavy ions; chemical etching; nanoparticle
Affiliations: School of Materials Science and Technology, Indian Institute of Technology (BHU), Varanasi 221005, India., Electro-Membrane Processes Division, CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar 364002, Gujarat, India., Amity Institute of Nanotechnology, Amity University, Noida 201313, India.

Abstract:  Through nanochannels are created in the polymer/hybrid films by irradiating swift heavy ions followed by selective chemical etching of the amorphous latent track caused by irradiation. The dimensions of the nanochannels are varied from 30 to 100 nm by either using small (lithium) and large (silver) size of swift heavy ions with high energy (80 MeV) or by embedding few percentage of two-dimensional nanoparticle in the polymer matrix. The side walls of the nanochannels are grafted with polystyrene using the free radicals created during irradiation. Polystyrene graft is functionalized by tagging sulfonate group in the benzene ring of polystyrene to make the nanochannels conducting and hydrophilic. The proof of grafting and functionalization is shown through various spectroscopic techniques. The relaxation behavior and thermal stability of graft polymer within the nanochannel are shown through different thermal measurements. Nanoclay in nanohybrid nucleates the piezoelectric phase in the polymer matrix whose extent is further increased in grafted and functionalized specimen. Functionalized nanochannels exclusively facilitate proton conducting, whereas the remaining part of the film is electroactive, making it as a smart membrane. Greater water uptake, ion exchange capacity (IEC), high activation energy (8.3 √ó 103 J mol-1), and high proton conduction (3.5 S m-1) make these functionalized nanohybrid film a superior membrane. Membrane electrode assembly has been made to check the suitability of these membranes for fuel cell application. Open circuit voltage and potential are significantly high for nanohybrid membrane (0.6 V) as compared to pure polymer (0.53 V). Direct methanol fuel cell testing using the membrane assembly exhibit a considerable high power density of ‚à?00 W m-2, making these developed membranes suitable for fuel cell application and providing the ability to replace standard membrane like Nafion, as the methanol permeability is low, thus raising the higher selectivity parameter of the nanohybrid membrane. 

Retracted: No

PubPeer comments:
 Figure 1A:  SEM images of pure CTFE and NH thin film before and after SHI irradiation at 5 u00d7 107 ions cmu22122 fluence with two different (80 MeV Li3+ and 120 MeV Ag11+) ions, followed by etching, of the indicated specimens. * Red boxes: The CTFE Li irradiated panel looks remarkably similar to the NH Ag irradiated panel, albeit shown in inverse black white color.  , 
 Scale bars looks also questionable, if the intention was to zoom from left to right . , 
 Professor Maiti has asked me to post this response from the first author of this paper:  Response: The original images of the indicated images are shown in left part. Crop and contrast images are shown in the middle part and the section marked in white blocks are presented in the paper. So, it is from two different images taken for the presentation. Two separate original images are obtained from the SEM operator against two different samples (CTFE irradiated with Li ion and NH irradiated with Ag ion).  My (Elisabeth Bik s) response to the response: Despite what the author is claiming here, these appear to be the same images. , 
 The argument given by the 1st author is hard to believe. I prepared a negative + brightness gamma correction for the CTFE (Li ion) SEM image, for comparison with the NH-e (Ag ion) image. It seems to me that both are very similar:  , 
 Although the authors denied that these two panels were the same photo, shown in inverse color, they now issued a Correction, February 2022, found here: https: pubs.acs.org doi 10.1021 acsomega.2c00863  We noticed that Figure 1a in the published paper was inadvertently mislabeled (CTFE-e Li ion and NH-e Ag ion). The authors regret for this unintentional oversight and for any confusion that it has caused. We have provided the correct Figure 1a. This correction does not affect the validity of the results and conclusions of the paper.  ,