01975nas a2200169   4500008004100000245011700041210006900158260000800227300001600235490000700251520131000258100002101568700002201589700004301611700002701654856012401681       2016                        eng d00aTemplate determines whether chemically identical nanoparticle scaffolds show elastic recovery or plastic failure0 aTemplate determines whether chemically identical nanoparticle sc  cNOV  a11623-116300 v323 a<p>Subtle variations in the preparation of ice-templated nanoparticle assemblies yield monoliths that are chemically identical but exhibit qualitatively different mechanical behavior. We ice template aqueous dispersions to prepare macroporous monoliths largely comprising silica nanoparticles held together by a crosslinked polymer mesh. When the polymer is crosslinked in the presence of ice crystals, we obtain an elastic sponge that is capable of recovery after imposition of large compressive strains (up to 80%). If, however, the ice is lyophilized before the polymer is crosslinked, we obtain a plastic monolith that fails even for modest strains (less than 10%). The elastic sponge and the plastic monolith are chemically identical; they have the same organic content, the same ratio of polymer to crosslinker, and the same average crosslink density. Atomic force microscopy (AFM) was used to probe the local mechanical properties of the crosslinked polymer mesh. These measurements indicate that plastic monoliths dissipate significantly more energy and have a larger spatial variation in local mechanical response relative to the elastic sponges. We believe that this behavior might correlate with a wider spatial distribution of crosslinks in plastic scaffolds relative to elastic scaffolds.</p>1 aSuresh, Karthika1 aPatil, Shivprasad1 aRajamohanan, Pattuparambil, Ramanpilla1 aKumaraswamy, Guruswamy  uhttps://library.ncl.res.in/content/template-determines-whether-chemically-identical-nanoparticle-scaffolds-show-elastic01889nas a2200229   4500008004100000245010700041210006900148260000800217300001000225490000800235520107000243100002801313700002201341700002101363700001501384700002901399700002601428700002201454700002601476700003101502856012601533       2018                        eng d00a Functionalized carbon nanotube reinforced polymer nanocomposite microcapsules with enhanced stiffness0 aFunctionalized carbon nanotube reinforced polymer nanocomposite   cAUG  a82-890 v5503 aMicrocapsules with tunable mechanical properties are highly desirable in pressure sensitive applications. We report here a facile approach to prepare polyurea/multiwall carbon nanotube (MWCNTs) nanocomposite microcapsules (MICs) with enhanced stiffness. A model compound dimethyl phthalate (DMP) was used as core material. MWCNTs were modified with reactive functional groups namely carboxyl (-COOH), amines (-NH2), and isocyanates (-NCO) to ensure a stronger interface between polymer wall and MWCNTs. Functionalization of MWCNTs was corroborated by Fourier transformed infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) was employed to study the surface morphology of MICs. The presence of MWCNTs in the microcapsule wall was confirmed by transmission electron microscopy (TEM). MICs with functionalized MWCNTs show almost 100% increase in stiffness with respect to pristine capsules. All MICs show 92-97 +/- 1% encapsulation efficiency. The approach used in this paper can be broadly utilized to tune the mechanical properties of the microcapsules.1 aJagtap, Siddheshwar, B.1 aPatil, Vishal, D.1 aSuresh, Karthika1 aRam, Farsa1 aMohan, Muthu, Subramania1 aRajput, Shatruhan, S.1 aPatil, Shivprasad1 aShukla, Parshuram, G.1 aShanmuganathan, Kadhiravan  uhttps://library.ncl.res.in/content/functionalized-carbon-nanotube-reinforced-polymer-nanocomposite-microcapsules-enhanced02695nas a2200181   4500008004100000022001400041245009400055210006900149260000900218300001400227490000700241520205600248100002102304700002902325700002202354700001702376856012002393       2021                        eng d  a0743-746300aMechanism of adhesion of natural polymer coatings to chemically modified siloxane polymer0 aMechanism of adhesion of natural polymer coatings to chemically   cMAR   a2974-29840 v373 a<p>Surface coatings play an important role in improving the performance of biomedical implants. Polydimethylsiloxane (PDMS) is a commonly used material for biomedical implants, and surface-coated PDMS implants frequently face problems such as delamination or cracking of the coating. In this work, we have measured the performance of nano-coatings of the biocompatible protein polymer silk fibroin (SF) on pristine as well as modified PDMS surfaces. The PDMS surfaces have been modified using oxygen plasma treatment and 3-amino-propyltriethoxy-silane (APTES) treatment. Although these techniques of PDMS modification have been known, their effects on adhesion of SF nano-coatings have not been studied. Interestingly, testing of the coated samples using a bulk technique such as tensile and bending deformation showed that the SF nano-coating exhibits improved crack resistance when the PDMS surface has been modified using APTES treatment as compared to an oxygen plasma treatment. These results were validated at the microscopic and mesoscopic length scales through nano-scratch and nano-indentation measurements. Further, we developed a unique method using modified atomic force microscopy to measure the adhesive energy between treated PDMS surfaces and SF molecules. These measurements indicated that the adhesive strength of PDMS-APTES-SF is 10 times more compared to PDMS-O-2-SF due to the higher number of molecular linkages formed in this nanoscale contact. This lower number of molecular linkages in the PDMS-O-2 indicates that only fewer numbers of surface hydroxyl groups interact with the SF protein through secondary interactions such as hydrogen bonding. On the other hand, a larger number of amine groups present on PDMS-APTES surface hydrogen bond with the polar amino acids present on the silk fibroin protein chain, resulting in better adhesion. Thus, APTES modification to the PDMS substrate results in improved adhesion of nano-coating to the substrate and enhances the delamination and crack resistance of the nano-coatings.</p>1 aJoseph, Emmanuel1 aRajput, Shatruhan, Singh1 aPatil, Shivprasad1 aNisal, Anuya  uhttps://library.ncl.res.in/content/mechanism-adhesion-natural-polymer-coatings-chemically-modified-siloxane-polymer02456nas a2200301   4500008004100000022001400041245016000055210006900215260000900284300001600293490000700309520139100316653003101707653003201738653002601770653002801796653002401824653002101848100001701869700002301886700002001909700002901929700001901958700000501977700002201982700002502004856012502029       2021                        eng d  a1944-824400aResistive switching in HfO2-x/La0.67Sr0.33MnO3 heterostructures: an intriguing case of low H-field susceptibility of an E-field controlled active interface0 aResistive switching in HfO2xLa067Sr033MnO3 heterostructures an i  cNOV   a54133-541420 v133 aHigh-performance nonvolatile resistive random access memories (ReRAMs) and their small stimuli control are of immense interest for high-speed computation and big-data processing in the emerging Internet of Things (IoT) arena. Here, we examine the resistive switching (RS) behavior in growth-controlled HfO2/La0.67Sr0.33MnO3 (LSMO) heterostructures and their tunability in a low magnetic field. It is demonstrated that oxygen-deficient HfO2 films show bipolar switching with a high on/off ratio, stable retention, as well as good endurance owing to the orthorhombic-rich phase constitution and charge (de)trapping-enabled Schottky-type conduction. Most importantly, we have demonstrated that RS can be tuned by a very low externally applied magnetic field (similar to 0-30 mT). Remarkably, application of a magnetic field of 30 mT causes RS to be fully quenched and frozen in the high resistive state (HRS) even after the removal of the magnetic field. However, the quenched state could be resurrected by applying a higher bias voltage than the one for initial switching. This is argued to be a consequence of the electronically and ionically ``active'' nature of the HfO2-x/LSMO interface on both sides and its susceptibility to the electric and low magnetic field effects. This result could pave the way for new designs of interface-engineered high-performance oxitronic ReRAM devices.10acharge trapping-detrapping10alow external magnetic field10aoxide-oxide interface10apulsed laser deposition10aresistive switching10aSchottky barrier1 aAntad, Vivek1 aShaikh, Parvez, A.1 aBiswas, Abhijit1 aRajput, Shatruhan, Singh1 aDeo, Shrinivas1 a1 aPatil, Shivprasad1 aOgale, Satishchandra  uhttps://library.ncl.res.in/content/resistive-switching-hfo2-xla067sr033mno3-heterostructures-intriguing-case-low-h-field