Department of Chemistry

As part of the 13th edition of the Bengaluru India Nano 2024, heralded by Bharat Ratna recipient and renowned chemist Prof. C N R Rao, SRM University-AP hosted “Nano Jatha“, an intensive science outreach programme, catering to educate undergraduate graduates on the emerging trends of nanotechnology, on July 20, 2024. The Nano Jatha programme organised, aimed to raise awareness on nanoscience and technology through technical presentations by expert scientists and a distinctive live experiment demonstration of nano kits focused on showcasing nanoscience ideas.

The event featured two expert talks by eminent dignitaries. Prof. B L V Prasad, Director-Centre for Nano and Soft Matter Sciences (CeNS), Department of Science and Technology, Govt. of India, also serving as the Nodal Officer for organising Nano Jatha events, delivered a session on the introduction to nanoscience and technology. “Nanoscience and technology are often foretold as the technology of the future. This multidimensional technology will revolutionise our understanding of every natural phenomenon and every aspect of human life,” remarked Prof. Prasad in his session.

Prof. C P Rao, Senior Professor at the Department of Chemistry, presented the second expert talk on the applications of nanomaterials. The session delved into the properties of covalent molecules and its assemblage leading to cutting-edge technology. The programme also featured an exhibition were experiments on Gold nanoparticle; Galvanization reaction between metals; Piezoelectric pavement for futuristic applications; Humidity sensors for real-world applications and many more were displayed.

Prof. C V Tomy, Dean-School of Engineering & Sciences and Dr Pardha Saradhi Maram, Head-Department of Chemistry, emphasised that the Nano Jatha exemplified the university’s commitment to hands-on learning in science, specifically nanotechnology.They commented that the Department of Chemistry is dedicated to fostering scientific knowledge and igniting passion for chemistry among students and educators alike and will continue to organise events like Nano Jatha, conferences, workshops, and Faculty Development Programmes to achieve the same.

Over 300 students from 7 regional colleges in Andhra Pradesh participated in the programme, displaying their zeal in the discussions and nano kit demonstrations. The event was well executed benefitting the student community significantly in understanding various emerging fields in science and technology.

Dr Chinmoy Das, Assistant Professor at the Department of Chemistry at SRM University-AP, has made an impactful contribution with the publication of his research paper, “Insights into the Mechanochemical Glass Formation of Zeolitic Imidazolate Frameworks” in the prestigious Angewandte Chemie International Edition with an impact factor of 16.6. His paper unveils a rapid, eco-friendly, and efficient mechanochemical approach to transform glasses from their crystalline zeolitic imidazolate frameworks. This pioneering work opens new doors for sustainable and effective glass formation, showcasing the power of innovation in the field of chemistry.

Abstract:

We describe a rapid, ecofriendly, and efficient mechanochemical approach to transform glasses from their crystalline zeolitic imidazolate frameworks (ZIFs). We exposition mechanochemical technique through which the traditional melt-quench preparation of glassy phases can be replaced. In this study, we explore that Zn(II), Co(II), and Cu(II)- based crystalline ZIFs transformed into the glassy phases within five minutes through the mechanical ball milling technique. The appearance of glass transition temperature(T g ) upon mechanical milling of crystalline states demonstrated by different characterization techniques, such as X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), simultaneous thermogravimetric and differential thermal analyses (TG/DTA), scanning electron microscopy (SEM), X-ray total scattering and its deduced pair distribution functions (PDFs). We characterized the porosity and density of the glassy phases through CO 2 gas sorption techniques which aligned with the observation of thermal, structural, and textural features of the ZIFs after varying ball milling times beyond five minutes.

Practical implementation

We can prepare bulk ZIF glasses within five minutes of the mechanochemical approach that will guide the greater feasibility to produce the glass materials for industrial implications. In addition, the greater the accessibility of glassy materials, the greater the fabrication of glassy materials-based device fabrication.

Collaborations

This article has been published with the collaboration of Prof. Sebastian Henke (Henke Group), Department of Chemistry and Chemical Biology, TU Dortmund University, Dortmund, Germany.

Future Research Plans

Recently, we established our research group in SRM University-AP, and our group has started to explore an emergent research area of crystal-glass composite materials towards the applications of atmospheric water harvesting, solid-state electrolytes (Alkali and Alkaline metal ions-based), photovoltaics, and conversion of gaseous Carbon-dioxide molecules to industrially relevant liquids, such as methanol or ethanol.

• Figure 1. (A) Single crystal structures of various ZIFs indicated in the figure. (B) Schematic representation of the traditional route to ZIF glass formation (red line) and the mechanochemical vitrification approach followed in this work (blue line). (C) PXRD patterns of the pristine ZIF polycrystalline materials and after five minutes of mechanical ball milling.

The Department of Chemistry and RARE Lab are excited to announce a groundbreaking advancement in the field of analytical detection. Researchers Dr Rajapandiyan Panneerselvan, Asst. Professor and Ph.D scholars, Ms Arunima Jinachandran and Ms Jayasree Kumar have developed a novel method for detecting nitrofurazone (NFZ) using three-dimensional silver nanopopcorns (Ag NPCs) on a flexible polycarbonate membrane (PCM) in their paper “Silver nanopopcorns decorated on flexible membrane for SERS detection of nitrofurazone” published in Microchimica Acta. This innovative technique leverages the power of surface-enhanced Raman spectroscopy (SERS) to provide a highly sensitive and practical solution for detecting NFZ on various surfaces, including fish.

Nitrofurazone (NFZ) is an antibiotic commonly used in veterinary medicine that poses significant health risks if residues enter the food chain. Despite regulatory bans, its illegal use continues, necessitating highly sensitive detection methods. While effective, traditional methods such as high-performance liquid chromatography and mass spectrometry are often costly and labor-intensive. The new SERS-based method offers a more efficient and straightforward alternative.

Abstract

The synthesis of three-dimensional silver nanopopcorns (Ag NPCs) onto a flexible polycarbonate membrane (PCM) for the detection of nitrofurazone (NFZ) on fish surfaces by surface-enhanced Raman spectroscopy (SERS) is presented. The proposed flexible Ag-NPCs/PCM SERS substrate exhibits significant Raman signal intensity enhancement with a measured enhancement factor of 2.36 × 10^6. This enhancement is primarily attributed to the hotspots created on Ag NPCs, which include numerous nanoscale protrusions and internal crevices distributed across the surface. The detection of NFZ using this flexible SERS substrate demonstrates a low limit of detection (LOD) of 3.7 × 10^−9 M and uniform, reproducible Raman signal intensities with a relative standard deviation below 8.34%. The substrate also exhibits excellent stability, retaining 70% of its efficacy even after 10 days of storage. Notably, the practical detection of NFZ in tap water, honey water, and fish surfaces achieves LOD values of 1.35 × 10^−8 M, 5.76 × 10^−7 M, and 3.61 × 10^−8 M, respectively, highlighting its effectiveness across different sample types. The developed Ag-NPCs/PCM SERS substrate presents promising potential for the sensitive SERS detection of toxic substances in real-world samples.

Methodology

The synthesis involves creating silver nanopopcorns on a flexible polycarbonate membrane using a simple chemical method. The resulting Ag NPCs exhibit high surface roughness with numerous nanoscale features that enhance the Raman signal. This flexible substrate can easily collect samples from irregular surfaces without requiring extensive preparation.

This SERS substrate can detect NFZ in various real-world samples, including:

• Tap water
• Honey water
• Fish surfaces

The method’s sensitivity and ease of use make it a promising tool for ensuring food safety and monitoring environmental contaminants.

The Department believes this development will significantly impact public health by providing a reliable and accessible method for detecting harmful substances in the food chain.

Read more

The Department of Chemistry is thrilled to announce the paper “Mechanochemically-induced glass formation from two-dimensional hybrid organic-inorganic perovskites”, published by Dr Chinmoy Das, Assistant Professor in the reputed Q1 Journal Chemical Science with an 8.4 Impact Factor. This groundbreaking research introduces a novel method for transforming crystalline phases into glasses through mechanochemical processes. This environmentally friendly and efficient method opens new doors for manufacturing glasses, revolutionising traditional processes. This remarkable research celebrates this extraordinary blend of chemistry, physics, and innovation!

Abstract

The first mechanochemically-induced hybrid organic-inorganic perovskites (HOIPs) crystal-to-glass transformation was reported as a quick, environmentally friendly, and productive method of making glasses. Within ten minutes of mechanical ball milling, the crystalline phase transformed into the amorphous phase, demonstrating glass transition behaviour as shown by thermal analysis methods. The microstructural evolution of amorphization was studied using time-resolved in situ ball-milling with synchrotron powder diffraction. The results indicated that energy may accumulate as crystal defects because the crystallite size reaches a comminution limit before the amorphization process is finished. The limited short-range order of amorphous HOIPs was discovered through total scattering experiments, and photoluminescence (PL) and ultraviolet-visible (UV-vis) spectroscopy were used to examine their optical characteristics.

Explanation of the research in layperson’s terms

Crystalline inorganic perovskites (general chemical formula is ABX3, where A and B are cations, and X is anion) are generally known for their unique optoelectronic applications, such as solar cells, photodetectors, and LEDs (light emitting diodes). In this research, Dr Das revealed hybrid materials comprised of organic linkers and inorganic nodes, which constitute hybrid organic-inorganic perovskites (HOIPs). The research demonstrated a rapid and environment-friendly (mechanochemically ball milling assisted) synthetic approach to transform the crystalline phase to its non-crystalline/amorphous phase. Interestingly, the amorphous phase of HOIPs showed temperature-dependent glass transition temperature (Tg) at very low temperatures, ~50 C. The structure of the HOIP glasses has been characterised through total-X-ray diffraction studies and pair-distribution functions. The crystalline and glassy HOIPs showed optical properties, which were studied by photoluminescence (PL) and ultraviolet-visible (UV-vis) spectroscopy.

Figure 1. Single crystal structures of (A) (S-NEA)2PbBr4 and (B) (rac-NEA)2PbBr4. Pb, Br, C, N and H atoms are represented by purple, brown, pink, blue, and grey colours, respectively. (C) Schematic illustration of the microstructural evolution on 2D HOIPs upon ball-milling. (D) UV-Vis and (E) photoluminescent properties of crystalline (S-NEA)2PbBr4 (purple) and glassy (S-NEA)2PbBr4 (blue) HOIPs.

Practical implementation/ social implications of your research

Through the mechanochemical approach, we prepared novel hybrid organic-inorganic perovskite (HOIP) glasses within ten minutes, showing the greater feasibility of processing the glass material for industrial implication. On the other hand, we also demonstrated that the HOIP glasses showed photoluminescence properties, which would enable us to fabricate the device for solar cells, photodetectors, LEDs and many more.

Collaborations

• Department of Materials Science and Metallurgy, University of Cambridge, United Kingdom.

The Department of Chemistry has established a research group at SRM University-AP, and the group has started to explore an emergent research area of crystal-glass composite materials towards the applications of atmospheric water harvesting, solid-state electrolytes, photovoltaics, and conversion of gaseous Carbon-dioxide molecules to industrially relevant liquids, such as methanol or ethanol.

Any interested candidate can reach out to Dr Chinmoy for exciting projects.