Nanobiotechnology – Fall 2011 – Take-Home 2
Important Note: The students with the following roll nos. are exempted from answering
this take-home exam as they have secured ≥ 50 % of marks in today’s (15-9-2011) classexam – 35, 76, 93, 118, and 154.
Answer in brief
Sheet No. 1
1. Why should one be studying Nanotechnology and Nanobiotechnology?
2. What is nanotechnology? Answer this question in both technical and nontechnical terms, and consider your answer in terms of science, engineering,
technology, and manufacturing. Consider how nanotechnology is applied to the
problems of energy, water, health, and supercomputing as described in the
‘Foresight Challenges’ (http://www.foresight.org/challenges/index.html).
3. Give an example of a nano-enabled product and write in brief about it (how it is
prepared, uses, applications, etc.) [Answers for these kinds of questions should be
different for each student – If they are the same, it means there is a high chance
the student might have copied from another student – Take care regarding this!]
4. List the different techniques for making nanopores. What happens to the surface
area of a solid when it becomes nanoporous?
5. Why do the properties of materials change at the nanoscale?
6. Which are easier to deform – materials with metallic or ionic bonding? Why?
7. Describe the basic structure of an atom, including nucleus (neutrons and protons),
electrons, and the basic octet rule for electronic bonding. Consider how the
electronic structure of an atom, and the chemical properties that result, affect how
that atom participates in chemical bonding, the types and shapes of molecules that
atom typically forms, and how all these affect nanostructure and chemical
properties.
8. Describe the basic structure of an atom, including nucleus (neutrons and protons),
electrons, and the basic octet rule for electronic bonding. Consider how the
electronic structure of an atom, and the chemical properties that result, affect how
that atom participates in chemical bonding, the types and shapes of molecules that
atom typically forms, and how all these affect nanostructure and chemical
properties.
9. Describe how chemical and molecular bonding occurs, describing all types of
bonds, including covalent, ionic, metallic, hydrogen, and the forces that affect
bonds, such as Van der Walls. Compare and contrast covalent, ionic, metallic,
hydrogen, and ‘pi’ bonds (for example carbon). Consider how molecular bonding
affects nanostructures, and comment on carbon bonds in CNT/MWNT and silicon
bonding (semiconductor). With respect to semiconduction, briefly describe the
concept of band gap in semiconduction, and compare and contrast carbon and
silicon.
10. Describe the concept of nanoscale emergence. Specifically, discuss the
observation of macroscopic phenomena including biology and natural systems
that emerge from smaller systems such as physical, chemical, and
macromolecular systems. You are encouraged to begin your answer from the
smallest components and forces in the universe that you are able to explain, and
then expand outwards into physics, chemistry, biology, etc. (Hint - there is a
website and exhibit called ‘Powers of 10’ that you can couple with the ‘concept of
networks’ to answer this question. Also, research emergence at
http://emergence.org/ and http://en.wikipedia.orci/wiki/Emercience). This is one
of the most discussed topics in nanoscale education - and the goal of this question
is to get you thinking about how macroscopic properties, including large scale
systems, evolve from smaller component systems and networks. Focus on the
word emergence.
Sheet No. 2
1. Analyze each of the expressions for photolithography resolution and explain how
to maximize resolution in every case. What are the advantages and disadvantages
of using e-beam lithography compared to typical photolithography using UV
radiation? What is the most likely next generation lithography?
2. An exposure is performed with coherent light using a step-and-repeat projection
printing system. The light source has a wavelength of 365 nm (I-line of a Hg arc
lamp). The pattern is a grating with a line-to-line spacing of 1 mm.
(i) Calculate the minimum value of the numerical aperture (NA) which will
provide contrast at the image plane (the plane of the resist).
(ii) What is the maximum value of the numerical aperture, above which there will
be no improvement in image quality?
(iii) Calculate the depth of field of the image for cases (i) and (ii).
3. Which statements are NOT correct?
(i)The primary components of a positive photoresist are
a. Non-photosensitive base phenolic resin
b. Photosensitive dissolution inhibitor
c. Coating solvent
(ii) Projection lithography resolution is limited by exposure wavelength, resist
thickness, and diffraction and dispersion of light.
(iii) Proximity lithography resolution is limited only by exposure wavelength and
resist thickness.
4. Why can only proximity masking be used in the case of X-ray lithography? What
about projection printing with X-rays? Sketch the process for fabricating an X-ray
mask. What are some of the positive attributes of X-ray lithography? What are the
negative attributes?
5. Compare UV, X-ray, ion-beam, and electron-beam lithography. Summarize in a
comparison table. Which techniques are used mostly in the IC industry today?
How are the photons or charged particles created in each case?
6. Stearic acid molecules at the water-air interface are transferred to a hydrophilic
solid substrate forming a Langmuir-Blodgett film. The sequence of passages is as
follows: downward, upward and downward stroke.
i). Use diagrams to indicate the configuration of stearic acid molecules after each
passage.
ii). What is the total number of molecular layer at each side of the substrate after
the third passage?
7. You are asked to modify a sensor surface that is made of glass using selfassembled method. The sensor is used for long-term implantation into human
body. Modifying molecule to be chosen from is either alkanethiol or
alkylchlorosilane molecules.
i). State one advantage and one possible disadvantage of using
alkyltrichlorosilane molecules.
ii). What do you need to do in order to put alkanethiols on a glass surface.
iii). State one disadvantage of using alkanethiols.
iv). You want to make the resulting surface extremely hydrophobic, with
advancing water contact angle (q) close to 110°. Suggest a functional group of the
alkyltrichlorosilane molecules that fit into this criterion.
v). To your surprise, q is a lot lower than the expected value. Suggest a reason for
that.
vi). Name two characterization techniques that can help you to find out the
chemical functionalities of the deposited layer of molecules.
8. You are encapsulating hemoglobin using layer-by-layer (LbL) method. The pH
used is 8.0. What kind of polyion will you use, positively charged or negatively
charged? State briefly your reasoning. Name one polyion you would use.
Sheet No. 3
1. List the different methods for the creation of Zero-Dimensional and ThreeDimensional structures and write the salient principles behind the same – This
should be from the notes (power-points) I gave you.
2. List the different methods for the creation of Zero-Dimensional and ThreeDimensional structures and write the salient principles behind the same – This
should not be from the notes (power-points) I gave you – so obviously, you have
to look for the latest review papers in different scientific journals (try getting
papers within the last 5 years).
Sheet No. 4
1. List the different methods for the creation of One-Dimensional structures and
write the salient principles behind the same – This should be from the notes
(power-points) I gave you.
2. List the different methods for the creation of One-Dimensional structures and
write the salient principles behind the same – This should not be from the notes
(power-points) I gave you – so obviously, you have to look for the latest review
papers in different scientific journals (try getting papers within the last 5 years).
Sheet No. 5
1. List the different methods for the creation of Two-Dimensional structures and
write the salient principles behind the same – This should be from the notes
(power-points) I gave you.
2. List the different methods for the creation of Two-Dimensional structures and
write the salient principles behind the same – This should not be from the notes
(power-points) I gave you – so obviously, you have to look for the latest review
papers in different scientific journals (try getting papers within the last 5 years).
Sheet No. 6 (Optional – Bonus marks will be provided for this section)
Use any resource available on the internet and produce working models of anything
related to nanotechnology/nanobiotechnology. Of course, it goes without saying that
these models should be pertaining to your CAM 1 portion. You can also create
models from the syllabus being covered after CAM 1. Each student has to produce
one model and demonstrate in the class to their friends. A partial list of internet
resources is listed below http://www.nano.gov/education-training/center/teacher-resources
http://nanosense.org/activities.html
http://mrsec.wisc.edu/Edetc/modules/index.html
http://mrsec.wisc.edu/Edetc/IPSE/educators/index.html