1
|
Bhutia SZ, Sukumaran SK, Satapathy DK. Determining the Characteristics of Ultrathin Polymer Films: A Spectroscopic Ellipsometry Approach. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:14153-14165. [PMID: 38914532 DOI: 10.1021/acs.langmuir.4c01761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Ellipsometry is a powerful and convenient technique that is widely used to determine the thickness and optical characteristics of polymer thin films. The determination is accomplished by modeling the measured change in the polarization of an electromagnetic wave upon interacting with the thin film. However, due to the strong statistical correlations between the fit parameters in the model, simultaneous determination of the thickness and the refractive indices of optically anisotropic ultrathin films using ellipsometry remains a challenge. Here, we propose an approach that can be used to obtain reliable values of both the thickness and the optical anisotropy of ultrathin polymer films. The approach was developed by performing spectroscopic ellipsometry measurements on thin films of hydrophobic polystyrene and hydrophilic chitosan of thickness between a few tens to a few hundred nm and whose absolute value of the birefringence differed by approximately an order of magnitude. Careful consideration of the characteristics of the root mean squared error of the fits obtained by modeling the ellipsometry data and the statistical correlations between the fit parameters formed the basis of the proposed approach.
Collapse
Affiliation(s)
- Sonam Zangpo Bhutia
- Soft Materials Laboratory, Department of Physics, IIT Madras, Chennai 600036, India
- Center for Soft and Biological Matter, IIT Madras, Chennai 600036, India
| | - Sathish K Sukumaran
- Graduate School of Organic Materials Science, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510, Japan
| | - Dillip K Satapathy
- Soft Materials Laboratory, Department of Physics, IIT Madras, Chennai 600036, India
- Center for Soft and Biological Matter, IIT Madras, Chennai 600036, India
| |
Collapse
|
2
|
Debta S, Bhutia SZ, Satapathy DK, Ghosh P. Intrinsic-water desorption induced thermomechanical response of hydrogels. SOFT MATTER 2022; 18:8285-8294. [PMID: 36285568 DOI: 10.1039/d2sm01054b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
We report an interplay between the desorption of intrinsic water and relaxation of polymer chains resulting in an unusual thermomechanical response of a hydrogel, wherein the elastic modulus increases in a certain temperature range followed by a sharp decrease with a further increase in temperature. We establish that, in a hydrogel, the desorption of disparate water types having distinct binding energy affects the consolidation and relaxation behaviour of the matrix, which in turn affects the mechanical properties at different temperature ranges. Using temperature-dependent dielectric relaxation spectroscopy and nanoindentation techniques, the chain dynamics and mechanical properties are investigated.
Collapse
Affiliation(s)
- Sanghamitra Debta
- Nano Mechanics Laboratory, Department of Applied Mechanics, IIT Madras, Chennai-600036, India.
| | - Sonam Zangpo Bhutia
- Soft Materials Laboratory, Department of Physics, IIT Madras, Chennai-600036, India.
| | - Dillip K Satapathy
- Soft Materials Laboratory, Department of Physics, IIT Madras, Chennai-600036, India.
| | - Pijush Ghosh
- Nano Mechanics Laboratory, Department of Applied Mechanics, IIT Madras, Chennai-600036, India.
| |
Collapse
|
3
|
Lairenjam PD, Sukumaran SK, Satapathy DK. Modulation of Optical Anisotropy in Chitosan Thin Films: Role of Swelling. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pradipkanti Devi Lairenjam
- Soft Materials Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India
- Molecular Electronics Laboratory, Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
| | - Sathish K. Sukumaran
- Graduate School of Organic Materials Science, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510, Japan
| | - Dillip K. Satapathy
- Soft Materials Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India
| |
Collapse
|
4
|
Murali A, Ganesan M, Satapathy DK, Kumar PBS. Penetrant-Induced Glass-like Transition in Thin Chitosan Films. J Phys Chem B 2021; 125:12617-12626. [PMID: 34730977 DOI: 10.1021/acs.jpcb.1c07903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present the water vapor-induced swelling and the emergence of a penetrant-induced glass-like transition in the substrate-supported glassy chitosan thin films. The time evolution of the film thickness under different levels of relative humidity conditions is measured in real-time using a spectroscopic ellipsometer equipped with a humidity cell. In a dry film, the network of chitosan chains is in a glassy state, and upon exposure to water vapor, initially, the film swells by Fickian diffusion of water molecules, which triggers the structural relaxations of the chains. Under higher humidity conditions, a relatively slower evolution of thickness succeeds the initial rapid swelling due to the non-Fickian sorption of water molecules. The swelling characteristics of the polymer films are accounted for by considering the diffusion-relaxation mechanism of chains in the presence of smaller penetrant molecules. The penetrant-induced glass-like transition (Pg), where the polymer film isothermally transits from a glassy to a rubbery state, is determined for pristine and cross-linked chitosan films. Pg is determined from the abrupt change in the rate of swelling observed upon increasing the relative humidity. Chemical crosslinking has an evident influence on the penetrant-induced glass-like transition of the chitosan films. Pg was found to rise sharply for stiffer films with higher cross-linking density.
Collapse
Affiliation(s)
- Aathira Murali
- Department of Physics, Indian Institute of Technology Palakkad, Kanjikode, Kerala 678623, India
| | - Manikandan Ganesan
- Soft Materials Laboratory, Department of Physics and Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036, India
| | - Dillip K Satapathy
- Soft Materials Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India
| | - P B Sunil Kumar
- Department of Physics, Indian Institute of Technology Palakkad, Kanjikode, Kerala 678623, India
| |
Collapse
|
5
|
Joshi SY, Deshmukh SA. A review of advancements in coarse-grained molecular dynamics simulations. MOLECULAR SIMULATION 2020. [DOI: 10.1080/08927022.2020.1828583] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Soumil Y. Joshi
- Department of Chemical Engineering, Virginia Tech, Blacksburg, VA, USA
| | | |
Collapse
|
6
|
Choi D, Sonkaria S, Fox SJ, Poudel S, Kim SY, Kang S, Kim S, Verma C, Ahn SH, Lee CS, Khare V. Quantum scale biomimicry of low dimensional growth: An unusual complex amorphous precursor route to TiO 2 band confinement by shape adaptive biopolymer-like flexibility for energy applications. Sci Rep 2019; 9:18721. [PMID: 31822722 PMCID: PMC6904763 DOI: 10.1038/s41598-019-55103-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 11/25/2019] [Indexed: 11/24/2022] Open
Abstract
Crystallization via an amorphous pathway is often preferred by biologically driven processes enabling living species to better regulate activation energies to crystal formation that are intrinsically linked to shape and size of dynamically evolving morphologies. Templated ordering of 3-dimensional space around amorphous embedded non-equilibrium phases at heterogeneous polymer─metal interfaces signify important routes for the genesis of low-dimensional materials under stress-induced polymer confinement. We report the surface induced catalytic loss of P=O ligands to bond activated aromatization of C−C C=C and Ti=N resulting in confinement of porphyrin-TiO2 within polymer nanocages via particle attachment. Restricted growth nucleation of TiO2 to the quantum scale (≤2 nm) is synthetically assisted by nitrogen, phosphine and hydrocarbon polymer chemistry via self-assembly. Here, the amorphous arrest phase of TiO2 is reminiscent of biogenic amorphous crystal growth patterns and polymer coordination has both a chemical and biomimetic significance arising from quantum scale confinement which is atomically challenging. The relative ease in adaptability of non-equilibrium phases renders host structures more shape compliant to congruent guests increasing the possibility of geometrical confinement. Here, we provide evidence for synthetic biomimicry akin to bio-polymerization mechanisms to steer disorder-to-order transitions via solvent plasticization-like behaviour. This challenges the rationale of quantum driven confinement processes by conventional processes. Further, we show the change in optoelectronic properties under quantum confinement is intrinsically related to size that affects their optical absorption band energy range in DSSC.
Collapse
Affiliation(s)
- Dahyun Choi
- Department of Materials Engineering, Hanyang University, Ansan, 15588, Republic of Korea
| | - Sanjiv Sonkaria
- Institute of Advanced Machinery and Design, Seoul National University, Daehak-dong, Gwanak-gu, Seoul, 151-742, Republic of Korea
| | - Stephen J Fox
- Bioinformatics Institute (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore, 138671, Singapore.,Department of Biological Sciences, National University of Singapore, 16 Science Drive, Singapore, 117558, Singapore.,School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore
| | - Shivraj Poudel
- Department of Mechanical and Aerospace Engineering, Seoul National University, Daehak-dong, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Sung-Yong Kim
- Department of Mechanical and Aerospace Engineering, Seoul National University, Daehak-dong, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Suhee Kang
- Department of Materials Engineering, Hanyang University, Ansan, 15588, Republic of Korea
| | - Seheon Kim
- Department of Mechanical and Aerospace Engineering, Seoul National University, Daehak-dong, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Chandra Verma
- Bioinformatics Institute (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore, 138671, Singapore.,Department of Biological Sciences, National University of Singapore, 16 Science Drive, Singapore, 117558, Singapore.,School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore
| | - Sung Hoon Ahn
- Institute of Advanced Machinery and Design, Seoul National University, Daehak-dong, Gwanak-gu, Seoul, 151-742, Republic of Korea. .,Department of Mechanical and Aerospace Engineering, Seoul National University, Daehak-dong, Gwanak-gu, Seoul, 08826, Republic of Korea.
| | - Caroline Sunyong Lee
- Department of Materials Engineering, Hanyang University, Ansan, 15588, Republic of Korea.
| | - Varsha Khare
- Department of Materials Engineering, Hanyang University, Ansan, 15588, Republic of Korea.
| |
Collapse
|