L-α-dipalitoylphosphatidylcholine(DPPC) is a phospholipid, and a lung surfactant is used for dielectric surface patterning. In this technique, the self-assembling property of DPPC along with meniscus oscillation, which occurs in LangmuirBlodgett transfer, results in a spatially inhomogeneous distribution of two different phases of DPPC. This way, nanometre height rigid, tightly packed, and durable lateral structures separated by micron size channels are grown on the dielectric surface using the Langmuir-Blodgett deposition technique. The effect of surface modification and deposition parameters on the growth of the patterned surface is studied in detail. A simplified relationship between the surface energy of substrate and deposition parameters is explained in this work. Thus, deposition parameters can be tuned based on the modification of the surface gives more control over the growth of these structures. Lastly, the effect of post-annealing temperatures on the patterned surface is investigated. In conclusion, an easy, affordable, and less timeconsuming method of dielectric surface patterning using phospholipid is investigated, which has potential applications in improving the properties (such as charge mobility and contact resistance) of OFET, TFT and in bioelectronics.
Table of Contents
1. Introduction
1.1. Self-assembly
1.2. DPPC
2. Literature survey
2.1. Stripe pattern formation using Langmuir-Blodgett deposition technique
2.2. Effect of surface treatment on self-organized DPPC monolayer
2.3. Selective deposition of organic molecules onto DPPC templates
2.4. Effect of temperature on self-assembly of amphiphilic molecules
3. Experimental techniques
3.1. Langmuir-Blodgett deposition technique
3.2. Sol-gel technique
3.3. Spin-coating technique
3.4. Atomic force microscopy(AFM)
3.5. Optical Microscopy
3.6. X-ray photoelectron spectroscope(XPS)
3.7. X-ray reflectivity(XRR)
4. Problem Statement
5. Growth of Self-assembled monolayer (SAM) on Mica substrate
5.1. Chemicals and equipment:
5.2. Langmuir monolayer preparation:
5.3. Monolayer transfer on substrate:
5.1. Experimental Results
5.4.1. Pressure - Area Isotherm:
5.4.2. AFM measurement:
5.5. Discussion:
6. Growth of Patterned SAM of DPPC on BTO surface
6.1. Experimental section:
6.1. Results:
6.2.1. XPS measurements:
6.2.2. XRR measurements:
6.2.3. AFM and optical microscopy measurements:
6.3. Discussion:
7. Effect of post-annealing temperature on pattern SAM of DPPC on dielectric surface
7.1. Experimental section:
7.2. Results:
7.3. Discussion:
8. Conclusion
Research Objectives & Topics
The primary aim of this project is to study the growth of patterned self-assembled films of L-α-dipalmitoylphosphatidylcholine (DPPC) on dielectric surfaces using the Langmuir-Blodgett (LB) technique. The research investigates how deposition parameters, surface energy of the substrate, and post-annealing temperatures influence the surface morphology of these patterned structures to improve device performance in microelectronics and bioelectronics.
- Langmuir-Blodgett deposition as a method for surface patterning.
- The influence of substrate surface energy on DPPC monolayer formation.
- Characterization of patterned surfaces using AFM, XPS, XRR, and optical microscopy.
- Investigating the effects of post-annealing temperature on the stability and morphology of DPPC films.
Excerpt from the Book
1. Introduction
Surface patterning is an essential part of science and technology, especially in the field of microelectronics, microfluidic devices, and bioelectronics. It means a modification of surface to fabricate chemically and physically distinct regions on a surface. The method of surface patterning for biomolecules was derived from the microelectronics industry [1][2][3]. When the hand wiring of small and complex electronic devices became difficult, then new methods were developed to pattern nanoscale structures on large substrates in the batch process. Among these, surface patterning using self-assembly is an emerging field and was developed in the last two decades. This method has an advantage over other surface patterning techniques in terms of high throughput, high resolution, low cost, and less time-consuming.
Organic molecules can self-assemble into membrane structures in the living cells. Self-assembly of molecules on the surface was first reported in 1946[4]. Understanding it will help us to study living cells and biomimetic. Day-by-day, the interaction of new organic molecules with different surfaces via self-assembly is being investigated and is a recent topic of interest. Langmuir-Blodgett(LB) deposition is one of the techniques used to study the self-assembly ability of organic molecules. It is also used to transfer Self-assembled monolayer (SAM) on a solid substrate. A basic method of LB deposition involves a one-to-one homogeneous transfer of monolayer. However, by varying specific parameters, a patterned surface is obtained[5][6][7].
Summary of Chapters
1. Introduction: This chapter introduces the importance of surface patterning in modern electronics and outlines the research objective, which focuses on studying the growth of patterned DPPC films.
2. Literature survey: This chapter provides a comparative overview of existing surface patterning methods, specifically focusing on Langmuir-Blodgett deposition and the influence of surface treatments.
3. Experimental techniques: This chapter details the various methodologies used, including the Langmuir-Blodgett deposition technique, Sol-gel, Spin-coating, AFM, Optical Microscopy, XPS, and XRR.
4. Problem Statement: This chapter summarizes the multi-part research project involving the growth of SAM on mica, the patterning on BTO surfaces, and the study of post-annealing effects.
5. Growth of Self-assembled monolayer (SAM) on Mica substrate: This chapter describes the experimental procedure for forming DPPC monolayers on mica and presents analysis results regarding deposition speed and film thickness.
6. Growth of Patterned SAM of DPPC on BTO surface: This chapter presents the results of forming DPPC patterns on Barium titanate substrates, confirmed through XPS, XRR, and microscopic analysis.
7. Effect of post-annealing temperature on pattern SAM of DPPC on dielectric surface: This chapter investigates how different annealing temperatures affect the morphology and stability of the patterned DPPC films.
8. Conclusion: This chapter summarizes the research findings, highlighting that the studied method provides a high-throughput, affordable, and reproducible way to form patterned structures for potential applications.
Keywords
DPPC, Langmuir-Blodgett, Surface Patterning, Self-assembly, Barium Titanate, Dielectric Surface, AFM, XPS, XRR, Monolayer, Thin film, Post-annealing, Nanotechnology, Microelectronics, Bioelectronics
Frequently Asked Questions
What is the core focus of this research?
The research focuses on the fabrication and characterization of patterned self-assembled monolayers of the phospholipid DPPC on dielectric surfaces, specifically investigating how growth parameters and temperature affect the resulting structure.
What are the primary fields of application for this work?
The patterns created have potential applications in improving the performance of organic field-effect transistors (OFETs), thin-film transistors (TFTs), and in the broader field of bioelectronics.
What is the main objective of the thesis?
The objective is to study the growth of patterned self-assembled films of L-α-dipalmitoylphosphatidylcholine (DPPC) using the Langmuir-Blodgett deposition technique and to refine control over these structures through parameters like surface energy and post-annealing temperatures.
Which scientific methods are primarily utilized?
The study utilizes the Langmuir-Blodgett deposition method, supported by Atomic Force Microscopy (AFM), X-ray photoelectron spectroscopy (XPS), X-ray reflectivity (XRR), and optical microscopy for characterization.
What is covered in the main body of the work?
The main body details the growth of SAMs on both mica and Barium titanate surfaces, the determination of deposition parameters, and the investigation of how post-annealing alters the morphology of these patterns.
Which keywords best characterize this research?
Keywords include DPPC, Langmuir-Blodgett, surface patterning, self-assembly, Barium titanate, thin films, and various characterization techniques like AFM and XPS.
Why is the Barium titanate (BTO) surface specifically chosen for this study?
BTO is chosen as a dielectric surface to test the versatility of the self-assembly and patterning method, particularly because its high surface energy influences the phase transition behavior of the DPPC molecules differently than on mica.
How does post-annealing affect the DPPC patterns?
Post-annealing causes irreversible changes in surface morphology, leading to an increase in both the width and height of the DPPC stripes due to reorganization, which can be used to control structural properties.
- Quote paper
- Satyabrat Behera (Author), 2020, Growth of Self-Assembled Patterned Films on Dielectric Surfaces Using Langmuir-Blodgett Deposition Technique, Munich, GRIN Verlag, https://www.grin.com/document/1445647
