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Kant M.B.,University of Pune | Shinde S.D.,University of Pune | Bodas D.,Agharkar Research Institute | Patil K.R.,Center for Materials Characterization | And 3 more authors.
Applied Surface Science | Year: 2014

This paper discusses microfabrication process for benzophenone doped polydimethylsiloxane (PDMS) using laser lithography. KrF excimer laser of 248 nm with 20 ns pulse width at repetition rate of 1 Hz was used for microfabrication of undoped and benzophenone doped PDMS. The doped-PDMS shows sensitivity below 365 nm, permitting processing under ambient light. The analysis of etch depth revealed that doped PDMS shows self developable sensitivity at lower fluence of ∼250 mJ/cm2. The unexposed and exposed surface was studied using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and Scanning electron microscopy (SEM). Spectrocopic analysis indicated increase in CO, CO, SiO3 and SiO4 bonding at the expense of SiC and SiO2 bonds of PDMS. In case of laser exposed doped-PDMS, removal of benzophenone from probe depth of spectroscopy was observed. Whereas the surface morphology of exposed and unexposed doped-PDMS was observed to be same, indicating clean development of PDMS micropatterns. The present study indicates that addition of 3.0 wt.% benzophenone in PDMS enhance self development sensitivity of PDMS. The self developable results on doped-PDMS are quite encouraging for its potential use in point of care Lab-On-Chip applications, for fabricating micropatterns using direct write laser lithography technology. © 2014 Elsevier B.V. Source


Das U.K.,Indian Association for The Cultivation of Science | Puranik V.G.,Center for Materials Characterization | Dastidar P.,Indian Association for The Cultivation of Science
Crystal Growth and Design | Year: 2012

Earlier studies revealed that primary ammonium dicarboxylate (PAD) salts possessed gelling ability, and many such salts displayed a 1D columnar hydrogen bonded network (observed in primary ammonium monocarboxylate (PAM) salts) on either side of the dicarboxylate end of the anion. In the present study, a new series of diprimary ammonium monocarboxyate (DPAM) salts have been prepared with the aim of achieving supramolecular synthon transferability (the same 1D columnar hydrogen PAM bonded network on either side of the diammonium cation) in these salts. Single crystal X-ray diffraction studies revealed that, in 47% of the DPAM salts, such supramolecular synthon transferability indeed took place. Some of the DPAM salts also showed gelation ability. The gels were characterized by DSC, rheology, electron microscopy, and atomic force microscopy. Structure property correlation using single crystal and powder X-ray diffraction data on a selected gel was also attempted. © 2012 American Chemical Society. Source


Kale S.S.,CSIR - National Chemical Laboratory | Kunjir S.M.,CSIR - National Chemical Laboratory | Gawade R.L.,Center for Materials Characterization | Puranik V.G.,Center for Materials Characterization | And 2 more authors.
Chemical Communications | Year: 2014

This communication describes the influence of β-aminobenzenesulfonic acid (SAnt) on the conformational preferences of hetero foldamers. The designed (Aib-SAnt-Aib)n and (Aib-SAnt-Pro) n oligomers display a well-defined folded conformation featuring intramolecular mixed hydrogen bonding (7/11) and intra-residual (6/5) H-bonding interactions, respectively. © 2014 The Royal Society of Chemistry. Source

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