Dr Brendan J. Howlin joined the University of Surrey in September 1987 to teach on the new computer aided chemistry degree course. He currently teaches IT skills, advanced mathematics, molecular modelling and DNA profiling.
He graduated with BSc and PhD from the University of Essex, having studied the inorganic chemistry of microbial iron transport compounds, using Mossbauer spectroscopy and X-ray crystallography. He also carried out postdoctoral pharmaceutical and protein modelling studies at Birkbeck College in the University of London and Pfizer Ltd.
Areas of specialism
University roles and responsibilities
- Chemistry Athena Swan Lead
- Member of IT Governance Committee
- Member of FEPS Equality and Diversity Committee
Alternative to traditional batteries moves a step closer to reality after exciting progress in supercapacitor technology
New breed of supermolecule ‘hunts down’ harmful drugs and removes them from water
In the media
My research interests currently centre on molecular modelling and developing supercapacitors. Molecular modelling covers molecular mechanics, molecular dynamics, QSPR and molecular orbital calculations on synthetic polymers, proteins and drug design. The supercapacitor research involves developing the next generation of high energy density supercapacitor materials
- Major scientific breakthrough research has discovered new materials offering an alternative to battery power proven to be between 1,000-10,000 times more powerful than the existing battery alternative - a supercapacitor.
- The new technology is believed to have the potential for electric cars to travel to similar distances as petrol cars without the need to stop for lengthy re-charging breaks of between 6-8 hours, and instead re-charge fully in the time it takes to fill a regular car with petrol.
- The scientific findings made by Augmented Optics Ltd and its wholly owned subsidiary Supercapacitor Materials Ltd with the University of Surrey and University of Bristol have produced a safer, faster charging, more efficient and greener alternative to battery power and supercapacitor abilities as we currently know them.
We collaborate with supercapacitormaterials on supercapacitors (http://www.supercapacitormaterials.com/)
Dr Ian Hamerton (University of Bristol) on polymeric materials (http://www.bristol.ac.uk/engineering/people/ian-hamerton/index.html)
Dr Daniel Meijles (St. George's, University of London) on anti-ageing drugs (https://www.sgul.ac.uk/research-profiles-a-z/daniel-n-meijles)
Postgraduate research supervision
Currently supervising a PhD student (Maryam Sairi, sponsored by the Malaysian Government) on predicting the char yield of Benzoxazines by QSPR. These materials are widely used as fire retardant coatings, so maximising the char yield is paramount.
Completed postgraduate research projects I have supervised
Lisa Mc Namara
Meqna Wan Hassan
Courses I teach on
of the polymers studied. The latter is interesting since it is superior to many commercial benzoxazines with a relatively high T
(235 °C), flexural modulus (5.0 GPa) and flexural strength (146.7 MPa), but coupled with a breaking strain (3.06%) that is uncharacteristically high for polybenzoxazines. The incorporation of fluorine results in a low dielectric loss properties (D
= 3.71-4.12 at 10 MHz, D
= 0.0109 - 0.0980 at 10 MHz), which are comparable with commercial polybenzoxazines, FR4 and aerospace epoxy resins and superior to commercial bismaleimides.
9) and compared to published thermal data; in all of the QSPR models there is a high level of agreement between the actual data and the predicted data (within 0.63-1.86 K of the entire dataset). The water accessible surface area is found to be the most important descriptor in the prediction of T(g). Molecular modelling simulations of the benzoxazine polymer (minus initiator) carried out at the same time using the Materials Studio software suite provide an independent prediction of T(g). Predicted T(g) values from molecular modelling fall in the middle of the range of the experimentally determined T(g) values, indicating that the structure of the network is influenced by the nature of the initiator used. Hence both techniques can provide predictions of glass transition temperatures and provide complementary data for polymer design.
oxidase, Computational Biology and Chemistry 39 pp. 6-13 Elsevier
which by generating reactive oxygen species (ROS) plays important role in regulating cellular function.
p22phox stabilises the Nox enzyme, assists in catalytic core maturation and in the meantime provides an
anchoring site for cytosolic regulatory subunits to bind. However, the protein structure of the p22phox is
still uncertain. In this study we use an in silico computational bioinformatic approach to produce a consensus
3-dimensional model of the p22phox. Based on published protein sequence data of human p22phox
and by using transmembrane specific protein prediction algorithms, we found that p22phox consists of
two domains: an N-terminal transmembrane domain (124 a.a.) and a C-terminal cytoplasmic domain (71
a.a.). In its predicted most stable form, p22phox contains three transmembrane helices leading to an extracellular
N-terminus and an extensive (39 a.a.) extracellular loop between helices 2 and 3. Furthermore,
we locate the cytosolic domain phosphorylation site at threonine147 which literature shows is capable of
priming the p22phox, in order to accept its binding partners. Our results are consistent with the biological
characterisation of p22phox derived from experiments using specific antibody or genetic manipulation.
Our 3-D protein model provides insights into the biological function of p22phox and cytochrome b558, and
can be used as tool to investigate the regulatory mechanism of Nox isoforms.
Polyarylethersulphones Using QSPR Methods, PLoS One 7 (6) e38424
polyarylethersulphones. A general equation is reported that calculates the glass transition temperatures with acceptable
accuracy (correlation coefficients of between 90?67%, indicating an error of 10?30% with regard to experimentally
determined values) for a series of 42 reported polyarylethersulphones. This method is quite simple in assumption and relies
on a relatively small number of parameters associated with the structural unit of the polymer: the number of rotatable
bonds, the dipole moment, the heat of formation, the HOMO eigenvalue, the molar mass and molar volume. For smaller
subsets of the main group (based on families of derivatives containing different substituents) the model can be simplified
further to an equation that uses the volume of the substituents as the principal variable.
Structure-Property Relationship (QSPR) approach, and was proven to be useful to make good prediction models
for series of polybenzoxazines [1?3]. However, the effect of heterogeneities in the crosslinked network to the
prediction accuracy is yet to be tested. It was found that polybenzoxazines with polymerisable functional group
(e.g. acetylene-based benzoxazines) form up to 40% higher char yield compared to their analogue polybenzoxazines
due to the contribution of the polymerisable functional group (e.g. ethynyl triple bond) in the
cross-linked network. In order to investigate the effect of the inconsistent cross-linking network, a data set
consisting of thirty-three benzoxazines containing various structures of benzoxazines was subdivided into two
smaller data sets based on their functional group, either benzoxazines with polymerisable functional group
(acetylene-based benzoxazines set (Ace-M)) or non-polymerisable functional group (aniline-based benzoxazines
(Ani-M)). Char yield predictions for the polybenzoxazines for these data sets (Ace-M and Ani-M) were compared
with the larger thirty-three polybenzoxazines data set (GM) to investigate the effect of the inconsistency in
crosslink network on the quality of prediction afforded by the model. Prediction performed by Ace-M and Ani-M
were found to be more accurate when compared with the GM with total prediction error of 3.15% from both
models compared to the GM (4.81%). Ace-M and Ani-M are each better at predicting the char yields of similar
polybenzoxazines (i.e. one model is specific for a polymerisable functional group; the other for non-polymerisable
functional group), but GM is more practical as it has greater ?general? utility and is applicable to
numerous structures. The error shown by GM is considerably small and therefore it is still a good option for
prediction and should not be underestimated.
epoxy resins, Polymer 139 pp. 163-176 Elsevier
difunctional diglycidyl ether of bisphenol A (DGEBA) is explored using thermal and spectroscopic
methods. Investigation of the 1,3-dialkylimidazolium based ionic liquids comprising the common
cation (1-ethyl-3-methylimidazolium) and different anions (acetate, diethyl phosphate, dicyanamide
or thiocyanate) via thermogravimetric analysis revealed 1-ethyl-3-methylimidazolium acetate to be
the least thermally stable, both in air and nitrogen, and 1-ethyl-3-methylimidazolium dicyanamide
to be the most thermally stable. Dynamic differential scanning calorimetry reveals the formulations
comprising DGEBA and ionic liquid where it was revealed that the lowest and highest temperature
for the onset of reaction were observed for formulations with 1-ethyl-3-methylimidazolium acetate
and 1-ethyl-3-methylimidazolium dicyanamide respectively. 1-Ethyl-3-methylimidazolium acetate
was shown, via nuclear magnetic resonance (NMR) spectroscopy and residual gas analysis, to
degrade at 150 °C to yield dealkylated products including methyl acetate and ethyl acetate as well
as 1-methylimidazole and 1- ethylimidazole. The dealkylated imidazole ring is proposed as a route
for initiation of the epoxy ring. Adduct formation between 1-ethyl-3-methylimidazoloium acetate
and benzaldehyde at room temperature was observed leading to the proposal of the generation of a
carbene species as a route for initiation of the epoxy ring in formulations with the acetate anion.
NMR analysis of formulations comprising 1-ethyl-3-methylimidazolium thiocyanate and epoxy are
believed, at room temperature, to initiate via reaction of the thiocyanate anion with the epoxy ring.At elevated temperatures, it is proposed that a second, competing reaction, involving deprotonation
of the imidazolium ring, also becomes active. The three proposed reaction pathways, namely the
carbene route, the imidazole route and the counter-ion route, are all proposed to occur when an
ionic liquid is used to initiate an epoxy resin.
pathway from fundamental studies to the
selective removal of fluorides and
phosphates from water, Journal of Hazardous Materials Elsevier
exhibit outstanding mechanical properties when analysed under applied loads of 0.1?300 mN. Following
charring (900 C for 10 minutes to achieve graphitised structures), the samples display a remarkable
combination of a modulus of elasticity of around 25 GPa and nanohardness of 300 kgf mm2, making
them some 30?40% stiffer than bone and practically as hard as tooth enamel. At the same time we find
that under the same conditions the chars are highly resilient, displaying complete elastic recovery with
very little plastic deformation. When cured in the presence of copper(II) acetylacetonate (200 ppm) in
dodecylphenol (1% w/v active copper suspension) to form a polycyanurate, compound (2) forms a dense,
consolidated structure compared with compound (1) under the same conditions. At high magnification,
the presence of a nanoscale, fibrillar structure is observed, accounting for the high resilience.
In order to do that, the QSPR models were tested over a series of internal and external validation tests to explore their internal and external predictivity, prior to experimental validations which were performed later and reported in Chapter 7. The internal and external validations found out that the discrepancy in the general model (GM) which was initially thought to be a drawback to the model?s performance was actually not, as it does not compromise the model?s prediction accuracy, both internally and externally. The validation process also found that one of the structure-specific models, Ph-M (aniline-based benzoxazines) is externally predictive whilst another structure-specific model, the Ace-M (acetylenic-based polybenzoxazines) is not internally and externally predictive due to the too small training set that affects its predictivity performance.
An acetylenic-based polybenzoxazine, poly(BA-apa) and a benzylamine-based polybenzoxazine, poly(BO-ba) have been successfully synthesised in this work. Both materials have been characterised using Fourier Transform ? Infra Red Spectroscopy (FT-IR), Nuclear Magnetic Resonance (NMR) spectroscopy (both 1H and 13C) and Liquid Chromatography-Mass Spectrometry (LC-MS) to confirm their structures. These materials were analysed using Differential Scanning Calorimetry (DSC) to study their polymerisation behaviour and were later cured and taken further to Thermogravimetric Analysis (TGA) in order to investigate their thermal properties and the amount of char yield formed upon heating at 800 oC under an inert (nitrogen) atmosphere ? which then will be used for experimental validation of the QSPR models.
The study of DSC thermograms showed that both polymers exhibit a distinct polymerisation behaviour e.g. BA-apa went through two polymerisation reactions simultaneously (the oxazine ring opening polymerisation and the acetylene addition reaction) whilst BO-ba only polymerised via the ring opening reaction from the oxazine rings. It was also found that BA-apa has a lower polymerisation activation energy, consistent to its lower polymerisation temperature in comparison to the BO-ba.
TGA analysis revealed that poly(BO-ba) formed an average of 44.35 % char yield and poly(BA-apa) on the other hand formed approximately 10 % higher char which is 56.28 %. The analysis also discovered that poly(BA-apa) synthesised in this work formed 15 % less char yield than previously reported in the literature (56.28 % vs. 71 %1) due to the shorter curing schedule. The final QSPR validation which is the experimental validation found that the char yield of poly(BO-ba) was predicted very well within 5-7 % error by both GM model and Ph-M. Ace-M which was reported earlier as not internally and externally predictive, has made a nearly accurate prediction towards the char yield of poly(BA-apa), close to the literature value of 71 %. The GM model has also made a close prediction to the Ace-M model, but these predictions deviated 15-17 % from the experimental poly(BA-apa) char yield measured in this work.
dehyde in various stoichiometries (from equimolar reaction to benzaldehyde in 10-fold excess) and the resulting
adducts were characterized using nuclear magnetic resonance spectroscopy (¹H, ¹³C, DEPT, and HQSC experi-
ments). Differential scanning calorimetry was used to examine the initiating behaviour of the adducts towards
mono- and di-functional epoxy resins and the data were used to determine kinetic parameters for the poly-
merization. The lower temperature peak, due to carbene formation, is sensitive to adduct concentration; the
residual ionic liquid in the adduct mixture contributes towards the initiation of the curing reaction. When a
monofunctional epoxy and the 1:1 adduct was subjected to a 2-week period of storage at room temperature and
sub-zero temperatures in the freezer, the profiles of the thermograms for the frozen samples do not change
considerably over the storage period and the formulation retains a light yellow colour (rather than the viscous,
dark red appearance of the formulation stored at room temperature).
Liquid filters are high area and diffusive flow through fully water-wetted pores masks bulk flow from the smallest defects during FF, so an alternative fluid was sought. Solutions were modelled and properties influential to diffusive flow identified using multi-linear regression. These were used for alternative fluid selection. Maltitol was identified as the fluid that would theoretically demonstrate most improvement. Experimental confirmation revealed a flow reduction of 23% at 10% concentration, compared with water.
WIT measures ?flow? through an un-wetted filter under pressure. If there is a defect present, this pressure will be sufficient to achieve breakthrough and the test will report a failure. Questions about WIT remained unanswered: what is the mechanism of ?flow?, and why is pressure the driver? The latter remains unanswered but conclusively demonstrated, and the former was proven as evaporative flow of water vapour. Salt/water was used, and conductivity reduced from 17.23 µS upstream to ~0 µS downstream, proving that the flow is water vapour evaporation.
Both tests have been improved by filter design.
FF requires every pore be fully wetted. An incompatibility between polypropylene and polyethersulphone means sometimes this cannot occur. The surface energy of the polypropylene is the property that provides the problem so it was altered by the incorporation of POSS, bringing the contact angle from 99.7° to 85.8°.
Altering air filter design to accommodate increased flow during WIT would be advantageous as customers relate higher flows to higher reliability. Space downstream was introduced by using a thicker support layer to increase flow successfully. Further improvement was demonstrated by modifying the core to a ?star? design, increasing flow by 3.3x for a commercially-available product and by 2.8x for an R&D prototype.
and characterised by Mass and FT- IR Spectrometry, Scanning Electron Microscopy (SEM) and
Energy Dispersive X-ray (EDX). Information regarding the ability of the dimer to interact with metal
cations was obtained from FTIR and SEM-EDX analyses. A striking feature of micrographs of the
loaded dimer is the change of morphology with the cation. Based on these results, optimal conditions
for removing cations from water were assessed under different experimental conditions. Results
obtained demonstrate that the removal process is fast. Capacity values and selectivity factors show that
the dimer is selective for Hg(II) in one and in multiple component metal solutions relative to other
cations. Single-ion transfer Gibbs energies from water to a solvent containing common functionalities to
those of the dimer were used to assess the counter-ion effect on the removal process. Agreement is
found between these data and energy calculations derived from Molecular Simulation studies. Studies
on polluted water in the presence of normal water components in addition to toxic metal cations are
reported. Further experimental work on wastewater from the mining industry is in progress.