https://ir.nctu.edu.tw:443/bitstream/11536/14909/1/000297489400002.pdf

POSS related polymer nanocomposites

Synthesis and applications of hyperbranched polymers

Low-dielectric-constant nanoporous films (dielectric constant, k = 2.4) with thermal integrity and controllable mechanical strength have been prepared by covalently tethering nanoporous polyhedral oligomeric silsesquioxane (POSS) molecules, 1-nm size, to the side chains of polyimide. The tethered POSS molecules in the amorphous polyimide retain a nanoporous crystal structure, but form an additional ordered architecture due to microphase separation. With this approach, the dielectric constant of the film can be tuned by the amount of POSS molecules introduced in the nanocomposite film; the polyimide molecules offer additional advantages of maintaining certain thermal and mechanical strengths.

https://ir.nctu.edu.tw:443/bitstream/11536/27522/1/000185410900024.pdf

Polyimide-Side-Chain Tethered Polyhedral Oligomeric Silsesquioxane Nanocomposites for Low-Dielectric Film Applications

Polyimide-tethered polyhedral oligomeric silsesquioxane, (R7RSi8O12) (POSS), nanocom- posites with well-defined architectures are prepared by the copolymerization reaction of a new type of diamine monomer: POSS-diamine, 4,4'-oxydianiline (ODA), and pyromellitic dianhydride (PMDA). This type of polyimide-side-chain-tethered POSS nanocomposite presents self-assembly characteristics when the amount of POSS exceeds10 mol %, as evidenced by transmission electron microscopy studies. Furthermore, POSS/polyimide nanocomposites have both lower and tunable dielectric constants, with the lowest value of 2.3, and controllable mechanical properties, as compared to that of pure polyimide.

https://ir.nctu.edu.tw:443/bitstream/11536/27326/1/000186857700028.pdf

Synthesis and Dielectric Properties of Polyimide-Tethered Polyhedral Oligomeric Silsesquioxane (POSS) Nanocomposites via POSS-diamine

Nanoporous polyhedral oligomeric silsesquioxanes (POSS) containing amine groups (NH2−POSS) were reacted with poly(amic acid) having anhydride end groups to form porous POSS/polyimide nanocomposites. The van der Waals interaction between tethered POSS molecules is incompatible with the polar−polar interaction of imide segments, resulting in a self-assembled system of zigzag shaped cylinders or lamellas about 60 nm long and 5 nm wide, as determined by transmission electron microscopy. The incorporation of 2.5 mol % nanoporous POSS results in a reduction of the dielectric constant of the polyimide nanocomposite from 3.40 for the pure polyimide to 3.09 without any degradation in mechanical strength.

https://ir.nctu.edu.tw:443/bitstream/11536/27796/1/000183228000025.pdf

Synthesis and dielectric properties of polyimide-chain-end tethered polyhedral oligomeric silsesquioxane nanocomposites

A means of generating foams of high-temperature polymers, polyimides, has been developed for use in dielectric layers in microelectronics. In these systems, the pore sizes generated are in the tens of nanometers range, thus the term “nanofoams”. The foams are generated by preparing phase-separated block copolymers with the majority phase comprised of polyimide and the minor phase consisting of a thermally labile block. Films are cast, solvent is removed, and the copolymers are cured, causing phase separation of the two blocks. The labile blocks are subsequently removed via thermal treatments leaving pores having a size and shape commensurate with the size and shape of the original copolymer morphology. The polyimide derived from pyromellitic dianhydride (PMDA) and 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (4-BDAF) was used as the matrix materials for the generation of nanofoams, and poly(propylene oxide) oligomers were used as the thermally labile constituent. The synthesis and characterization o...

Polyimide Nanofoams Based on Ordered Polyimides Derived from Poly(amic alkyl esters): PMDA/4-BDAF

Ni(II) dithiocarbamate: synthesis, crystal structures, DFT studies and applications as precursors for nickel sulfide and nickel oxide nanoparticles

Synthesis, crystal structure, DFT and Hirshfeld surface analysis of Ni(II) complexes: precursor for nickel sulfide nanoparticles

Single-crystal X-ray diffraction analysis was used to determine the crystal structure of 2-bromopyridinium picrate (2BPP), which was formed using a slow evaporation solution growth approach. It belongs to a triclinic system with the centrosymmetric space group Pī. Supramolecular assembly is constructed by N-H•••O and π•••π stacking interaction. By employing FT-IR analysis to identify the functional groups that are present in the molecule, the band gap energy was calculated by using the Kubelka-Munk algorithm. A study of the intermolecular interactions and crystal packing using Hirshfeld surface analysis, derived by single crystal XRD data, reveals the close contacts associated with strong interactions. Theoretical calculations were done by the density functional theory (DFT) method. 

Synthesis, structural characterization, Hirshfeld surface and theoretical studies of 2-bromopyridinium picrate

The development of smart metering technology empowers power reforms, which allows effective implementation of demand response programs to effectively operate the power grid. The systematic analysis of smart meter data plays a vital role for both consumers and utilities to reduce their costs and improve the efficiency of power management. In this paper, a machine learning algorithm is proposed to recommend the appropriate Demand Response (DR) program for the consumer in a real-time environment, tailored with dynamic pricing. The systematic recommendation can be made by integrating time series forecasting, consumer clustering, and DR analysis. The smart meter data of the 28 consumers for 108 weeks are recorded and applied to the ARIMA time series forecast algorithm. The smart meter data and ARIMA time series forecast data are combined and fed to the Agglomerative Hierarchical clustering algorithm to cluster consumers based on their usage and demand pattern. Clusters are analysed to identify a suitable DR program for the consumer. The results show that the proposed machine learning method effectively clusters consumers and implements the DR program in the smart grid environment.

/pdf/design-of-a-dynamic-demand-response-model-through-ld417e75.pdf

Priya Lakshmanan

Papers

Polyimide Nanofoams Based on Ordered Polyimides Derived from Poly(amic alkyl esters): PMDA/4-BDAF

Ni(II) dithiocarbamate: synthesis, crystal structures, DFT studies and applications as precursors for nickel sulfide and nickel oxide nanoparticles

Synthesis, crystal structure, DFT and Hirshfeld surface analysis of Ni(II) complexes: precursor for nickel sulfide nanoparticles

Synthesis, structural characterization, Hirshfeld surface and theoretical studies of 2-bromopyridinium picrate

Design of a Dynamic Demand Response Model Through Intelligent Clustering Algorithm Based on Load Forecasting in Smart Grid